JP5412836B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, a plotter, and a printing apparatus that employs an ink jet recording method, and a multifunction machine including one of these, and more particularly, bleeding (feathering, bleeding, etc.). The present invention relates to an image forming apparatus that applies a liquid (or gel or both) that can be in a foam state having a function as a set agent that suppresses and enables high-density and high-saturation image formation to be applied to a recording medium in the form of fine bubbles.
The present invention can be applied to inkjet technology such as textile printing and surface treatment (liquid application of ink permeability modifier, gloss material, coating material, etc.) apparatus.

As an image forming apparatus such as a printer, a facsimile machine, a copying machine, or a multifunction machine of these, for example, a recording head composed of a liquid ejection head that ejects liquid droplets of a recording liquid is used, and a recording medium (hereinafter also referred to as “paper”). However, the material is not limited, and a medium, a recording medium, a transfer material, a recording paper, etc. are also used synonymously, and droplets are attached to the paper to form an image (recording, printing, printing). , Printing is also used synonymously).
The “image forming apparatus” means an apparatus that forms an image by landing droplets on a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics or the like.
Further, “image formation” not only means that an image having a meaning such as a character or a figure is imparted to the medium, but also that an image having no meaning such as a pattern is imparted to the medium.
Further, the “recording liquid” is not limited to ink, and may be any liquid that can form an image in the above sense and can be formed into droplets upon ejection.

In such a liquid discharge type image forming apparatus, since a recording liquid containing color material (hereinafter referred to as “ink”) is formed into droplets to form an image, the dots formed by the droplets are disturbed in a whisker shape. Feathering, color bleed that causes colors to blur when the ink droplets of different colors are struck on the paper adjacent to each other, lack of color (density), show-through, glossiness, fixability Such a problem may occur.
Further, in addition to the initial quality problem that it takes time for the droplets on the paper after printing to dry, there are problems relating to fastness such as water resistance, light resistance, scratch resistance, and ozone resistance.

Conventionally, as described in Patent Document 1, a pretreatment liquid that reacts with ink to prevent bleeding is applied with an application roller, or as described in Patent Document 2, the pretreatment liquid is liquid. For example, the liquid is ejected in a mist form from the ejection head.
Patent Document 3 describes that the treatment liquid for improving the fixing property of the ink is applied before or after ink printing, and is not limited to the pretreatment, and there is a case where a posttreatment is performed.
However, as described in Patent Documents 1 to 3, in the method in which the pretreatment liquid or the posttreatment liquid is spouted by the application roller or the liquid discharge head, application unevenness occurs (first problem) and the liquid For this reason, there is a problem in the quick drying property after reacting with the ink on the paper. In particular, the paper is likely to be wrinkled or curled or bent, so that jamming is likely to occur (second problem).

JP 2002-137378 A Japanese Patent Laying-Open No. 2005-138502 JP 2003-205673 A JP 2008-94055 A Japanese Patent Laid-Open No. 08-72227

In order to solve the above-mentioned problems, the present applicant has proposed a technique for applying a treatment liquid in a foam state in Japanese Patent Application No. 2007-178698.
The “bubble state” refers to a state in which a large amount of bubbles are dispersed in the liquid and the liquid is compressible. For example, the following advantages can be obtained in the foam state as compared with the liquid or mist processing liquid.
(1) Since the foam contains a large amount of air, a small amount of liquid can be applied.
(2) Since the foam is close to a solid, the coating film thickness can be easily adjusted by scraping after application, etc., and the releasability from the application means during application from the application means to paper is good, Uniform application is possible.
(3) Since water does not easily penetrate into the fibers of the paper, wrinkles and curls are unlikely to occur on the paper.

The above advantages do not depend on the type of treatment liquid, and the same effect can be obtained. The treatment liquid desirably has an effect of suppressing paper dust, and may have an effect of changing the background color of the paper.
However, in the foam coating apparatus that applies the treatment liquid to the recording medium with foam, if the increase or decrease of the foam supply amount according to the width of the recording medium or the control of the application width is not performed, the supply of foam is insufficient or excessive. It arises (third problem).
If the coating area is equal to or larger than the recording material width, surplus bubbles will ooze out from the opposite ends of the recording medium to the surface opposite to the coating surface (fourth problem).
The treatment liquid adhering to the unnecessary application area spreads to another part in the application apparatus (fifth problem).
The generation of these unnecessary bubbles wastes the processing liquid (sixth problem).
By not controlling the bubble supply amount according to the recording medium width, if the bubble supply amount becomes excessive, it leaks into and out of the coating device, contaminates the inside of the device, or unnecessarily adheres to the recording material. (Seventh problem).
Moreover, when the amount of foam supply becomes insufficient, uneven foam application occurs (eighth problem).

The inventions described in Patent Documents 1 to 5 all have the following problems in common.
In the structures of these inventions, since the processing liquid is always applied to both sides of the recording medium, for example, even when printing on only one side, the printing surface that does not need to be originally applied with the processing liquid The processing liquid is applied to the surface opposite to the surface, and the recording medium of any width adheres to the roller that is in contact with the opposite side of the application surface (before the paper is nipped). While the treatment agent remains on the roller surface, it is also applied to the back surface, but it is gradually transferred to the back surface of the paper, and when the treatment agent decreases, the concentration at which the treatment agent is applied to the back surface of the paper gradually increases. It will decline. This means uneven application of the treatment agent on the back side of the paper.
In such a case, the image defect due to the non-uniformity of the processing agent on the back side during double-sided printing and the characteristics of the paper (curling occurrence status, effect of the processing agent on the image, etc.) become non-uniform. There arises a problem that the quality is significantly impaired (ninth problem).

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can solve the above-described problems.

In order to achieve the above object, according to the first aspect of the present invention, in an image forming apparatus for forming an image on a recording medium, the liquid and gel are applied to the recording medium or an intermediate member applied to the recording medium. A foam applying means for applying a foam having at least one of them in the form of a foam as a processing agent or a fixing agent, the foam applying means comprising: a foam generating means for generating the foam; and a foam generating means from the foam generating means to the applying means. A bubble extending in the recording medium width direction perpendicular to the recording medium conveyance direction when the recording medium is supplied, and the bubble supplied from the bubble generating means passes through the extension part to be recorded on the recording medium or the An application unit that applies to the intermediate member, a foam storage unit that is formed in an application area of the application unit and stores the foam supplied from the foam generation unit, and a foam that detects the amount of foam stored in the foam storage unit A quantity detecting means, Based on the information of the foam volume by Kiawah amount detecting means, and controlling the foam volume to be supplied from said foam generating means.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, a supply width variable capable of changing a supply width in the recording medium width direction of the bubbles supplied from the bubble generating means to the coating means. And the foam amount supplied from the foam generating means is such that the amount of foam stored in the foam storage section is within a predetermined range between the minimum width and the maximum width of the supply width variable means. Control is performed to determine the command value of the quantity .
According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the coating width can be changed in the width direction of the recording medium for the bubbles supplied from the bubble generating unit to the coating unit. And the foam amount supplied from the foam generating means so that the amount of foam stored in the foam storage section is within a predetermined amount range from the minimum width to the maximum width of the application width variable means. Control is performed to determine the command value of the quantity .

According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect , the bubble amount detection unit includes a bubble height detection unit that detects a bubble height of the bubble storage unit in a non-contact manner, and the bubble. A foam amount calculating means for calculating the amount of foam to be supplied from the foam generating means from the relationship between the bubble height detected by the height detecting means and the width information of the supply width variable means or the application width variable means; It is characterized by having .
According to a fifth aspect of the present invention, in the image forming apparatus according to the second or third aspect , the foam height detecting plate is displaced according to the foam height of the foam storage section, and the foam height detecting means is The position of the bubble height detection plate is detected as the bubble height .

According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the second to fifth aspects, the supply width varying unit or the coating width varying unit moves the bubble reservoirs from each other in the recording medium width direction. It has a pair of partition members that can move in the opposite direction, and after fixing the pair of partition members to a desired width, it is confirmed from the foam amount detection means that a predetermined amount of bubbles has accumulated in the foam reservoir. And performing feedback control for determining a command value for the amount of foam supplied from the foam generating means .
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the second to fifth aspects, the supply width varying unit or the coating width varying unit moves the bubble reservoirs from each other in the recording medium width direction. Having a pair of partition members that can move in the opposite directions, after fixing the pair of partition members at a position narrower than a desired width, the supply of foam is started, and the pair of partition members with a predetermined width while gradually expanding And detecting that a predetermined amount of bubbles has accumulated in the bubble storage unit based on information from the bubble amount detecting means, and determining a command value for the amount of bubbles supplied from the bubble generating means It is characterized by performing feedback control .

According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the second to fifth aspects, the supply width varying unit or the coating width varying unit is configured such that the bubble storage unit is opposite to the recording medium width direction. After having a pair of partition members that can move in the direction and fixing the pair of partition members at a position narrower than a desired width, foam supply is started, and at the same time, information on the amount of bubbles from the bubble amount detection means is acquired. However, when the pair of partition members are expanded stepwise, the pair of partition members are returned to a slightly narrowing direction, and finally the position of the pair of partition members is fixed to a desired width, and a predetermined amount is stored in the foam storage unit. It is characterized in that the accumulation of bubbles is detected based on information from the bubble amount detection means, and feedback control is performed to determine a command value for the amount of bubbles supplied from the bubble generation means .
According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the second to fifth aspects, the supply width varying unit or the coating width varying unit is configured such that the bubble storage portion is opposite to the recording medium width direction. Having a pair of partition members movable in the direction, having a print command, and acquiring the amount of foam stored in the pair of partition members from the foam amount detection means in a step immediately before image formation; The pair of partition members are moved to a width in accordance with a print command, and after calculating and calculating the excess and deficiency of bubbles with respect to a desired amount of the width, the pair of partition members are moved, and the excess and deficiency of bubbles Feedback control is performed to determine a command value for the amount of foam supplied from the foam generating means based on the calculated value .

According to the present invention, it is possible to stably supply foam with a margin without being interrupted. In addition, by detecting and controlling the amount of stored foam, it is possible to prevent overflowing, and to prevent the vicinity of the apparatus from being spilled and the penetration of the back side of the paper.
If the foam fluidity is relatively high, the top of the foam in the foam reservoir naturally becomes flat (approaching) due to the action of gravity, so the foam height can be measured with a simple structure, and the foam is not contacted. The internal pressure of the foam does not increase, foam crushing hardly occurs, and leakage due to the internal pressure of the foam reservoir can be prevented.
Even if the fluidity of the foam is relatively low and the upper part of the foam is difficult to flatten only by the action of gravity in the natural state, the foam height detection plate detects the foam height while keeping it flat evenly from above. Therefore, accurate detection can be performed.
In addition, even if the bubble distribution is in a non-uniform state by using the bubble height detection plate, the effect of uniform distribution by applying pressure uniformly in the width direction by the action of pressing force from above Can also be obtained.
According to the present invention, it is possible to control the amount to be supplied without being deficient while monitoring the amount of foam consumed every time even during the printing processing operation.
In addition, even if the bubble height increases or decreases depending on the printing command due to a sudden change in the partition width, the bubble supply command value is determined by calculating the amount of bubbles corresponding to the application area according to the printing command. Supply and foam overflow can be prevented.

When supplying low-fluid foam to the foam reservoir, even if the supply is started with the desired partition wall width from the beginning, it may be assumed that the foam does not flow evenly. In order to prevent this, the bottom of the reservoir is caused by the action of gravity. The internal pressure increases and the force to spread in the lateral direction increases, and the action of spreading bubbles quickly and evenly works.
By using such force and expanding the partition width in a state where it is increased to the extent that the foam does not overflow, there is an effect that the distribution of the entire foam storage part becomes uniform, and it is possible to stably supply the foam and Overflow can be prevented.
Furthermore, when the bubble spreads once the bubble has adhered to the partition wall by returning the partition wall slightly, the bubble expands while being pulled, and then returns to the narrowing direction to increase the amount of foam attached to the partition wall. By increasing the amount of foam to be produced, the effect of quickly storing the foam in the entire foam storage section is obtained.
When receiving a large amount of continuous printing commands, first, in order to recognize the amount of foam remaining in the current foam storage unit, the amount of foam is detected by the foam amount detection means, and then the amount of foam is determined to be insufficient. If it is, the amount of foam added according to the shortage is predicted and calculated, and then the partition width is set to a width according to the print command, and then the amount of foam consumed from the foam amount detection means. By replenishing with feedback control, it becomes possible to supply a stable foam.
If the amount of foam supplied into the foam reservoir in the state of the maximum partition width exceeds the maximum foam storage limit, when the width is reduced from the maximum partition width state to the minimum partition width state, the storage limit is exceeded. Therefore, the foam may overflow, while the foam volume supplied to the foam reservoir in the state of the maximum partition width is controlled so as not to exceed the maximum foam storage limit, Even when it is in a state, the bubbles can be stored without overflowing, so that the bubbles can be supplied stably.
Furthermore, since it can be stored without causing a sudden overflow of bubbles when changing the partition wall width, a stable supply of bubbles is possible.
Even when expanded to the state of the maximum partition wall width, the foam storage distribution can be satisfied without being exhausted in some places, so that stable foam supply is possible.
Furthermore, when the partition wall width is changed, the sudden bubble distribution can be stored without being interrupted and depleted, so that it is possible to supply a stable bubble.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the structure of the application means of a foam application apparatus, (a) is a left view, (b) is an upper side view. It is a figure which shows the principal part of a bubble production | generation means. It is a perspective view which shows a pair of partition member. It is an upper side view of an application means when a partition member is set to the maximum width. It is a left view which shows the supply state of the bubble in the state in which the partition member was set to the maximum width. It is an upper side view of an application means when a partition member is set to the minimum width. It is a left view which shows the supply state of the bubble in the state in which the partition member was set to the minimum width. It is a figure which shows the detection state of the foam height using the bubble spill prevention function by the flap in a foam storage part, and the board for foam height detection. It is a figure which shows the state which detects directly the foam height in a foam storage part, without using the board for foam height detection. It is a figure explaining the bubble spill phenomenon when there is no sealing means (flap) in a bubble storage part. It is a flowchart of processing agent application control. Max. It is a flowchart of the subroutine of a width x length correspondence process. It is a flowchart of a subroutine of size A width × length correspondence processing. It is a flowchart of a subroutine of size N width × length correspondence processing. Min. It is a flowchart of the subroutine of a width x length correspondence process. It is a figure which shows a bubble amount control setting state, (a) is a left view when a partition is set to the maximum width, (b) is a left view when a partition is set to the minimum width. It is a graph which shows the setting value of the sensor detection distance in the bubble supply restriction control corresponding to the partition wall width. It is a characteristic view of the table data which calculates | requires the additional amount (height) of the bubble to a bubble storage limit value based on partition wall width information and sensor detection distance information. In other embodiment, it is a figure which shows the condition of the partition width control from the foam supply initial stage to completion, (a) is a left view of an application | coating means, (b) is a timing chart. In other embodiment, it is a figure which shows the condition of the partition width control from the foam supply initial stage to completion, (a) is a left view of an application | coating means, (b) is a timing chart. It is a system control block diagram. It is a figure which shows the storage state of a bubble when a partition wall width is narrowed from the maximum to the minimum. It is a graph which shows the relationship between the maximum safe bubble storage amount and the safe foam storage amount in a partition wall width variable range. It is a figure which shows the storage state of the bubble when expanding the partition wall width from the minimum to the maximum. It is a graph which shows the relationship between the minimum safe foam storage amount and the safe foam storage amount in a partition wall width variable range.

Embodiments of the present invention will be described below with reference to the drawings.
First, an example of an image forming apparatus including a foam application device as a foam application unit according to the present embodiment 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 droplets onto a paper 100 that is a recording medium, a belt conveyance device 102 that conveys the paper 100, and the paper 100. A foam is applied to the paper 100 that is a member to be applied on the upstream side in the paper transport direction from the recording head unit 101, and a paper discharge tray 104 that discharges the paper 100 on which an image is formed. And a foam application device 200 as a foam application means.

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 (C) and recording heads 101y, 101m, 101c, and 101k that discharge ink droplets as recording liquids of black (K) are provided. Note that the recording head can be mounted on the carriage as a serial type image forming apparatus.
The belt conveyance device 102 is configured such that a conveyance belt 102 a that is an endless belt is looped around a conveyance roller 121 and a tension roller 122. For holding the paper 100 on the conveyance belt 102a, for example, electrostatic adsorption, adsorption by air suction, or other known conveyance means can be used.
The paper 100 stored in the paper feed tray 103 is separated one by one by a pickup roller 131, fed by a pair of transport rollers 132, transported through a transport path 135 by a pair of transport rollers 133 and a pair of registration rollers 134, and foamed. After the foam application is performed by the application device 200, it is fed onto the belt conveyance device 102 and held.
Each color droplet is ejected from the head unit 101 while being conveyed by the belt conveying device 102, and an image is formed on the paper 100 on which bubbles are applied. Thereafter, the paper 100 is discharged to the paper discharge tray 104.

The foam application apparatus 200 includes a container 202 containing a liquid or gel or liquid and gel (hereinafter collectively referred to as “treatment liquid” or “setting agent”) 201 that can be made into a foam state, and the container 202. A pump 203 that pumps the processing liquid 201 from the first, a first foam generating unit 205 that forms a bubble 210a from the processing liquid 201 supplied by the pump 203 via the supply path 204, and forms a part of the foam generating means; The foam supply path 206 that is a path for sending the foam 210a from the one foam generation unit 205 and the foam 210a conveyed through the foam supply path 206 are sheared a plurality of times to form small bubbles (small bubbles) 210 (b, c, d). When the foam is supplied to the second foam generation unit 207 that forms part of the foam generation unit, the foam application unit 208 as an application unit that applies the foam 210 to the paper 100, Recorded And a spreader portion 250 such that the spreader in the width direction perpendicular to the conveying direction of the body.
In the second bubble generation unit 207, net-like bubble refining members 241a, 241b, and 241c that shear the bubbles 210a generated by the first bubble generation unit 205 are arranged, and these are directed toward the bubble application unit 208. The mesh is finely set in stages. The bubbles 210a are sheared every time they pass through these bubble refining members 241a, 241b, 241c, and after passing, become bubbles with a small diameter due to surface tension. This bubble reduction (miniaturization) is performed in stages. In FIG. 3, it has shown by the bubble refinement | miniaturization member 241a, 241b, 241c.
As shown in FIG. 3, the extension part 250 has a manifold part 251 having a predetermined volume and a slit-like outlet 252.
In this figure, the extension diaphragm 260 is omitted for convenience.

Here, the “bubble” is a liquid in which a gas such as air is rounded and formed by the surface tension of the liquid enclosing the gas, and can hold a three-dimensional shape for a certain period of time. . Hereinafter, it is also referred to as “foam”.
The foam having such shape-retaining properties desirably has a bulk density of 0.05 g / cm ³ or less, a foam diameter distribution range of 10 μm to 1 mm, and an average foam diameter of 100 μm or less. In addition, although a bubble is formed in a round shape by itself, when a plurality of bubbles are combined, the shape of each bubble takes a polyhedral shape due to surface tension.
The “bubbles” thus formed are not liquid but semi-solid, and exhibit physical properties close to solid in terms of fluidity.

The refined bubbles are supplied from the right direction in FIG. The foam supplied through the foam supply path 206 that is a pipe path is extended (diffused) in the manifold section 251, passes through the outlet 252, and is supplied to the foam application section 208.
Here, the treatment liquid 201 that can be in a foam state 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 the like (hydroxypropylcellulose etc.) and a solution to which a base such as talc fine powder is added. Furthermore, fine particles can be contained.

As shown in FIG. 1, the first foam generation unit 205 supplies high-pressure air from the high-pressure air supply unit 221 to the processing liquid 201 in the foam generation container 220 via the high-pressure air supply path 223. Bubbles 210 are generated.
When the foam 210 is generated and filled in the foam generation container 220, the foam 210 is supplied toward the foam application unit 208 via the foam supply path 206 by the pressure. The pump 203 closes the supply path 204 so that the bubbles 210 and the process liquid 201 do not flow backward through the supply path 204 for supplying the processing liquid 201 during the generation of bubbles.
The small bubbles 210d supplied from the outlet 252 of the foam spreading section 250 are stored in the foam storage section 237 between the application roller 232 and the foam transport roller 233 constituting the application means (foam application section 208) as illustrated. The

Instead of the application roller 232, a foam generation application roller 234 having a porous elastic surface layer may be substituted. The difference will be described below.
The application roller 232 applies the foam in the foam storage unit 237 to the paper 100 as it is by the pressure of the pressure roller 235, whereas the foam generation application roller 234 has a capillary force regardless of whether it is a closed cell or an open cell. When the surface layer made of an elastic material having a contact with the foam in the foam reservoir 237, even if the foam treatment agent has already been foamed, it is again sucked in by a capillary force such as microcells on the roller surface layer. Although it is pushed out by the pressure roller 235, the processing agent component of a small amount of bubbles confined in the roller bubbles after slightly sucking the bubbles in the original bubble storage portion 237 is divided into new finer bubbles. The so-called foam shear effect has the effect of generating finer bubbles.
Therefore, in the case of this foam generation application roller, since the foam is generated to an area slightly wider than the target foam application area (width), the application range to the paper 100 is slightly expanded, but the foam itself It is expected that the fineness will become fine according to the mechanism described above.

As shown in FIGS. 1 and 2, the bubble storage unit 237 has a pair of partition walls provided at both ends of the transport path (the roller axis direction orthogonal to the sheet transport direction or both ends of the recording medium width direction). There are a front partition 270a and a rear partition 271a as members, and lead screws 272 each having a symmetrical lead at the center in the width direction of the conveyance path penetrate each other, and in the width direction according to the rotation thereof The structure moves in the opposite direction.
As shown in the drawing, the lead screw 272 is driven by a screw feed method including a gear 273 at the end of the lead screw 272, a pinion 274 engaged therewith, and a motor 275 that rotates the pinion 274.
As the type of the motor 275, it is appropriate to use a stepping motor capable of rotating a desired rotation angle with high accuracy. However, the motor 275 is not limited to this as long as accuracy is ensured according to the rotation angle command value. Also good.

As shown in FIG. 2B, when the front partition 270a and the rear partition 271a expand to the vicinity of the maximum width, a home position sensor (hereinafter referred to as “HP sensor”) that contacts the outside of the rear partition 271a. 276) and is used as a sensor for detecting the absolute position for the initialization operation for detecting the initial position of the motor 275.
As shown in FIGS. 1 and 4, the portions of the front partition 270a and the rear partition 271a that are in contact with the bubble transport roller 233 and the pressure roller 235 have an arc shape that follows the outer shape of each roller. Furthermore, Teflon (registered trademark), high-density polyethylene, etc. are affixed to this part to ensure sliding characteristics (reduction of friction coefficient), or an O-ring function is provided to ensure sealing performance. By using the elastic material having the shape, it is possible to reliably retain the foam while preventing wear caused by sliding between the foam transport roller 233 and the pressure roller 235.

As shown in FIG. 4, the front partition 270a and the rear partition 271a are provided with a front insertion portion 270b and a rear insertion portion 271b that extend to the inside of the outlet 252, respectively. A funnel-shaped extending part diaphragm 260 made of an elastically deformable material such as rubber or elastomer is provided between the outer side in the width direction and a supply port 206a as an end of the foam supply path 206. (See FIGS. 1 and 2B).
As a result, the closed partition space is maintained in any width dimension set for the front partition wall 270a and the rear partition wall 271a, and at least a region sandwiched between the front partition wall 270a and the rear partition wall 271a. The small bubbles 210d are prevented from spilling out from the bubble reservoir 237 to the outer region.

As shown in FIG. 4, on the inner side in the width direction of the front partition 270a and the rear partition 271a, a first flap (side flap) 280a is a hinge 280b, and a second flap (side flap) 281a is a hinge 281b. It is provided so as to be able to swing in the vertical direction (height direction of the partition wall member).
A third flap (center flap) 282a extending in a direction perpendicular to the first and second flaps on the upper surface of the outlet 252 at the center in the width direction of the foam reservoir 237 is vertically moved by a hinge 282b. Is provided to be swingable.
These flaps constitute a sealing means for closing a region surrounded by the pair of partition members (the front partition 270a and the rear partition 271a) in the foam storage section 237.
With this configuration, the small bubbles 210d are prevented from spilling from the upper side of the bubble storage part 237 to the outer region.
In FIG. 4, a fixed partition wall 238 and a cleaning blade 236 described later are omitted.

The width dimension of the three flaps has the following characteristics.
As shown in FIG. 2B, the width dimension of the third flap 282a is 100 mm, which is exactly equal to the minimum sheet width conveyed by the image forming apparatus.
The width dimension of the third flap 282a is the same as the inner dimension when the first flap 280a and the second flap 281a are set to the minimum sheet width, and is arranged at the same position.
The first flap 280a and the second flap 281a have a U-shaped cross section that opens downward as shown in FIG. 1 and the like (not shown in FIG. 4). These flaps are slightly dimensioned so that one of them is mounted on the other when the minimum paper width is set, with the attachment positions to the hinges being slightly shifted in the vertical direction.
The lower limit positions of the first flap 280a and the second flap 281a are set so as to hang down slightly.
The third flap 282a presses the first flap 280a and the second flap 281a with its own weight.

The width dimension of the first flap 280a and the width dimension of the second flap 281a are also 100 mm, and these flaps and the third flap 282a are triplely overlapped in the vertical direction. Thereby, even if the inner dimension of the front partition 270a and the rear partition 271a is set to the minimum width size (100 mm), interference between the flaps does not occur.
When the width dimension of the front partition 270a and the rear partition 271a is set to an inner dimension 297 mm corresponding to the maximum sheet width, the first flap 280a and the second flap 281a are also expanded with each other. Since both of them are 100 mm, the third flap 282a is provided with a portion overlapped by 1.5 mm, so that the effect of preventing the leakage of bubbles can be obtained.

FIG. 5 shows an upper side view when the width dimension of the front partition 270a and the rear partition 271a is set to the inner dimension 297 mm corresponding to the maximum sheet width. In this state, the three-stage state of the small bubbles 210d accumulated in the bubble storage unit 237 is individually shown in FIG. 6 as a left side view.
FIG. 6 (a) shows a state where the foam is small, FIG. 6 (b) shows a state immediately after the foam is filled in the foam reservoir 237, and FIG. 6 (c) shows a state immediately before the foam is further supplied and overflowed. Indicates the state.
When the amount of bubbles increases, the first flap and the second flap are pushed up by the pressure and displaced upward.
FIG. 7 shows an upper side view when the width dimension of the front partition 270a and the rear partition 271a is set to an inner dimension of 100 mm corresponding to the minimum sheet width. In this state, the three-stage state of the small bubbles 210d accumulated in the bubble storage unit 237 is individually shown in FIG. 8 as a left side view.
FIG. 8 (a) shows a state where the foam is small, FIG. 8 (b) shows a state immediately after the foam is filled in the foam reservoir 237, and FIG. 8 (c) shows a state immediately before the foam is further supplied and overflowed. Indicates the state.

In these three states, the position of the top surface of the third flap 282a serving as a foam height detecting plate that is displaced using the repulsive force with which the foam contacts is used as the foam height detecting sensor as the foam height detecting means. In 284, detection is made in a non-contact manner.
Based on the relationship between the bubble height detected by the bubble height detection sensor 284 and the width information of the pair of front and rear partition walls, the bubble generation means (CPU as a control means to be described later) will supply from the foam generation means. Calculate the amount of foam.
The bubble height detection sensor 284 and the bubble amount calculation unit constitute a bubble amount detection unit.
The foam amount detection means extracts, for example, the bottom area of the foam storage portion corresponding to the width information of the front partition wall and the rear partition wall from a table stored in the memory in advance, and this value and the bubble height detection sensor 284 The amount of foam (volume) of the foam reservoir is calculated from the detected foam height.

Thus, the force (contact pressure) that pushes away the stored foam around the hinge 282b according to the storage amount of the small foam 210d stored in the foam storage section 237 between the application roller 232 and the foam transport roller 233. FIG. 9 shows the details of a method of swinging the third flap and detecting the amount of displacement by using a non-contact type (optical reflection type) bubble height detection sensor 284.
FIG. 9A shows a state in which the foam in the foam reservoir is not in contact with the flap and is in a small amount of foam, detected by the position of the third flap using the foam height detection sensor 284. Show.
FIG. 9B shows that the foam in the foam reservoir pushes up the first to third flaps and detects that the foam is in a filled state by using the foam height detection sensor 284 based on the position of the third flap. It shows the state.

As shown in FIG. 10, the bubble height detection sensor 284 may directly detect the position of the uppermost bubble in the bubble storage unit.
FIG. 10 (a) shows a state where a small amount of foam in the initial stage of filling of the foam reservoir is detected using the foam height detection sensor 284.
FIG. 10B shows a state in which the filling state of the foam reservoir is detected using the foam height detection sensor 284.

The third flap 282a presses the first flap 280a and the second flap 281a with its own weight from the upper side in any of the above-described three stages, and thereby the first flap and the second flap due to the increase in the bubbles. The foam is prevented from leaking due to the sudden rise of the flap, and the uniform diffusion (extension) of the foam in the roller axial direction is promoted. That is, the function of leveling the foam supplied from the supply port 206a in the roller axial direction (recording medium width direction) is obtained by the pressing action including the first flap and the second flap by the third flap.
The supply port 206a is a connection part between the bubble supply path 206 and the extending part 250, and the width (diameter) thereof is narrower than the minimum width of the movable range of the front partition 270a and the rear partition 271a. Thereby, since the flow of foam spreads every corner, a stable foam distribution function is obtained, and stable foam supply can be performed.

As shown in FIG. 1, a cleaning blade 236 having an arcuate cross section is provided along the downstream end of the front partition and the rear partition in the sheet conveyance direction. The cleaning blade 236 has a length extending over the entire roller axial direction, and is supported by a side plate (not shown) of the foam application unit 208. One end (lower end) of the cleaning blade 236 is in contact with the surface of the application roller 232 in the counter direction, and the residue on the application roller 232 is removed.
As described above, since the cleaning blade 236 has a length extending in the roller axis direction, it is possible to cover a portion of the foam reservoir 237 that cannot be covered with the first flap and the second flap, and prevent foam leakage. It contributes to.
A fixed partition wall 238 having an angled cross section is provided along the upstream end of the front partition wall and the rear partition wall in the sheet conveyance direction. The fixed partition wall 238 has a length extending over the entire roller axial direction, and is supported by a side plate (not shown) of the foam application unit 208. One end (lower end) of the fixed partition wall 238 is in contact with the surface of the foam transport roller 233 to prevent the foam from leaking from the foam reservoir 237.
The fixed partition wall 238 may be supported on the lower surface of the outlet 252 of the extending portion 250 or may be formed integrally with the lower surface of the outlet 252.

As described above, the third flap 282a is provided on the top surface of the foam reservoir 237, and the first flap 280a and the second flap 281a are pressed from the upper side to thereby distribute the foam in the foam reservoir 237. Has the effect of being kept even.
Depending on the amount of small bubbles 210d stored in the application roller 232 or the bubble storage part 237 between the bubble generation application roller 234 and the bubble conveyance roller 233, the third flap is stored around the hinge 282b. Even if the distribution of bubbles is uneven, as shown in FIG. 9, the bubbles are evenly distributed by pressing from above.
If these three flaps are not provided, as shown in FIG. 11, the distribution of the bubbles becomes non-uniform, and in the worst case, the bubbles may leak from the bubble storage portion 237.
In the drawing, the distribution of bubbles in the cross-sectional direction (height direction of the partition wall) is described, but the same phenomenon can occur in the longitudinal direction (the roller axis direction) of the bubble storage portion 237.

When the application roller 232 or the bubble generation application roller 234 and the bubble transport roller 233 are rotated in the rotation direction shown in FIG. 9, the stored bubbles are always placed in a stirring state, so that the bubbles always have a constant cell diameter.
Here, structural differences and functional differences between the application roller 232 and the foam generation application roller 234 will be described.
The structure of the application roller 232 has a smooth surface or a very fine fine-grained surface. Even if the material is an elastic body, the foam material component does not permeate into the material and adheres to the surface. In order to transfer the bubbles to the surface of the paper 100, it has a function of adhering and conveying.
On the other hand, the structure of the foam generation application roller 234 is made of a foamed elastic material having a capillary force regardless of whether the material is a closed cell or an open cell, and when the surface layer comes into contact with the foam in the foam reservoir 237, the foam is already foamed. Even if the foam treatment agent is, it is slightly sucked by the capillary force of the microcell or the like by the polishing surface of the foam on the roller surface layer, and then pushed out by the pressure roller 235 again. A small amount of foam treatment agent confined in the roller bubbles after sucking in the bubbles a little is divided into finer bubbles, so there is an action to generate finer bubbles due to the so-called foam shear effect. In the case of this roller, since bubbles are generated to a region slightly wider than the target bubble application region (width), the application range to the paper 100 may be slightly expanded. The fineness of it is expected that finer as the mechanism described above.

The function of the foam generation application roller 234 corresponds to the application means described in claim 2 . That is, it means that finer bubbles are generated even after the bubbles are supplied to the bubble generation application roller 234, and thus the function of the partition means the width to be supplied to the bubble generation application roller 234. Therefore, the pair of partition walls when the foam generation application roller 234 is used functions as a supply width varying unit.
On the other hand, the function of the application roller 232 corresponds to the application means described in claim 3 . That is, after the foam is supplied to the application roller 232, it means that the application is performed while maintaining the state of the bubble as it is, and the function of the partition means the width of application to the paper 100 by the foam application roller 232. ing. Accordingly, the pair of partition walls when the application roller 232 is used functions as an application width varying unit.

As described above, the use of the “bubble” type processing agent for the recording medium has a particularly advantageous effect at the time of recording / processing at a high speed as compared with the liquid processing agent.
For example, when printing on continuous paper at a high speed as in a continuous book machine, it is necessary to rotate the roller or the like at high speed in order to catch up with the recording operation.
When such a recording speed exceeds about 100 m / min, the centrifugal force generated by the high-speed rotation of the roller becomes extremely large, and the liquid processing agent is separated from the roller surface and scattered, which is applied to the recording medium. There is a problem that the amount to be reduced is significantly reduced.
In order to solve such problems with a liquid processing agent, it may be possible to increase the viscosity of the liquid and make it difficult to scatter from the roller surface. However, it is difficult to apply such a high viscosity liquid as a thin film. In addition, the load of the liquid supply / drainage operation is large, leading to an increase in the size of the transport pump and the complexity of the apparatus.
On the other hand, “foam” -like treatment agent is a normal low-viscosity liquid during transportation and has a small transportation load, and also exhibits a semi-solid property in the foamed state on the roller. Will not follow and scatter.
Further, as described above, it is advantageous for thin film coating on a recording medium. Further, the remaining bubbles after application can be easily recovered as a low-viscosity liquid by defoaming by heating with a heater or the like, and all problems in high-speed application of liquid treatment agent application can be solved.

Next, a series of processing operation examples of processing agent application control corresponding to the paper size in response to a print command in the image forming apparatus will be described with reference to flowcharts shown in FIGS.
FIG. 12 is a main routine, and FIGS. 13 to 16 are subroutines thereof.
In the conditional branch (S-01) for presence / absence of printing command, if No (hereinafter N), it returns to the original, and if Yes (hereinafter Y), the distance between the front partition 270a and the rear partition 271a is set to the maximum width (for example, The operation of expanding to A3 width (297 mm) shown in FIG. 2B is performed by starting the motor 275 (S-02).
When the HP sensor 276 detects the outer wall surface of the rear partition 271a, it is recognized as HP (S-03).
By obtaining this signal, it can be set by commanding the number of rotations of the motor 275 up to an arbitrary width dimension (in the case of a stepping motor), so that the initialization of the width drive control is executed. Become.

Next, the height of the foam in the foam storage unit 237 is detected by the foam height detection sensor 284, and the amount of foam is detected (measured) by the above calculation method (S-04).
Next, the paper size information to which the processing agent is applied is acquired based on the print command and the input information from the operation unit by the operator (S-05). The width size of the paper size information acquired in (S-05) is Max. If it is (maximum width), a conditional branch is made (S-06). If Y, the process goes to a subroutine (S-09). If N, the next step is executed.
The width size of the paper size information acquired in (S-05) is Max. If the “A width” is smaller than the “maximum width” by the dimension a (S-07), the process branches to a subroutine (S-10), and if N, the next step is executed.
The width size of the paper size information acquired in (S-05) is Max. Conditional branching is made to determine whether the "N width" is smaller by n dimensions than the (maximum width) (S-08). If Y, go to the subroutine (S-11). If N, the next step is executed.

Here, the a dimension, “A width” of (S-07), and the n dimension, “N width” of (S-08) are general values, and are actually A4 side, B5 side,. -It may be a specific dimension such as a postcard size, or from a to n dimensions may be divided by several stages of unequal divisions, or "width dimensions" to which dimensions in equal divisions are applied.
If the answer is No in (S-08), which is the conditional branch of the “width dimension” closest to Min (minimum width), the paper size information acquired in (S-05) in (S-12) The width dimension of Min. It is recognized as (minimum width), and the corresponding subroutine (S-12) is executed.
Next, a conditional branch is made depending on the presence or absence of a print instruction for the next page (S-13). If Y, the process loops to (S-02). If N, the main flow ends.

Next, the subroutines of FIGS. 13 to 16 will be described individually.
FIG. 13 shows the “Max. Width correspondence processing” subroutine of (S-09).
The amount of foam acquired in (S-04) of the main routine is sufficiently applied from the information on the paper width and length (= application area) acquired in the main routine (S-05). Is branched to determine whether the amount is sufficient (S-101). If it is N, the amount of deficiency of bubbles is calculated (S-104), and the deficiency is supplied to the high-pressure air supply unit 221 as the bubble supply means. (S-105).
The amount of stored foam is detected again (S-106), and the process returns to (S-101).
In condition branch Y, the partition wall width is set to Max. The motor 275 is driven until the width is reached (S-102), and the operation of applying the processing agent to the paper is executed (S-103).

FIG. 14 shows the “size A width correspondence processing” subroutine of (S-10).
The amount of foam stored in (S-04) in the main routine is sufficiently applied from the paper width and length (= application area) information acquired in the main routine (S-05). Conditionally branch whether the amount is sufficient (S-111), and if N, calculate the shortage amount of bubbles (S-114), and use the high pressure air supply unit 221 as the bubble supply means to calculate the shortage amount. Supply is performed (S-115). The amount of stored foam is detected again (S-116), and the process returns to (S-111).
In the conditional branch Y, the motor 275 is driven until the partition wall width is set to A dimension (S-112), and the operation of applying the processing agent to the sheet is executed (S-113).
FIG. 15 shows the “size N width corresponding process” subroutine of (S-11).
The amount of foam stored in (S-04) in the main routine is sufficiently applied from the paper width and length (= application area) information acquired in the main routine (S-05). Whether or not the amount is sufficient is branched (S-121). If N, the amount of foam shortage is calculated (S-124), and the shortage is calculated by the high pressure air supply unit 221 serving as the foam supply means. Supply is performed (S-125). The amount of stored foam is detected again (S-126), and the process returns to (S-121).
The motor 275 is driven until the partition width is set to the dimension A in the conditional branch Y (S-122), and the operation of applying the processing agent to the sheet is executed (S-123).

FIG. 16 shows the “size Min. Width correspondence processing” subroutine of (S-12).
The amount of foam stored in (S-04) in the main routine is sufficiently applied from the paper width and length (= application area) information acquired in the main routine (S-05). Whether the amount is sufficient is branched (S-131). If it is N, the amount of foam shortage is calculated (S-134), and the shortage is calculated by the high-pressure air supply unit 221 serving as the foam supply means. Supply is performed (S-135). The amount of stored foam is detected again (S-136), and the process returns to (S-131).
Conditional branch Y reduces the partition width to Min. The motor 275 is driven until the dimensions are obtained (S-132), and the operation of applying the processing agent to the paper is executed (S-133).

Based on FIG. 17, FIG. 18, control of the supply amount to the bubble storage part of the bubble corresponding to the width | variety of a partition is demonstrated.
The upper limit of the supply amount is individually determined based on the value of the output signal of the bubble height detection sensor 284 that changes according to the top position of the third flap (hereinafter referred to as the sensor detection distance).
First, the distance between the partition walls is set to Max. In FIG. 17 (a) showing the state of the above, when the sensor detection distance is long (a value of a specific signal level), the bubble supply is recognized to be full and the supply is stopped and the distance between the partition walls is set to Min. In FIG. 17B showing the state of the above, when the sensor detection distance is short (a value of a specific signal level), the bubble supply is recognized as being full and the supply is stopped.
The distance between the partition walls is Max. From the state of Min. FIG. 18 shows a set value in which the sensor detection distance (signal level) for recognizing that the bubble supply is full while changing to the above state changes from short (high level) to long (low).

The supply amount of the foam supplied to the foam reservoir is controlled to be always constant by changing the supply amount of the foam to the foam reservoir according to the distance between the partition walls.
In other words, “within a predetermined amount range” described in claim 2 or claim 3 means that the control is performed so that individual amounts including the above-described constant amount are obtained.
As described above, the reason for the constant amount is that the partition interval is set to Min. Max. This is not a problem when changing to width, but suddenly Max. From the width Min. This is done so as not to cause a problem that the foam in the foam reservoir overflows when the width needs to be changed.

FIG. 19 shows a “foam supply amount limit value” for calculating the amount of foam supplied from the foam generation means. That is, an additional amount that can be fully filled in the foam storage unit 237 is obtained from the current partition wall width and the foam amount information existing in the current foam storage unit 237 based on the foam height acquired from the foam height detection sensor 284. It is shown that.
In addition, while the supply is started, the amount of foam that is filled every moment is monitored by the foam height detection sensor 284, and control is performed to stop the supply when the limit is reached.

The amount of foam that can be added to the foam reservoir 237 at the point of the current sensor detection distance (signal level = bubble bulk = bubble height) in an arbitrary current partition width in the figure is up to the foam supply amount limit value line. It is calculated as a difference.
Even if the current partition width changes, the sensor detection distance (signal level = bubble height) changes as shown by the alternate long and short dash line, but the amount of foam that can be added is constant. Is shown.
That is, the amount of foam stored in the current foam storage section 237 is naturally constant, and as the partition width changes, if the partition width becomes narrower, the bulk of the bubbles increases accordingly, so the sensor detection distance Although the (signal level) is short (high level), the height of the bubble that can be added up to the limit value of the bubble supply amount in the partition wall width is obtained. The bubble height is a signal level corresponding to the height on the relative sensor signal, not the bubble volume.

FIG. 20 shows another embodiment in which, after fixing the foam partition wall at a position narrower than a desired width, the foam supply is started, the partition wall position is fixed at a predetermined width while gradually expanding, and the foam reservoir is It is a figure for demonstrating a mode that a predetermined amount of bubbles accumulate | store.
That is, as shown in FIG. 20 (a), the initial value of the partition wall width is kept narrow, and the bubble height is increased so that the bubble is not overflowed while the supply of the foam is started and the partition wall width is increased. The flow rate is controlled while being monitored by the height detection sensor 284.
The supply is stopped after reaching the target value of the partition wall width. The timing chart of FIG. 20B shows a state in which the width of the partition wall is increased with the passage of the time axis (X axis) and bubbles are supplied during that time.

FIG. 21 shows a still further embodiment in which “foam supply is started after fixing the foam partition wall at a position narrower than a desired width, and at the same time, information on the current foam amount from the foam amount detection means is acquired. `` Expanding the partition wall stepwise and returning it to a slightly narrower direction, finally fixing the partition wall position with the desired width, and a predetermined amount of foam accumulated in the foam reservoir '' It is a figure for doing.
That is, as shown in FIG. 21 (a), the initial state of the partition wall width is kept narrow, and the bubble height is increased so that the bubble does not overflow while the partition wall width is increased at the same time as the supply of foam is started. The flow rate is controlled while being monitored by the height detection sensor 284.
As shown in the timing chart of FIG. 21 (b), the supply is stopped after finally reaching the target value of the partition wall width while performing the operation of returning the partition wall width slightly in the narrow direction four times during the process. It shows how the partition wall width is increased with the passage of the time axis (X-axis) and bubbles are supplied in the meantime.

Next, an outline of a control unit in this image forming apparatus will be described with reference to a block diagram shown in FIG.
The control unit includes a CPU 801 that performs system control of the image forming apparatus, a ROM 802 that stores information such as programs executed by the CPU 801, particularly a control table, a RAM 803 that is used as a working area, and various settings made by an operator. Operation display unit 804, various sensors 805 for detecting paper size and jam, various motors 806, I / O 807 for outputting control signals to various sensors 805 and various motors 806, etc. The reading control unit 809 that controls the image reading device (scanner) 808, the printing control unit 811 that controls the plotter unit (printing mechanism unit) 810, and the network control device 812 that performs I / F control with the telephone line are also included. Including the communication control unit 813 for performing various facsimile communication controls and the control of the foam coating apparatus 200. And a earthenware pots foam application control unit 814 or the like.
Here, in the various sensors 805, a bubble height detection sensor 284, temperature / humidity detection means for detecting environmental conditions, and whether or not the treatment liquid 201 that can be a foam is present in the container 202 are shown. Contains no liquid end sensing means.
As described above, the CPU 801 as the bubble amount calculation unit and the bubble height detection sensor 284 constitute the bubble amount detection unit of the present invention.

FIG. 23A shows that the amount of foam supplied when the minimum partition wall width is Vmax. When the width is reduced from the maximum partition wall width to the minimum partition wall width by the next printing command in a state that exceeds the (maximum foam storage amount limit), the foam overflows beyond the storage limit, and if this is the case, the outside of the partition wall It shows the state just before the bubbles ooze out.
On the other hand, FIG. 23B shows that the amount of foam supplied when the minimum partition wall width is Vmax. When the width is reduced from the maximum partition width to the minimum partition width by the next printing command in the state set to (Maximum foam storage limit), the foam does not overflow beyond the storage limit as described above. This shows a state where the foam can be supplied stably.
FIG. 24 shows a control table for the amount of foam supply necessary for safely applying the foam without overflowing in the variable range of the partition wall from the maximum partition wall width state to the minimum partition wall state. The vertical (Y) axis indicates the amount (volume) of foam stored, and the horizontal (X) axis indicates the partition width.

V _max. (Maximum foam storage amount limit) is the maximum foam supply amount to prevent bubbles from overflowing from the upper part of the foam storage part even when the width is reduced to the state of the minimum partition wall width in FIG. Show.
In order to prevent the sudden overflow of bubbles, the maximum supply amount of bubbles in the state of the minimum partition wall width becomes V _Nmax (maximum supply amount of bubbles in the minimum partition wall width) in the state of the maximum partition wall width. The maximum supply amount of foam is V _Wmax. The command value is determined with a slight margin so as to be (maximum foam supply amount in the maximum partition wall width).
In addition, since the problem of overflow from the partition wall occurs when the partition wall width is narrowed, V _Wmax. (Maximum amount of foam supply in the maximum partition wall width) is V _Nmax. (Maximum foam supply amount at the minimum partition wall width) or less, the maximum foam supply amount from the maximum partition wall width to the minimum partition wall width is
V _Wmax. To V _Nmax. In the middle of the process of gradually narrowing the partition wall width by controlling the value of the slope connecting up to the supply command value, the flatness of the upper part of the foam reservoir is not maintained V _Nmax. Is considered so that bubbles do not suddenly overflow to the outside of the partition wall _. ≧ V _Wmax. age,
Still further, the V _max. V _max. ≧ V _Nmax. ≧ V _Wmax. It is said.

FIG. 25A shows that the amount of foam supplied when the minimum partition wall width is Vmin. When the width is below the (minimum bubble storage limit) and expanded from the minimum partition wall width to the maximum partition wall width by the next printing command, the bubble storage distribution is depleted in some places. This shows a state in which uneven application is caused by the fact that the supply cannot be performed uniformly.
On the other hand, FIG. 25B shows that the amount of foam supplied when the minimum partition wall width is Vmin. Even when the minimum partition wall width is expanded from the minimum partition wall width to the maximum partition wall width by the next printing command in the state set to (Minimum foam storage amount limit), the storage distribution is not exhausted in some places as described above. This shows a state in which bubbles can be supplied stably without worrying about causing coating unevenness by being able to supply evenly.

FIG. 26 shows a control table of the amount of foam supply necessary for the safe application without depletion of bubbles in the variable range of the partition wall from the minimum partition wall width state to the maximum partition wall width state. The vertical (Y) axis indicates the amount (volume) of stored foam, and the horizontal (X) axis indicates the partition width.
V _min. (Minimum foam storage amount limit) is the minimum supply of foam so that the foam storage distribution can be satisfied without depletion in some places even when widened to the state of the maximum partition wall width of FIG. Indicates the amount.
In order to prevent the sudden depletion of bubbles, the minimum supply amount of bubbles in the state of the minimum partition wall width is V _Nmin. The minimum amount of foam supply in the state of the maximum partition wall width is V _Wmin. The command value is determined with a slight margin so as to be (the minimum bubble supply amount in the maximum partition wall width).
Moreover, since the problem of depletion occurs when the partition width widens,
V _Wmin. (Minimum foam supply amount in the maximum partition wall width) is V _Nmin. (Minimum bubble supply amount at minimum partition wall width) or more, and the maximum supply amount of bubbles from the maximum partition wall width to the minimum partition wall width is V _Wmin. To V _Nmin. In the middle of the process of gradually narrowing the partition wall width by controlling the value of the slope connecting up to the supply command value, the flatness of the upper part of the foam reservoir is not maintained V _{Nmin. In} consideration that the bubble distribution is not suddenly interrupted and exhausted _. ≦ V _Wmin. age,
Furthermore, the V _min. In consideration of the relationship with V _min. ≦ V _Nmin. ≦ V _Wmin. It is said.

  In the above embodiment, the foam application device is described as applying foam to the paper before image formation. However, the foam application device is arranged on the downstream side of the recording head unit to perform image formation. It can also be set as the structure which apply | coats a bubble on a paper.

  Moreover, although the said embodiment demonstrated in the example which produces | generates and apply | coats foam from the liquid which can be made into a foam state, this invention produces | generates foam from the gel which can be made into a foam state. The present invention can also be applied to an apparatus for applying to a member to be applied and an image forming apparatus provided with this apparatus.

  The foam coating apparatus according to the present invention can also be applied to, for example, an electrophotographic image forming apparatus. For example, without disturbing fine particles containing a resin such as toner on a medium such as paper, and applying a foamed fixer (hereinafter referred to as “fixing bubbles”) to the medium to which the fine resin particles are adhered, 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 in which resin fine particles are quickly fixed on a medium after coating and no residual oil feeling is generated on the medium.

  That is, the fixing solution is in the form of bubbles containing bubbles, and the film thickness of the fixing foam layer is controlled in accordance with the applied pressure, so that toner offset and image flow to the contact application means such as an application roller can be reduced. It is possible to prevent and fix by extremely minute application. Further, the resin fine particles are highly effective for the toner fine particles used in the electrophotographic technology, and offset and image flow can be prevented by controlling the film thickness of the fixing foam layer according to the layer thickness of the resin fine particles.

DESCRIPTION OF SYMBOLS 100 Paper as recording medium 200 Foam application apparatus as foam application unit 201 Treatment liquid as liquid 205 First bubble generation unit as bubble generation unit 207 Second bubble generation unit as bubble generation unit 208 Bubble as application unit Application part 210 Foam 237 Foam storage part 250 Extension part 270a Front partition 271a as partition member 271a Rear partition 284 as partition member 284 Bubble height detection sensor as bubble height detection means

Claims (9)

In an image forming apparatus for forming an image on a recording medium,
A foam application means for applying, as a processing agent or a fixing agent, a foam in which at least one of a liquid and a gel is foamed to a recording medium or an intermediate member to be applied to the recording medium;
The foam applying means includes foam generating means for generating the foam;
An extending section that extends the foam in the width direction of the recording medium perpendicular to the conveyance direction of the recording medium when supplying the foam from the foam generation means to the coating means;
Application means for applying the foam supplied from the foam generating means to the recording medium or the intermediate member through the extending portion ;
A foam storage section that is formed in the application area of the application means and stores the foam supplied from the foam generation means;
Foam amount detection means for detecting the amount of foam stored in the foam storage unit;
Have
An image forming apparatus, wherein the amount of foam supplied from the foam generation unit is controlled based on information on the amount of foam by the bubble amount detection unit. The image forming apparatus according to claim 1.
A supply width variable means capable of changing a supply width in the recording medium width direction of the foam supplied from the foam generation means to the coating means;
The command value of the amount of foam supplied from the foam generation means is set so that the amount of foam stored in the foam storage section is within a predetermined amount range between the minimum width and the maximum width of the supply width variable means. An image forming apparatus that performs control to determine . The image forming apparatus according to claim 1 .
An application width variable means capable of changing the application width in the width direction of the recording medium of the bubbles supplied from the foam generation means to the application means;
The foam amount command value supplied from the foam generating means is set so that the amount of foam stored in the foam storage section is within a predetermined range between the minimum width and the maximum width of the application width varying means. An image forming apparatus that performs control to determine . The image forming apparatus according to claim 2 or 3 ,
The foam amount detection means is a foam height detection means for detecting the foam height of the foam reservoir in a non-contact manner,
Bubble amount calculation for calculating the amount of foam to be supplied from the bubble generating means from the relationship between the bubble height detected by the bubble height detecting means and the width information of the supply width variable means or the application width variable means. Means,
An image forming apparatus characterized in that it has a. The image forming apparatus according to claim 2 or 3 ,
Having a foam height detection plate that is displaced according to the foam height of the foam reservoir,
The image forming apparatus, wherein the bubble height detecting means detects the position of the bubble height detecting plate as the bubble height . The image forming apparatus according to claim 2 ,
The supply width varying means or the coating width varying means has a pair of partition members that are capable of moving the bubble storage portion in opposite directions in the recording medium width direction, and the pair of partition members has a desired width. After fixing, a predetermined amount of bubbles accumulated in the bubble storage unit is detected based on information from the bubble amount detecting means, and a command value for the amount of bubbles supplied from the bubble generating means is determined. An image forming apparatus that performs feedback control . The image forming apparatus according to claim 2 ,
The supply width varying means or the coating width varying means has a pair of partition members that are capable of moving the bubble storage portion in opposite directions to each other in the recording medium width direction, and the pair of partition members has a desired width. After fixing in a narrow position, the supply of foam is started, the pair of partition members are fixed with a predetermined width while gradually expanding, and the amount of foam is detected when a predetermined amount of foam is accumulated in the foam reservoir An image forming apparatus that performs feedback control that detects based on information from the means and determines a command value for the amount of foam supplied from the foam generating means . The image forming apparatus according to claim 2 ,
The supply width varying means or the coating width varying means has a pair of partition members that are capable of moving the bubble storage portion in opposite directions in the recording medium width direction, and the pair of partition members is narrower than a desired width. After fixing the position, the foam supply is started, and at the same time, while acquiring the foam amount information from the foam amount detection means, the pair of partition members are expanded stepwise and returned to a slightly narrowing direction. Specifically, the position of the pair of partition members is fixed at a desired width, and the foam generation is detected based on information from the foam amount detection means that a predetermined amount of foam is accumulated in the foam reservoir. An image forming apparatus characterized by performing feedback control for determining a command value of a supply amount of bubbles supplied from the means . The image forming apparatus according to claim 2 ,
The supply width varying means or the coating width varying means has a pair of partition members that are capable of moving the bubble reservoir in opposite directions to each other in the recording medium width direction,
There is a print command, and in the step immediately before image formation, the amount of foam stored in the pair of partition members is acquired from the foam amount detection means,
The pair of partition members are moved to a width in accordance with a print command, and after calculating and calculating the excess and deficiency of bubbles with respect to a desired amount of the width, the pair of partition members are moved, and the excess and deficiency of bubbles An image forming apparatus, wherein feedback control is performed to determine a command value of a supply amount of bubbles supplied from the bubble generation unit based on a calculated value .

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