JP2016010898A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress thickening while a device is not used and to reduce wasteful liquid consumption for nozzle restoration when using is restarted.SOLUTION: In a passage 12 which is a flow path for communication with a nozzle 11, a moving body 21 is housed which is made from a magnetic body that can open/close the nozzle 11 and can move along the passage (flow path)12. At a side part of the passage 12, an escaping part 22 where the moving body 21 can escape from the passage 12 is provided. On the side of the escaping part 22, an electromagnet 24 is provided which generates a magnetic force effecting on the moving body 21 in the nozzle 11. While a device is preserved for an extended period, the moving body 21 closes the nozzle 11, and when using is restarted after the long-period of preservation, the moving body 21 is reciprocated in the passage 12.

Description

  The present invention relates to an image forming apparatus.

  As an image forming apparatus, for example, an apparatus using a liquid discharge head for discharging droplets as a recording head, such as an ink jet recording apparatus, is known.

  As a conventional liquid ejection head or image forming apparatus, the elastic body is displaced by magnetic force to eject ink, and the valve body is opened and closed by a driving coil to which a signal current is supplied in the vicinity of the ejection nozzle of the flow path. One having an electromagnetic on-off valve is known (Patent Document 1).

Japanese Patent Laid-Open No. 04-022641

  In an image forming apparatus that uses a liquid discharge head, if the liquid is not used for a long period of time, the liquid in the nozzle of the liquid discharge head thickens and becomes clogged. ) Occurs.

  Therefore, when resuming the use of the device, the liquid is sucked and discharged from the nozzle, or the liquid is pressurized and supplied to the head to forcibly discharge the thickened liquid, thereby recovering the nozzle omission. Yes. Therefore, wasteful liquid consumption increases.

  In this case, by adopting a configuration in which the flow path is opened and closed with a valve body as disclosed in Patent Document 1, it is possible to suppress the thickening of the liquid in the vicinity of the nozzle.

  However, it is difficult to reduce wasteful liquid consumption for performing nozzle recovery when resuming use.

  The present invention has been made in view of the above-described problems, and suppresses the increase in viscosity when the apparatus is not used, and can reduce wasteful liquid consumption for nozzle recovery when the use is resumed. With the goal.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A nozzle for discharging droplets;
A flow path leading to the nozzle;
A magnetic body capable of opening and closing the nozzle and movable in the flow path;
The magnetic body has a retracting portion that can retract from the flow path.

  According to the present invention, it is possible to suppress thickening when the apparatus is not used, and to reduce wasteful liquid consumption for nozzle recovery when resuming use.

FIG. 5 is a schematic cross-sectional explanatory diagram of a main part of an example of a liquid discharge head according to the present invention. It is explanatory drawing with which it uses for shape description of a moving body. It is explanatory drawing with which it uses for description of the state at the time of printing of the liquid discharge head. It is explanatory drawing similarly used for description of the state at the time of long-term storage. FIG. 2 is a schematic explanatory view of a main part of an example of an image forming apparatus including a liquid ejection head according to the present invention. FIG. 3 is an explanatory diagram for explaining a recording head and a cap of a maintenance / recovery mechanism of the image forming apparatus. It is explanatory drawing with which it uses for description of an effect | action by the liquid discharge head and a cap. FIG. 2 is a block diagram for explaining functions of the image forming apparatus. FIG. 6 is a flowchart for explaining an end process when the image forming apparatus is stored for a long time. It is a flowchart with which it uses for description of the use resumption process after a long-term storage similarly.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of a liquid discharge head according to the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional explanatory view of a main part of the head.

  The liquid discharge head includes a nozzle plate 1, a flow path plate 2, a vibration plate 3, a piezoelectric actuator 4 that is a pressure generating unit, and the like.

  The nozzle plate 1 is formed with nozzles 11 for discharging droplets. In the flow path plate 2, an individual liquid chamber (individual flow path) 13 through which the nozzle 11 communicates through the passage 12 is formed. The individual liquid chamber 13 is supplied with liquid from a common liquid chamber 14 formed in a frame member (not shown). The diaphragm 3 forms a wall surface of the individual liquid chamber 13.

  The piezoelectric actuator 4 is bonded to the vibration plate 3, pressurizes the liquid in the individual liquid chamber 13, and discharges droplets from the nozzle 11.

  In this embodiment, a moving body 21 made of a magnetic material that can open and close the nozzle 11 and can move in the passage (flow path) 12 is housed in the passage 12 that is a flow path through which the nozzle 11 communicates. .

  The cross-sectional shape of the moving body 21 can be, for example, a circular cross-section as shown in FIG. 2A, or an elliptical cross-section as shown in FIG.

  In addition, a coating film such as a resin can be formed on the surface of the moving body 21. Thereby, liquid resistance can be improved. In addition, nozzle clogging can be reduced by using a member that easily scrapes and removes the liquid fixed in the flow path.

  In addition, a retreating portion 22 in which the moving body 21 can retreat from the passage 12 is provided on the side portion of the passage 12.

  Further, an electromagnet 24 that is a magnetic force generating means for generating a magnetic force that reaches the moving body 21 in the nozzle 11 is provided on the side of the retracting portion 22.

  Next, the operation of the liquid discharge head will be described with reference to FIGS. FIG. 3 is an explanatory diagram for explaining the state during printing, and FIG. 4 is an explanatory diagram for explaining the state during long-term storage.

  First, when performing printing, as shown in FIG. 3, the electromagnet 24 is turned on to generate a magnetic force that attracts at least the moving body 21 in the nozzle 11 as shown in FIG. It is moved and retracted in the area 22.

  Thereby, since the nozzle 11 is opened, the piezoelectric actuator 4 can be driven and a droplet can be discharged from the nozzle 11.

  On the other hand, when long-term storage is performed in which the apparatus is stopped for a long time when the apparatus is turned off, the moving body 21 is turned off by turning off the electromagnet 24 as shown in FIG. Moves to the nozzle 11 side by its own weight, and the moving body 21 closes the nozzle 11.

  Thereby, it can suppress that liquid, such as the ink in the nozzle 11, contacts external air and a viscosity rises (thickening).

  When the use is resumed after long-term storage, the moving body 21 is reciprocated in the passage 12 by the weight of the moving body 21 and the generation of magnetic force by the electromagnet 24.

  Accordingly, the liquid in the flow path such as the nozzle 11, the passage 12, and the individual liquid chamber 13 is agitated, and the liquid in the vicinity of the nozzle 11 flows to reduce the viscosity, so that the viscosity can be made uniform.

  In this way, it is possible to suppress thickening when the apparatus is not used and reduce wasteful liquid consumption for nozzle recovery when resuming use.

  Next, an example of an image forming apparatus including the liquid ejection head according to the present invention will be described with reference to FIG. FIG. 5 is a schematic explanatory diagram of a main part of the image forming apparatus.

  This image forming apparatus is a line type image forming apparatus, and a recording head unit 101 as image forming means for forming an image by ejecting liquid droplets onto a sheet 100 as a recording medium, and the recording head unit 101 as a recording sheet. A conveying belt 102 that conveys the paper 100, a paper feed tray 103 that stores the paper 100, and a paper discharge tray 104 that discharges the paper 100 on which an image is formed.

  The recording head unit 101 includes a line-type liquid ejection head 111 having a plurality of nozzle rows in which a plurality of nozzles that eject droplets are arranged in a length corresponding to the paper width. Here, the liquid ejection head 111 includes nozzle rows that eject ink droplets of colors of yellow (Y), magenta (M), cyan (C), and black (K). Note that the recording head can be mounted on the carriage as a serial type image forming apparatus. The line type head may have a configuration in which a plurality of heads are arranged in a staggered manner.

  The conveyor belt 102 is an endless belt, and is configured to circulate between the conveyor roller 121 and the tension roller 122. The paper 100 can be held on the transport belt 102 by, for example, a configuration that performs electrostatic suction, suction by air suction, or other known transport means.

  The sheets 100 stored in the sheet feed tray 103 are separated one by one by the pickup roller 131 and are conveyed by the conveying roller pair 132 through the conveying path 133. Then, it is sent out from the pair of transport rollers 134 to the transport path 135 at a predetermined timing, and is sent onto the transport belt 102 through the rollers 136 and held.

  With this configuration, each color droplet is ejected from the recording head unit 101 to form an image on the paper 100 that is fed onto the conveyance belt 102 and conveyed by the circumferential movement of the conveyance belt 102. Thereafter, the paper 100 is discharged to the paper discharge tray 104.

  Next, the recording head of the image forming apparatus and the cap of the maintenance / recovery mechanism will be described with reference to FIG. FIG. 6 is an explanatory diagram for explaining the same.

  In the liquid ejection head 111, similarly to the liquid ejection head described above, a moving body 21 made of a magnetic material is accommodated in a passage 12 through which each nozzle 11 of each nozzle row communicates, and a retracting portion 22 is provided on the side of the passage 12. In addition, an electromagnet 24 that generates a magnetic force is disposed on the moving body 21.

  On the other hand, a cap 140 for capping the nozzle surface of the liquid discharge head 111 is provided.

  The cap 140 is provided with an annular coil 141 which is a magnetic field generating means. By energizing (feeding) the annular coil 141, a magnetic field that reaches the moving body 21 of the liquid ejection head 111 can be generated. Although a magnetic field is generated here, a magnetic material can be arranged in the cap 140 to generate a magnetic force.

  By providing the annular coil 141 on the cap 140 that moves forward and backward with respect to the liquid ejection head 111, the annular coil 141 that is a magnetic field generating means can be disposed near the nozzle of the liquid ejection head 111 when capping is performed. In addition, magnetic field generating means such as an annular coil can be separately arranged in the vicinity of the nozzle.

  The operation of the liquid discharge head and the cap thus configured will be described with reference to FIG. FIG. 7 is an explanatory diagram for explaining the operation.

  First, when performing printing, the electromagnet 24 is turned on to generate a magnetic force that attracts the moving body 21, and the moving body 21 is moved and retracted into the retracting portion 22.

  As a result, as shown in FIG. 6, the nozzle 11 is opened, and droplets can be discharged. In FIG. 6, the cap 140 is illustrated in a state of facing the liquid discharge head 111, but when performing printing, the cap 140 is moved to a position retracted from between the liquid discharge head 111 and the paper 100.

  When long-term storage is designated when the power is turned off, the liquid ejection head 111 is capped with a cap 140 as shown in FIG. Then, the electromagnet 24 is turned off so that the moving body 21 can move. On the other hand, by supplying power to the annular coil 141, a magnetic field that attracts the moving body 21 in the direction of the white arrow 142 is generated, and the moving body 21 is moved to the nozzle 11 side.

  Thereby, since the moving body 21 closes the nozzle 11, it can suppress that liquids, such as an ink in the nozzle 11, contact with external air and a viscosity rises (thickening).

  When the use is resumed after long-term storage, the moving body 21 is reciprocated in the passage 12 while switching between the generation of magnetic force by the electromagnet 24 and the generation of magnetic field by the annular coil 141.

  Thereby, the liquid of the flow path in the vicinity of the inside of the nozzle 11 can be agitated and flowed to reduce the viscosity, and the viscosity can be made uniform.

  Next, functions of the image forming apparatus will be described with reference to the block diagram of FIG.

  The image forming unit 201 includes the above-described recording head unit 101 and first control unit 301 according to the present invention that controls power supply (generation of magnetic force) to the electromagnet 24 of the liquid ejection head 111 of the recording head unit 101. .

  The conveyance unit 202 includes the conveyance belt 102 and the like. The sheet feeding unit 203 includes a sheet feeding tray 103 and a pickup roller 131.

  The maintenance supply unit 205 includes a supply mechanism 206 that supplies liquid to the liquid discharge head 111 of the recording head unit 101 of the image forming unit 201. In addition, the maintenance supply unit 205 includes a capping mechanism 207 including a cap 140 for capping the nozzle surface of the liquid ejection head 111 and a suction unit connected to the cap 140.

  Further, the maintenance supply unit 205 includes a second control unit 302 according to the present invention that controls power feeding (generation of magnetic field or generation of magnetic force) to the annular coil 141 that is a magnetic field generation unit provided in the cap 140.

  In addition, a long-term storage discriminating unit 303 and a storage unit 304 that stores information related to long-term storage are provided.

  The long-term storage discriminating means 303 discriminates whether or not long-term storage for stopping the apparatus in a state where it is not used for a long time is designated by the information 310 from the user when the power is turned off. Stores this in the storage means 304.

  Further, the long-term storage determination unit 303 stores in the storage unit 304 whether or not long-term storage has been designated when the power is turned off when the apparatus is started (when the power is turned on). Retrieve information and determine.

  In other words, in this embodiment, the user designates the long-term storage, so that the long-term storage is stored in the storage device 304 regardless of the actual stop period of the device, and the storage is performed by the long-term storage determination unit 303 when the use is resumed. It is determined from the storage information of the device 304 whether or not it was long-term storage.

  Further, a viscosity determining unit 305 is provided for determining whether or not the liquid viscosity of the recording head unit is equal to or higher than a predetermined viscosity (threshold).

  Next, end processing when the image forming apparatus is stored for a long time will be described with reference to the flowchart of FIG.

  First, when the power switch is turned off, the power-off process is started. Then, through a printer driver or the like, the user is requested to input information on whether or not to store the apparatus for a long period of time. The determination result is stored in the storage unit 304.

If long-term storage is not designated, a normal capping operation is performed by the capping mechanism 207, and the power OFF end processing is completed. Note that, when the power-off process is completed, the actual apparatus is turned off.

  On the other hand, when long-term storage is designated, the first control means 301 stops the generation of the magnetic force by the electromagnet 24, moves the moving body 21 into the nozzle 11, and closes the nozzle 11 with the moving body 21.

  Thereafter, a capping operation is performed by the capping mechanism 207 to complete the power OFF end process.

  Next, use resumption processing after long-term storage will be described with reference to the flowchart of FIG.

  First, when the power switch is turned on, the power on process is started. Then, it is determined by reading the information stored in the storage unit 304 whether long-term storage has been designated when the storage unit 304 was last turned off.

  Here, when long-term storage is not designated when the power is turned off last time, a normal activation sequence is performed to make the print ready state.

  On the other hand, when long-term storage was specified when the power was turned off last time, the viscosity discrimination means 305 detects the viscosity of the ink in the flow path, and whether or not the detected viscosity is equal to or higher than the threshold value. Is determined.

  When the detected viscosity is equal to or higher than the threshold value, the first control unit 301 controls the generation of the magnetic force by the electromagnet 24, and the second control unit 302 controls the generation of the magnetic field by the annular coil 141. 21 is reciprocated in the passage 12 to stir the ink in the flow path.

  After that, when the viscosity is not equal to or higher than the threshold value, the moving body 21 is moved and retracted to the retracting unit 22 as it is, and a normal start-up sequence is performed to make it ready for printing.

  Here, the moving body 21 is reciprocated by controlling the magnetic force generation and magnetic field generation by the electromagnet 24 and the annular coil 141 by the first control means 301 and the second control means 302, but as described above, the annular coil In the configuration without 141, the moving body 21 is moved by controlling the generation of the magnetic force by the electromagnet, and stirring is performed.

  Further, in the liquid discharge head, a through hole having an opening diameter smaller than the opening diameter of the nozzle is formed in the magnetic body, and the through hole communicates with the nozzle so that the droplet is discharged from the liquid ejected by the nozzle. It can also be set as the structure which can discharge a small drop.

  In the present application, image formation, recording, printing, printing, and printing are all synonymous. The “image forming apparatus” means an apparatus that forms an image by discharging a liquid onto a medium. In addition, “image formation” not only applies an image having a meaning such as a character or a figure to a medium but also applies an image having no meaning such as a pattern to the medium (simply applying a droplet to the medium). It also means to land on. The term “ink” is not limited to what is called an ink unless specifically limited, and is used as a general term for all liquids that can perform image formation. For example, DNA samples, resists, pattern materials, resins and the like are also included.

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

  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 Nozzle plate 2 Flow path plate 3 Vibration plate 4 Piezoelectric actuator 11 Nozzle 12 Passage 13 Individual liquid chamber 21 Moving body (magnetic body)
22 evacuation part 24 electromagnet (magnetic force generating means)
111 Liquid discharge head 140 Cap 141 Ring coil (magnetic field generating means)
301 First Control Unit 302 Second Control Unit 303 Long-term Storage Determination Unit 304 Storage Unit 305 Viscosity Determination Unit

Claims (8)

A nozzle for discharging droplets;
A flow path leading to the nozzle;
A magnetic body capable of opening and closing the nozzle and movable in the flow path;
A liquid discharge head, wherein the magnetic body includes a retracting portion that can retract from the flow path. The liquid discharge head according to claim 1, further comprising magnetic force generation means for generating a magnetic force that reaches the magnetic body. The liquid discharge head according to claim 1, wherein the magnetic body has a circular or elliptical cross-sectional shape. The liquid discharge head according to claim 1, wherein a coating film is formed on a surface of the magnetic body. A liquid discharge head according to any one of claims 2 to 4,
An image forming apparatus comprising: a first control unit that controls generation of a magnetic force by the magnetic force generation unit of the liquid discharge head. Long-term storage determining means for determining whether or not long-term storage for stopping the device for a long period of time when the device is turned off is specified;
Storage means for storing the determination result of the long-term storage determination means;
Viscosity discriminating means for discriminating whether or not the viscosity of the liquid in the flow path of the liquid discharge head is equal to or higher than a threshold,
When the apparatus is turned on, it is stored in the storage means that the long-term storage is designated, and when the viscosity is equal to or higher than a predetermined threshold, the first control means is controlled by the magnetic force generation means. The image forming apparatus according to claim 5, wherein the magnetic body is moved in the flow path by controlling generation of a magnetic force. Magnetic field generating means that can be arranged in the vicinity of the nozzle of the liquid discharge head and generates a magnetic field or a magnetic force that reaches the magnetic body of the liquid discharge head;
The image forming apparatus according to claim 5, further comprising: a second control unit that controls generation of a magnetic field or a magnetic force by the magnetic field generation unit. Long-term storage determining means for determining whether or not long-term storage for stopping the device for a long period of time when the device is turned off is specified;
Storage means for storing the determination result of the long-term storage determination means;
Viscosity discriminating means for discriminating whether or not the viscosity of the liquid in the flow path of the liquid discharge head is equal to or higher than a threshold,
When the apparatus is turned on, it is stored in the storage means that the long-term storage is designated, and when the viscosity is equal to or greater than a threshold value, the first control means generates the magnetic force by the magnetic force generation means. The image forming apparatus according to claim 7, wherein the second control unit controls the generation of a magnetic field or a magnetic force by the magnetic field generation unit to move the magnetic body in the flow path. .

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