JP2015229300A - Liquid storage container and liquid application device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid storage container which can prevent false detection of a sensor which detects the residual quantity of the liquid contained in a container.SOLUTION: A liquid storage container containing liquid to be applied to an object includes sensors 210a, 210b which detect the residual quantity of the liquid on the basis of contact or no contact with the liquid. The sensors are provided to project in perpendicular direction with respect to the liquid level of the liquid within the liquid storage container. The surface of the inside of the liquid storage container from which the sensor protrudes has such shape that the liquid does not remain on the surface.

Description

  The present invention relates to a liquid storage container and a liquid application device, and more particularly to reduction of erroneous detection of a sensor that detects the remaining amount of liquid stored in the liquid storage container.

  In recent years, there has been a tendency to digitize information, and image processing apparatuses such as printers and facsimiles used for outputting digitized information and scanners used for digitizing documents have become indispensable devices. Such an image processing apparatus is often configured as a multifunction machine that can be used as a printer, a facsimile, a scanner, or a copier by providing an imaging function, an image forming function, a communication function, and the like.

  Among such image processing apparatuses, image forming apparatuses used for outputting digitized documents improve printing quality by avoiding conditions that affect printing quality such as bleeding, density fluctuation, color tone fluctuation, and show-through. Therefore, a technique of applying a treatment liquid for aggregating the color material of the ink by pretreatment is generally known.

  Since such a processing liquid is put in a container and the processing liquid is supplied from the container and consumed during the above-described pretreatment, it is necessary to replenish the container with the processing liquid as needed. As one aspect thereof, a method is known in which a voltage is applied between electrode pins of a conductor and the remaining amount of liquid is detected by a resistance value.

  In the detection using such an electrode, for the purpose of accurately detecting the remaining amount of ink, the ink resistance value for each environmental temperature is stored, and the detection voltage applied to the ink is less than the electrolysis voltage. Setting has been proposed (see, for example, Patent Document 1).

  The sensor using the electrode as described above is a contact type, and when the electrode placed in the direction perpendicular to the liquid level of the processing liquid placed in the container and the processing liquid are in contact, It is detected that the remaining amount is not less than a predetermined amount. In addition, when the processing liquid is consumed and the liquid level is lowered, and the electrode and the liquid level are not in contact with each other, it is detected that the remaining amount of the processing liquid is less than a predetermined amount.

  However, when the processing liquid contained in the container is consumed and the height of the liquid level decreases, the liquid remains on the wall surface depending on the condition of the liquid on the wall surface inside the container, and the liquid film is formed on the wall surface inside the container. May be stretched. When a liquid film is stretched on the inner wall of the container holding the electrode used for the sensor as described above, the resistance value changes depending on the state of the liquid film, and the electrode and the liquid surface of the processing liquid contact each other. In spite of this, it may be detected that the electrode and the processing liquid are in contact with each other, and the remaining amount of the processing liquid may be erroneously detected.

  In the technique disclosed in Patent Document 1, the influence of the liquid film stretched inside the container containing the processing liquid is not considered. Such a problem is not limited to the container containing the processing liquid in the image forming apparatus, and may occur in the same manner as long as the container contains the liquid in the liquid application apparatus that supplies and applies the liquid.

  The present invention has been made to solve such a problem, and an object thereof is to reduce erroneous detection of a sensor that detects the remaining amount of liquid contained in a container.

  In order to solve the above-described problem, an aspect of the present invention is a liquid storage container in which a liquid to be applied to an object is stored, and the remaining amount of the liquid based on the presence or absence of contact with the liquid The sensor is provided so as to protrude in a direction perpendicular to the liquid level of the liquid inside the liquid container, and the surface inside the liquid container that the sensor protrudes from the surface. It has a shape that prevents the liquid from remaining.

  ADVANTAGE OF THE INVENTION According to this invention, the misdetection of the sensor which detects the residual amount of the liquid accommodated in the container can be reduced.

1 is a diagram illustrating an overall configuration of an image forming system including a pretreatment liquid coating apparatus according to an embodiment of the present invention. It is a figure which shows the structure of the pre-processing liquid coating device which concerns on embodiment of this invention. It is a figure which illustrates a part of general reserve tank, and the structure of a sensor. It is a graph which illustrates the change of the output of the sensor according to the residual amount of the processing liquid in the reserve tank of the composition shown in FIG. It is a figure which shows an example of a structure of the reserve tank which concerns on embodiment of this invention. It is a figure which illustrates the change of the output of the sensor according to the residual amount of the processing liquid in the reserve tank shown in Drawing 5 concerning the embodiment of the present invention. It is a figure which shows another example of a structure of the reserve tank which concerns on embodiment of this invention. It is a figure which shows another example of a structure of the reserve tank which concerns on embodiment of this invention. It is a figure which shows another example of a structure of the reserve tank which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, an image forming system including an ink jet type image forming apparatus using roll paper will be described with a liquid application device that applies a liquid on a paper surface before image formation output by the image forming apparatus.

  FIG. 1 is a diagram illustrating a configuration of the entire image forming system according to the present embodiment. As shown in FIG. 1, the image forming system according to the present embodiment applies a liquid to the surface of the roll paper S sent out from the preprocessing machine 1 and the preprocessing machine 1 that feeds the roll paper S wound in a roll shape. The pretreatment liquid coating device 2, the inkjet printer main body 3 that forms an image by discharging the color material onto the roll paper coated with the liquid by the pretreatment liquid coating device 2, and the paper on which the image is formed is wound up A processor 4 is included. That is, in the present embodiment, the pretreatment liquid coating apparatus 2 functions as a liquid coating apparatus.

  In the configuration shown in FIG. 1, the gist of the present embodiment is the configuration of a liquid storage container that stores a liquid to be applied to the roll paper surface in the pretreatment liquid coating apparatus 2. In the pretreatment liquid coating apparatus 2, a treatment liquid that is a modifier for modifying the surface of the roll paper S is applied to the roll paper. When the treatment liquid is applied to the entire surface of the roll paper S, the moisture of the ink discharged onto the surface of the roll paper S in the inkjet printer main body 3 quickly permeates the roll paper S and the color component increases in viscosity. In the present embodiment, a roll paper is described as an example to which the treatment liquid is applied by the pretreatment liquid application apparatus 2, but the material is not limited to paper, and a film, a plastic sheet, or the like may be used.

  Next, the configuration of the pretreatment liquid coating apparatus 2 according to this embodiment will be described with reference to FIG. As shown in FIG. 2, the pretreatment liquid coating apparatus 2 according to the present embodiment performs processing on the coating unit 200 and the coating unit 200 that apply the processing liquid to the roll paper 205 that is the object in the transport path of the roll paper 205. It includes a reserve tank 224 and cartridges 229 and 238 which are supply units for supplying liquid.

  Further, the application unit 200 includes a cylindrical application roller 201 that applies the processing liquid, a squeeze roller 202 that thins the processing liquid and transfers it to the application roller 201, and a pressure roller that sandwiches the roll paper 205 between the application roller 201. 203. The squeeze roller 202 is immersed in the processing liquid in the supply pan 204 for storing the processing liquid, and the liquid level is controlled by a liquid level detection sensor that detects the amount of liquid in the supply pan 204 (not shown). So that the coating amount is constant.

  The supply pan 204 is formed so as to cover the application roller 201, and suppresses evaporation of the processing liquid in the supply pan 204. However, the pressure contact portion between the application roller 201 and the pressure roller 203 needs to be opened, and is not a complete sealed system.

  Therefore, a substantially sealed reserve tank 224 is provided in the supply unit. When the solenoid valve 226 provided in the retraction path 225 that communicates the reserve tank 224 and the supply pan 204 is opened, the processing liquid in the supply pan 204 is transferred to the reserve tank 224 through the retraction path 225 due to a water head difference. The With such a configuration, an increase in the viscosity of the treatment liquid can be suppressed.

  Note that when the electromagnetic valve 226 is opened, for example, the printing process is stopped for a time (for example, 1 hour or more) longer than the work time between normal print jobs such as replacement of the roll paper 205 and change of the print pattern. In this case, the waiting time for filling the supply liquid into the supply pan 204 does not occur every time printing is stopped.

  Further, since the electromagnetic valve 226 is opened when power is not supplied, the processing liquid stored in the supply pan 204 is transferred to the reserve tank 224 when the power of the pretreatment liquid coating apparatus 2 is shut off. The With such a configuration, the processing liquid is prevented from remaining in the supply pan 204 for a long time.

  Also, in the reserve tank 224, when the processing liquid has not been used for a long time (for example, several tens of days or more), the viscosity of the processing liquid increases. Therefore, when the processing liquid has not been used in the reserve tank 224 for a certain period of time, the processing liquid in the reserve tank 224 is discharged into the waste liquid tank 221 by the waste liquid pump 222, so that the freshness of the processing liquid is maintained.

  Further, a circulation path 228 communicating from the retreat path 225 to the filter 227 is branched. In this circulation path 228, an electromagnetic valve 232 is provided on the upstream side of the filter 227, and a three-way valve 233 is provided on the downstream side. The filter 227 removes paper dust and the like remaining in the supply pan 204 and prevents the processing liquid from becoming pasty. Note that paper dust or the like staying in the supply pan 204 is generated when the roll paper 205 is slid and moved by the application roller 201 and the pressure roller 203 (sliding).

  When the electromagnetic valve 232 is appropriately opened while applying the processing liquid, a part of the processing liquid in the supply pan 204 is passed through the retreat path 225 and the circulation path 228 to the filter 227. Paper dust contained in the treatment liquid is removed. When the three-way valve 233 is brought into communication with the filter 227 and the supply pan 204 and the supply pump 230 is driven, the processing liquid from which the paper dust has been removed by the filter 227 is supplied to the supply pan 204 by the supply pump 230. The

  The supply of the processing liquid to the supply pan 204 is performed from the reserve tank 224 or the cartridges 229 and 238 which are supply units. The reserve tank 224 is provided with a sensor 210 that detects the remaining amount of the processing liquid in the reserve tank 224.

  The sensor 210 is composed of two electrode pins, and detects the remaining amount of the processing liquid in the reserve tank 224 that is a liquid storage container in which a liquid is stored by a current that flows when a voltage is applied between the electrode pins. . The configuration of the reserve tank 224 for reducing such erroneous detection of the remaining amount of the processing liquid by the sensor 210 is the gist according to the present embodiment. Details will be described later.

  When the sensor 210 detects that the remaining amount of processing liquid in the reserve tank 224 is greater than or equal to a predetermined amount, the electromagnetic valve 236 is opened and the processing liquid stored in the reserve tank 224 is stored in the reserve tank 224. And a filter 227 from a circulation supply path 235 that communicates with the filter 227. When the three-way valve 233 is brought into a state where the filter 227 and the supply pan 204 communicate with each other and the supply pump 230 is driven, the processing liquid passed through the filter 227 is supplied to the supply pan 204 by the supply pump 230.

  On the other hand, when the sensor 210 detects that the remaining amount of the processing liquid in the reserve tank 224 is less than a predetermined amount, the supply is performed from one of the cartridges 229 and 238. For example, when the supply from the cartridge 229 is performed, when the electromagnetic valve 234 is opened, the three-way valve 233 is brought into communication with the cartridge 229 and the supply pan 204, and the supply pump 230 is driven, the processing stored in the cartridge 229 is performed. The liquid is supplied to the supply pan 204 by the supply pump 230 through the path 231.

  Further, an EMPTY sensor 223 that detects the presence or absence of the processing liquid in the cartridges 229 and 238 is provided on the path 231. For example, when it is detected that there is no processing liquid in the cartridge 229, the control is switched to supply from the cartridge 238. As a result, the electromagnetic valve 237 is opened, and the processing liquid contained in the cartridge 238 is supplied to the supply pan 204 by the supply pump 230 through the path 231.

  Meanwhile, the cartridge 229 detected as having no processing liquid is replaced with a new cartridge. As described above, the configuration in which a plurality of cartridges can be mounted makes it possible to replace the cartridges without stopping the operation of the pretreatment liquid coating apparatus 2. In the present embodiment, the case where two cartridges 229 and 238 are mounted has been described as an example. However, this is an example, and three or more cartridges may be mounted.

  Next, the configuration of a general reserve tank 224 will be described. FIG. 3 is a diagram illustrating a configuration of a part of a general reserve tank 224 and a sensor 210 provided in the reserve tank 224. FIG. 3 illustrates a cross section of the reserve tank 224. As shown in FIG. 3, the sensor 210 includes two electrode pins 210a and 210b held in an insulator case. Further, as shown in FIG. 3, the sensor 210 is provided in the reserve tank 224 so as to protrude in a direction perpendicular to the liquid level.

  An alternating current is applied to one electrode pin (here, electrode pin 210a), and the other electrode pin (here, electrode pin 210b) is GND. As shown in FIG. 3A, when the electrode pins 210a and 210b are immersed in the processing liquid (represented by dots in FIG. 3) in the reserve tank 224, charge transfer is performed by ions in the liquid. Thus, the sensor 210 can obtain an output corresponding to the flowed electric charge.

  FIG. 4 is a graph illustrating the change in the output of the sensor 210 according to the remaining amount of the processing liquid in the reserve tank 224 having the configuration shown in FIG. As shown in FIG. 4, the horizontal axis indicates the elapsed time (seconds), and the vertical axis indicates the output value of the sensor 210 (hereinafter referred to as “sensor output value”) (V).

  It is assumed that the processing liquid decreases as time elapses from the state where the processing liquid is sufficiently contained in the reserve tank 224. When the processing liquid is sufficiently contained in the reserve tank 224 and the electrode pins 210a and 210b are completely immersed in the processing liquid (for example, between the elapsed time 0 seconds and 25 seconds shown in FIG. 4), the sensor output The value is approximately 0V.

  As the processing liquid decreases, the height of the liquid level in the reserve tank 224 decreases, so that the electrode pins 210a and 210b and the liquid level of the processing liquid are eventually separated as shown in FIG. 3B. . In this case, since there is no contact between the electrode pins 210a and 210b and the processing liquid, the sensor output value is 0 V and the remaining amount of the processing liquid is insufficient at the timing when the electrode pins 210a and 210b are separated from the liquid surface. It changes to a value (for example, 2V) larger than the threshold value (slice level) to detect. Thus, the sensor 210 detects the remaining amount of liquid based on the presence or absence of contact with the liquid.

  However, when the configuration of the reserve tank 224 is the configuration shown in FIG. 3, as shown in FIG. 3B, the surface inside the reserve tank 224 (inside the liquid container) that holds the electrode pins 210a and 210b (FIG. 3). In the reserve tank 224 shown in FIG. 5, the liquid remains on the “top surface”), and a liquid film is stretched on the top surface.

  Since the resistance value changes due to the influence of the liquid film, even if the electrode pins 210a and 210b and the liquid surface are separated from each other, the rise of the sensor output value becomes dull. In FIG. 6, a lag (for example, about 15 seconds in the graph shown in FIG. 4) occurs at a timing until it exceeds the 1 V line indicated by a dotted line. Therefore, although the electrode pins 210a and 210b are separated from the liquid surface, it is erroneously detected that the remaining amount of the processing liquid in the reserve tank 224 is greater than or equal to a predetermined amount.

  The configuration of the reserve tank 224 for reducing such erroneous detection is the gist of the present embodiment. Hereinafter, the configuration of the reserve tank 224 according to the present embodiment will be described.

  FIG. 5 is a diagram illustrating an example of the configuration of the reserve tank 224 according to the present embodiment. FIG. 5 shows a part of a cross section when the reserve tank 224 shown in FIG. 2 is cut in front of the sensor 210 in the direction A. As shown in FIG. 5, the reserve tank 224 is provided with a wall surface at a position lower than the top surface holding the electrode pins 210a and 210b. That is, the surface inside the reserve tank 224 from which the sensor 210 protrudes has a U-shape in which the liquid surface of the processing liquid faces the opening.

  With such a configuration, even when the treatment liquid is sufficiently placed in the reserve tank 224, as shown in FIG. 5A, the top surface where the electrode pins 210a and 210b are held is provided. An air layer remains and the processing liquid does not come into contact.

  Therefore, when the liquid level of the processing liquid in the reserve tank 224 decreases and the electrode pins 201a and 210b are separated from the liquid level, a liquid film is formed on the top surface as shown in FIG. It is never stretched.

  FIG. 6 is a graph illustrating the change in the output of the sensor 210 according to the remaining amount of the processing liquid in the reserve tank 224 having the configuration shown in FIG. As shown in FIG. 6, the configuration of the vertical axis and the horizontal axis is the same as the configuration shown in FIG. As described above, in the configuration of the reserve tank 224 shown in FIG. 5, when the electrode pins 210a and 210b are separated from the liquid surface, no liquid film is stretched on the top surface. The value is not affected by the liquid film, and the electrode pins 210a and 210b are completely insulated.

  Therefore, as shown in FIG. 6, at the timing when the electrode pins 210a and 210b are separated from the liquid surface, the sensor output value immediately rises from 0V to 2V, and the sensor 210 has a remaining amount of processing liquid in the reserve tank 224. Correctly detect if it is missing.

  In the present embodiment, the case where the opening has a U-shape facing the liquid surface of the processing liquid as illustrated in FIG. 5 has been described as an example. However, this is only an example, and the shape of the U-shaped corner with rounded corners, trapezoidal shape, dome shape, etc. is a shape that prevents the processing liquid from coming into contact with the top surface holding the electrode pins 210a, 210b. I just need it.

  Next, another example of the configuration of the reserve tank 224 according to this embodiment will be described. FIG. 7 is a diagram illustrating another example of the configuration of the reserve tank 224 according to the present embodiment. As shown in FIG. 7, the top surface holding the electrode pins 210a and 210b of the reserve tank 224 is inclined (for example, 5 °) with respect to the liquid surface of the processing liquid and in the horizontal direction.

  With such a configuration, when the liquid level of the processing liquid in the reserve tank 224 is lowered, the liquid remaining on the top surface is transferred to the wall surface on the electrode pin 210b side as shown in FIG. And flow down along the wall. That is, in the configuration of the reserve tank 224 shown in FIG. 7, when the electrode pins 210a and 210b are separated from the liquid surface, the liquid remaining on the top surface is less than that in the configuration shown in FIG.

  Therefore, at the timing when the electrode pins 210a and 210b are separated from the liquid surface, the sensor output value is less affected by the liquid film stretched on the top surface, and the remaining amount of the processing liquid in the reserve tank 224 is determined in advance. It is possible to reduce false detection of the amount exceeding the specified amount.

  Next, another example of the configuration of the reserve tank 224 according to the present embodiment will be described. 8 and 9 are diagrams showing still another example of the configuration of the reserve tank 224 according to the present embodiment. FIGS. 8A and 9A are cross-sectional views as seen from the direction in which the reserve tank 224 shown in FIGS. 8B and 9B is rotated 90 degrees clockwise.

  As shown in FIGS. 8A and 9A, the top surface holding the electrode pins 210a and 210b of the reserve tank 224 has a dome shape (semicircular shape) with respect to the liquid level of the processing liquid. It is the shape. With such a configuration, when the liquid level of the processing liquid in the reserve tank 224 is lowered, the liquid remaining on the top surface is lowered along the wall surface of the top surface as shown in FIG. To flow. That is, in the configuration of the reserve tank 224 shown in FIGS. 8 and 9, when the electrode pins 210a and 210b are separated from the liquid surface, the amount of liquid remaining on the top surface is smaller than that in the configuration shown in FIG. Thus, as shown in FIG. 9B, the liquid film stretched on the top surface is thinner than in the case of the configuration shown in FIG.

  Therefore, at the timing when the electrode pins 210a and 210b are separated from the liquid surface, the sensor output value is less affected by the liquid film stretched on the top surface, and the remaining amount of the processing liquid in the reserve tank 224 is determined in advance. It is possible to reduce false detection of the amount exceeding the specified amount.

  In the reserve tank 224 shown in FIG. 9, the case where the electrode pins 210a and 210b are held at the highest point which is the highest position of the semicircular shape is described as an example. With such a configuration, since the electrode pins 210a and 210b are held at a position where the liquid hardly remains, erroneous detection of the remaining amount of the processing liquid by the sensor 210 can be further reduced. However, this configuration is not essential, and the electrode pins 210a and 210b may be held at positions shifted from the uppermost point.

  As described above, the reserve tank 224 of the pretreatment liquid coating apparatus 2 according to the present embodiment has a treatment liquid on the surface holding the sensor 210 when the liquid level is lowered due to a decrease in the treatment liquid. The shape prevents it from remaining. With such a configuration, the sensor output value when the electrode pins 210a and 210b of the sensor 210 and the liquid surface of the processing liquid are separated from each other influences the influence of the liquid film stretched on the top surface holding the sensor 210 as compared with the conventional case. Since it can make it hard to receive, it becomes possible to reduce the misdetection of the sensor which detects the residual amount of the liquid accommodated in the liquid container.

  The present embodiment is not limited to the reserve tank 224 that is a container containing processing liquid in the image forming apparatus, but can be similarly applied to a container that contains liquid in a liquid application apparatus that supplies and applies liquid. It is.

DESCRIPTION OF SYMBOLS 1 Pre-processing machine 2 Pre-processing liquid coating device 3 Inkjet printer main body 4 Post-processing machine 200 Application part 201 Application roller 202 Squeeze roller 203 Pressure roller 204 Supply pan 205 Roll paper 210 Sensor 221 Waste liquid tank 222 Waste liquid pump 223 EMPTY sensor 224 Reserve Tank 225 Retreat path 226, 232, 234, 236, 237 Solenoid valve 227 Filter 228 Circulation path 229, 238 Cartridge 230 Supply pump 231 path 233 Three-way valve 235 Circulation supply path

Japanese Patent Laid-Open No. 06-270410

Claims (7)

A liquid storage container in which a liquid to be applied to an object is stored;
A sensor for detecting the remaining amount of the liquid based on the presence or absence of contact with the liquid;
The sensor is provided so as to protrude in a direction perpendicular to the liquid level of the liquid inside the liquid container,
A surface inside the liquid storage container from which the sensor protrudes has a shape that prevents the liquid from remaining on the surface. The liquid storage container according to claim 1, wherein a surface inside the liquid storage container from which the sensor protrudes has a shape that prevents the liquid from coming into contact with the surface. The liquid storage container according to claim 2, wherein the surface inside the liquid storage container from which the sensor protrudes has a U-shape in which the liquid surface of the liquid faces the opening. The liquid storage container according to claim 1, wherein a surface inside the liquid storage container from which the sensor protrudes has a shape inclined with respect to a horizontal direction of the liquid surface of the liquid. 2. The liquid container according to claim 1, wherein a surface inside the liquid container from which the sensor protrudes has a semicircular shape with respect to a horizontal direction of the liquid surface of the liquid. The liquid container according to claim 5, wherein the sensor protrudes from the highest position of the semicircular surface.   A liquid coating apparatus comprising the liquid container according to claim 1.