JP2013230595A - Liquid storage tank, liquid ejection head unit, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problem that the whole filter cannot be effectively used, in which stagnation of liquid is generated in a head tank, thus, a dimension of the filter is enlarged.SOLUTION: A storage part 42 of a head tank 4 is divided into a filter upstream chamber 42A and a filter downstream chamber 42B by a filter 43 that filters liquid. The upper part includes: an inflow port 45 in which the liquid is flown from the outside; and an inflow passage 46 that guides the liquid flown in from the inflow port 45 to the lower part of the filter upstream chamber 45B. The lower part includes: a supply port 51 that supplies the liquid to the head 2; and an outflow passage 52 that guides the liquid to the supply port 51 from the upper part of the filter downstream chamber 42B. An opening 46a being the exit with respect to the filter upstream chamber 42A of the inflow passage 46 and an opening 52a being the entrance to the outflow passage 52 of the filter downstream chamber 42B are arranged to be diagonal to the storage part 22 that is substantially rectangular.

Description

  The present invention relates to a liquid storage tank, a liquid discharge head unit, and an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming using a recording head composed of a liquid discharge head (droplet discharge head) that discharges ink droplets. As an apparatus, an ink jet recording apparatus or the like is known.

  As an ink supply method in an ink jet recording apparatus used as an image forming apparatus, a head tank (sub tank, buffer tank, etc.) is arranged on the recording head side, and a main tank is arranged on the apparatus main body side. A system is known in which ink is replenished and supplied from the main tank to the head tank, and ink is supplied from the head tank to the recording head.

  As a conventional head tank, for example, the storage section of the head tank is divided into an upstream chamber and a downstream chamber by a filter member arranged in a direction along the droplet discharge direction, and a liquid is introduced from the upper portion of the upstream chamber. A device in which the liquid of the head is supplied from the lower part is known (Patent Document 1).

JP 2011-148101A

  However, as described above, when the liquid is introduced from the upper part of the storage part of the head tank and the liquid is supplied to the head from the lower part of the storage part, stagnation occurs in the flow of liquid in the storage part, and the entire filter Cannot be used effectively, and there is a problem that the filter area increases.

  The present invention has been made in view of the above-described problems, and an object thereof is to reduce stagnation in a liquid storage tank.

In order to solve the above problems, the liquid storage tank according to the present invention is:
A liquid storage tank for supplying a liquid to be supplied to a head for discharging droplets,
A storage portion for storing the liquid is formed in the tank body,
The container is divided into a filter upstream chamber and a filter downstream chamber by a filter for filtering the liquid,
An inflow port provided in the upper part of the tank body, through which the liquid flows from the outside,
An inflow path for guiding the liquid flowing in from the inflow port to a lower portion of the filter upstream chamber;
A supply port for supplying the liquid to the head provided at a lower portion of the tank body; and an outflow path for guiding the liquid from the upper portion of the filter downstream chamber to the supply port;
An outlet of the inflow path with respect to the filter upstream chamber and an inlet of the filter downstream chamber to the outflow path are arranged at diagonal positions of the accommodating portion having a substantially rectangular shape.

  According to the present invention, generation of liquid stagnation in the liquid storage tank can be reduced.

It is explanatory drawing of the ink supply system in 1st Embodiment of this invention. It is front explanatory drawing of the head tank of FIG. It is a cross-sectional explanatory drawing of the head tank. It is side sectional explanatory drawing along the perpendicular direction of the head tank which concerns on 2nd Embodiment of this invention. It is a plane cross-sectional explanatory drawing along a horizontal direction similarly. It is a perspective explanatory view of a head tank concerning a 3rd embodiment of the present invention. It is a plane cross-sectional explanatory drawing along a horizontal direction similarly. It is front explanatory drawing of the head tank which concerns on 4th Embodiment of this invention. FIG. 9 is a cross-sectional explanatory diagram along AA in FIG. 8. It is front explanatory drawing of the head tank which concerns on 5th Embodiment of this invention. It is sectional explanatory drawing which follows BB of FIG. It is principal part expansion explanatory drawing with which description of the example of a metal mold | die when forming a discharge port is provided. 1 is an overall configuration diagram of an example of an image forming apparatus according to the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. A first embodiment of the present invention will be described with reference to FIGS. 1 is an explanatory diagram of an ink supply system in the embodiment, FIG. 2 is a front explanatory diagram of the head tank of FIG. 1, and FIG. 3 is an explanatory plan view of the head tank. It is.

  A liquid discharge head unit (hereinafter also simply referred to as “head unit”) 1 includes a head 2 that discharges droplets and a head tank (hereinafter referred to as a liquid storage tank) according to the present invention that stores ink to be supplied to the head 2. , Also simply referred to as “tank”) 4.

  In the head tank 4, a storage portion 42, which is a substantially rectangular liquid storage chamber for storing ink, which is a liquid supplied to the head 2, is formed in a tank case 41 that is a tank body. A filter 43 for filtering ink is arranged in the storage portion 42 in the vertical direction, and the storage portion 42 is divided into a filter upstream chamber 42A and a filter downstream chamber 42B.

  One wall surface of the filter upstream chamber 42A of the accommodating portion 42 is closed by a film member 44, which is a member that can be bent, attached to the tank case 41 so as to absorb pressure fluctuations. Yes.

  Here, an inflow port 45 through which ink flows from the outside is provided in the upper part of the tank case 41. The main tank 5 is connected to the inflow port 45 via the liquid supply path 6, and ink is supplied from the main tank 5 via the liquid supply path 6.

  An inflow path 46 that guides ink flowing from the inflow port 45 to the lower portion of the filter upstream chamber 42A is provided on one side of the tank case 41. The inflow path 46 is partitioned from the filter upstream chamber 42A by a partition wall portion 47 formed integrally with the tank case 41 in the vertical direction (vertical direction).

  An opening 46a serving as an outlet for supplying ink to the filter upstream chamber 42A is provided between the lower end portion of the partition wall portion 47 and the bottom surface 42a of the storage portion 42.

  A bubble discharge path 49 is provided between the upper end portion of the partition wall portion 47 and the top surface 42 b of the accommodating portion 42.

  On the other hand, a supply port 51 that supplies ink to the head 2 is provided below the tank case 41. The other side of the tank case 41 is provided with an outflow path 52 that guides ink from the upper part of the filter downstream chamber 42 </ b> B to the supply port 51.

  Here, the opening 46 a that is the outlet of the inflow path 46 and the opening 52 a that is the inlet of the outflow path 52 are arranged at diagonal positions of the accommodating portion 42 that has a substantially rectangular shape. That is, the liquid is supplied to the filter upstream chamber 42A from the lower (bottom) side of the filter upstream chamber 42A of the housing portion 42, and the liquid is supplied to the head 2 from the upper side of the filter downstream chamber 42B.

  In addition, a discharge port 61 is provided on the upper side of the tank case 41 on the side opposite to the inlet port 45 side of the filter upstream chamber 42A, and the top surface 42b of the filter upstream chamber 42A extends from the inlet port 45 side to the outlet port 61 side. The inclined surface becomes higher. Thereby, the bubbles are guided to the discharge port 61 side by the top surface 42b.

  The discharge port 61 is connected to the main tank 5 via the return path 7.

  With this configuration, the ink flowing in from the inflow port 45 is guided to the lowermost portion of the accommodating portion 42 through the inflow path 46, supplied into the filter upstream chamber 42 </ b> A from the opening 46 a, passes through the filter 43, and is filtered. Ink is supplied to the head 2 from the supply port 51 through the outflow path 52 from the uppermost opening 52a of the filter downstream chamber 42B to the downstream chamber 42B.

  At this time, since the stagnation region does not occur over the entire area of the filter 43, the filter 43 can be used effectively.

  Further, the bubbles that have entered the inflow path 46 and the bubbles that have entered the filter upstream chamber 42 </ b> A are lifted by buoyancy and are guided from the bubble discharge path 49 to the top surface 42 b, reach the discharge port 61, and reach the outside of the head tank 4. Discharged. Air bubbles that have entered the filter downstream chamber 42 </ b> B are discharged from the nozzles of the head 2 by supplying pressure to the head tank 4 and suctioning from the nozzles of the head 2.

  Here, since the filter 21 is arranged in the vertical direction (up and down direction), even when the filter area needs to be increased due to the increase in the ink supply amount, the filter 43 and the head tank 4 in the vertical direction. The head unit can be arranged in a space-saving manner because it can be handled only by enlargement.

  Next, a head tank according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is an explanatory side sectional view along the vertical direction of the head tank, and FIG. 5 is an explanatory plan sectional view along the horizontal direction.

  In this embodiment, as shown in FIG. 4, the filter downstream chamber 42B has an inclined surface 42c that is inclined in the vertical direction so that the volume increases from the lower part to the upper part of the accommodating part 42, as shown in FIG. As shown in the drawing, there is an inclined surface 42d that is inclined in a direction in which the volume increases in the horizontal direction from the end portion on the inflow path 46 side of the accommodating portion 42 toward the end portion on the outflow path 52 side.

  That is, the filter downstream chamber 42 </ b> B has inclined surfaces 42 d and 42 c that are inclined in the horizontal direction and the vertical direction, and the position of the opening 52 a that is the uppermost portion of the outflow path 52 that is the ink inflow portion to the supply port 51. Thus, the depth of the filter downstream chamber 42 </ b> B is maximized and is approximately the same as the inner diameter of the supply port 51.

  Thereby, the stagnation of the ink in the filter downstream chamber 42B can be prevented, and the entire area of the filter 43 can be used more efficiently.

  Next, a head tank according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a perspective explanatory view of the head tank, and FIG. 7 is a flat cross-sectional explanatory view along the horizontal direction.

  In the present embodiment, four tank portions 4A to 4D having the same configuration as the head tank 4 according to the second embodiment are formed by the tank case 411 integrated with four colors, and the four accommodating portions 42 are arranged symmetrically. .

  With this configuration, even when multiple types and colors of ink are ejected by one head, the space of the head unit 1 can be saved by arranging the four filters 43 vertically. . Further, when a mold is selected as the method for forming the head tank 4, it is possible to form with a simple mold configuration.

  Here, the case where four types of ink are used is taken as an example, but it is possible to deal with more types of droplet discharge by increasing the accommodating portion 42 in the horizontal direction in FIG.

  Next, a head tank according to a fourth embodiment of the invention will be described with reference to FIGS. FIG. 8 is a front explanatory view of the head tank, and FIG. 9 is a cross-sectional explanatory view along AA in FIG.

  In this embodiment, a part of the top surface 42b of the filter upstream chamber 42A on the discharge port 61 side is an inclined surface 62 that is inclined from the film member 44 side toward the discharge port 61 side.

  With this configuration, the air bubbles can be discharged from the discharge port 61 without staying in the space 63 formed by the film member 44 and the top surface 42b.

  It is also possible to improve the bubble discharge performance by opening the discharge port 61 of the head tank 4 in the same manner as the filter upstream chamber 42A and sealing it with the film member 44 so that there is no part of the top surface 42b. Can do.

  However, in this case, since the outer periphery of the discharge port 61 is formed by the tank case 41 and the film member 44, it is difficult to seal the connection portion between the path connected to the discharge port 61 and the discharge port 61. .

  Therefore, as in the present embodiment, the outer periphery of the discharge port 61 is formed only by the tank case 41 and has a rigid configuration, so that a seal member such as an O-ring can be pressed. It becomes easy to seal the connection portion between the path to be connected and the discharge port 61.

  Next, a head tank according to a fifth embodiment of the invention will be described with reference to FIGS. 10 is a front explanatory view of the head tank, FIG. 11 is a cross-sectional explanatory view taken along the line BB of FIG. 10, and FIG. 12 is an enlarged explanatory view of a main part for explaining an example of a mold when forming a discharge port. is there.

  In the present embodiment, the discharge port 61 is formed to be inclined in a direction from the filter upstream chamber 42A side of the tank case 41 toward the filter downstream chamber 42B side.

  With this configuration, as described above, the outer periphery of the discharge port 61 is formed by the tank case 41, has rigidity, and discharges from the discharge port 61 without causing bubbles to stay in the filter upstream chamber 42A. Can do.

  Further, when the tank case 41 is formed of resin, in the case of the fourth embodiment, an inward slide mold configuration is required for the processing of the undercut portion, and the shape of the accommodating portion 42 and the attachment of the filter 43 are required. There may be restrictions on the attachment position.

  On the other hand, according to the configuration of the present embodiment, as shown in FIG. 12, it can be formed by moving the mold 72 and the mold 73 in the direction of the arrow in FIG. There is no effect on the pasting position.

  Next, an example of the image forming apparatus according to the present invention including the liquid discharge head unit according to the present invention will be described with reference to FIG. FIG. 13 is an overall configuration diagram of the image forming apparatus.

  This image forming apparatus is an image forming unit 102 that is an image forming unit that discharges liquid droplets onto a sheet 100 that is a recording medium, and a conveying unit that conveys the sheet 100. A paper transport unit 103 and a processing liquid application device 104 that applies the processing liquid 401 to the paper 100 on the upstream side in the paper transport direction from the image forming unit 102, and the paper 100 on which an image is formed on the side of the apparatus main body 110 are provided. The paper discharge tray 107 for discharging is provided with a paper feed unit 200 including a paper feed cassette 201 for storing paper 100 under the apparatus main body 110.

  Here, the image forming unit 102 holds a carriage 123 in which the heads of the respective colors are arranged in the main scanning direction with a guide rod 121 and a guide stay (not shown) so as to be movable in the main scanning direction (vertical direction on the paper surface). The scanning motor moves and scans in the main scanning direction via a timing belt spanned between the driving pulley and the driven pulley.

  On this carriage 123, a recording head 124 comprising a liquid ejection head unit according to the present invention for ejecting droplets of each color of black (Bk), cyan (C), magenta (M), and yellow (Y) is mounted. Then, the carriage 123 is moved in the main scanning direction, and droplets are ejected from the recording head 124 while the paper 100 is transported in the paper conveyance direction (sub-scanning direction) orthogonal to the main scanning direction by the paper conveyance unit 103 as a conveyance means. The shuttle type is used for image formation.

  A line-type head in which the heads of the respective colors are arranged in the sub-scanning direction can also be used. Further, the arrangement direction of the heads, the arrangement order of the respective colors, and the nozzle array direction of the heads are not limited to the exemplified configurations.

  As described above, a liquid of a required color is supplied from the main tank 5 that is detachably mounted from the front surface of the apparatus main body 110 to the head tank 4 constituting each recording head 124 on the carriage 123.

  As the head 2 of the recording head 124, a piezoelectric actuator, a thermal actuator, an electrostatic actuator, or the like that uses pressure generating means can be used. However, the droplet discharge means is not limited to these. It is not something.

  The paper transport unit 103 includes an endless transport belt 131 for sucking the paper 100 fed from below and transporting the paper 100 so as to face the image forming unit 102.

  The conveyance belt 131 includes a conveyance roller 132 that is a driving roller, a conveyance roller 133 that secures a plane of the image area with the conveyance roller 132, and a separation roller 134 that is disposed downstream of the conveyance roller 133 in the sheet conveyance direction. It is hung around. The separation roller 134 is a roller that separates the sheet 100 on which the image adsorbed on the conveyance belt 131 is formed by curvature separation.

  Further, in order to charge the surface of the conveyor belt 131, a charging roller 139, which is a charging unit to which a high voltage that is an alternating voltage or a direct current voltage is applied from a high-voltage power supply (AC, DC, or a superimposed bias supply unit of AC and DC). A guide member 140 that guides the conveyance belt 131 in a region facing the image forming unit 102, and a pressing roller (pressure roller) 138 that presses the paper 100 against the conveyance belt 131 at a position facing the conveyance roller 132. Yes.

  The paper feed unit 200 can be inserted / removed from the front side of the apparatus main body 110 and separates and feeds the paper feed cassette 201 for stacking and storing a large number of paper sheets 100 and the paper sheets 100 in the paper feed cassette 201 one by one. A pickup roller 202 and a conveying roller pair 203 are provided.

  Further, on the side of the apparatus main body 110, a straight manual feed tray 105 that manually feeds the paper 100, and a pickup roller 141 and a transport roller pair 142 for feeding the paper 100 one by one from the straight manual feed tray 105 are provided. Yes.

  The processing liquid coating apparatus 104 includes a processing liquid container (not shown) in which a deformable PET film containing the processing liquid 401 is formed in a bag shape, and a pump (not shown) that pumps the processing liquid 401 supplied from the processing liquid container (not shown). And an application unit 410 for applying the treatment liquid 401 to the paper 100 as a recording medium. The processing liquid 401 in the processing liquid container (not shown) is sucked up by a pump (not shown) and supplied to the liquid chamber 402 in the coating unit 410 through a supply path (not shown) to prepare for coating.

  The application unit 410 includes a conveyance roller 434 that conveys the paper 100, an application roller 432 that opposes the conveyance roller 434 and applies the treatment liquid 401 to the paper 100, and supplies the treatment liquid 401 to the application roller 432 to form a liquid film. A squeeze roller 433 for reducing the thickness is provided.

  These rollers are arranged such that the application roller 432 is in contact with the conveyance roller 434 and the squeeze roller 433 is in contact with the application roller 432. Then, a liquid film layer of the processing liquid 401 supplied by the squeeze roller 433 and the application roller 432 is formed, transferred to the transport roller 434 side by the rotation of the application roller 432, and applied to the paper 100.

  Here, the treatment liquid 401 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 401 is applied to the paper 100 without any unevenness in advance, so that the moisture of the ink can quickly permeate the paper 100, the viscosity of the color component is increased, and the drying is also accelerated, thereby fading (feathering). , Bleeding, etc.) and back-through, and a fixing agent (setting agent) that can increase productivity (number of images output per unit time).

  In terms of composition, the treatment liquid 401 is, for example, cellulose that promotes the penetration of moisture into a surfactant (any one of anionic, cationic, nonionic, or a mixture of two or more thereof). And a solution to which a base such as hydroxypropyl cellulose and a talc fine powder are added. Furthermore, fine particles can be contained.

  The sheets 100 stored in the sheet feeding cassette 201 are separated and fed one by one by the pickup roller 202 and sent to the roller pair 205 by the conveying roller pair 204, and processed from the roller pair 205 through the conveying path 300 at a predetermined timing. It is sent to the liquid coating apparatus 104 and the processing liquid 401 is applied by the processing liquid coating apparatus 104.

  Then, the paper 100 coated with the treatment liquid 401 is conveyed to the print conveyance path 305 through the roller pair 145. In the conveyance path 305, the sheet 100 is sucked and held by being fed onto a conveyance belt 131 on which an alternating electric field or a direct current electric field is formed.

  By driving the recording head 124 based on the image signal while moving the carriage 123 with respect to the paper 100 that has been moved to the image formation start position, droplets are ejected onto the paper 100 that has stopped, and one line is left. When recording is completed and recording for one line is completed, the sheet 100 is transported intermittently and the images are sequentially formed on the sheet 100 so that the next line is recorded. Upon receiving a recording end signal or a signal indicating that the trailing edge of the paper 100 has reached the end position of the recording area, the recording operation is completed.

  As a result, the sheet 100 on which the image has been formed is conveyed by the circular movement of the conveying belt 131, separated by curvature by the separation roller 134, and discharged to the sheet discharge tray 107 with the recording surface facing upward by the sheet discharge roller pair 143. Paper.

  As described above, since the image forming apparatus includes the liquid discharge head unit or the head tank (liquid storage tank) according to the present invention, stable image formation can be performed.

  In the present application, the “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, etc., and means a material to which ink droplets or other liquids can be attached. , Recording media, recording paper, recording paper, and the like. In addition, image formation, recording, printing, printing, and printing are all synonymous.

  The “image forming apparatus” means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “Formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply causing a droplet to land on the medium). ) Also means.

  The “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically, for example, includes DNA samples, resists, pattern materials, resins, and the like.

  In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

  Further, the image forming apparatus includes both a serial type image forming apparatus and a line type image forming apparatus, unless otherwise limited.

DESCRIPTION OF SYMBOLS 1 Liquid discharge head unit 2 Head 4 Head tank 5 Main tank 41 Tank case 42 Accommodating part 42A Filter upstream chamber 42B Filter downstream chamber 43 Filter 44 Film member 45 Inflow port 46 Inflow path 51 Supply port 52 Outflow path 61 Ejection port 124 Recording head (Liquid discharge head unit)

Claims (5)

A liquid storage tank for supplying a liquid to be supplied to a head for discharging droplets,
A storage portion for storing the liquid is formed in the tank body,
The container is divided into a filter upstream chamber and a filter downstream chamber by a filter for filtering the liquid,
An inflow port provided in the upper part of the tank body, through which the liquid flows from the outside,
An inflow path for guiding the liquid flowing in from the inflow port to a lower portion of the filter upstream chamber;
A supply port for supplying the liquid to the head provided at a lower portion of the tank body; and an outflow path for guiding the liquid from the upper portion of the filter downstream chamber to the supply port;
The liquid storage tank, wherein an outlet of the inflow path to the filter upstream chamber and an inlet of the filter downstream chamber to the outflow path are arranged at diagonal positions of the storage portion having a substantially rectangular shape.   2. The liquid storage tank according to claim 1, wherein the filter downstream chamber has an inclined surface that is inclined in a vertical direction in a direction in which a volume increases from a lower portion to an upper portion of the storage portion.   2. The filter downstream chamber has an inclined surface that is inclined in a horizontal direction in a direction in which a volume increases from an inflow path side end portion of the housing portion toward an outflow path side end portion. Or the liquid storage tank of 2.   4. A liquid discharge head unit comprising a head for discharging droplets and a liquid storage tank according to claim 1 for storing liquid supplied to the head.   An image forming apparatus comprising the liquid storage tank according to claim 1 or the liquid discharge head unit according to claim 4.

Images