JP4760412B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus. More specifically, the present invention relates to an ink jet recording apparatus having a capping unit that sucks ink from an ejection port of an ink jet print head (hereinafter also referred to as an ink jet head).

  In an inkjet recording device, if the ink is not used for a long period of time, the viscosity of the ink increases due to the evaporation of water from the ink discharge port of the print head, or clogging occurs, or paper dust enters the nozzle that is the discharge port and clogs. This causes troubles such as the occurrence of bubbles and the occurrence of bubbles from the nozzles, resulting in a pressure loss in the internal pressure and the inability to eject ink. Furthermore, if unnecessary ink adheres to the ejection port surface, it may cause ink ejection bending or ejection failure.

  When printing is performed in such a state, the output image deteriorates, such as missing or dark portions in the output image. For this reason, the maintenance for recovering the state of clogging or pressure loss is necessary.

  As this maintenance method, a method is disclosed in which the discharge port surface is covered and covered with a cap, and the discharge port surface and the cap that are in a close contact state are partially separated to perform suction, thereby recovering non-discharge (for example, patents). Reference 1).

Further, a partial cap unit that covers only a part of the plurality of discharge ports, a suction unit that sucks ink from the partial discharge port through the cap unit, or one of the plurality of discharge ports. And a pressure means for discharging ink from ejection ports other than some of the blocked ejection ports (for example, Patent Document 2).
Japanese Patent No. 3083409 Japanese Patent No. 2718724

  In recent years, the number of nozzles that eject ink has been increasing in inkjet recording apparatuses due to the improvement in printing speed. When non-ejection occurs in these nozzles, the output image is degraded.

  As a recovery means, in the method of performing suction with a cap as in Patent Document 1 and recovering non-ejection, if the number of nozzles is large, it is necessary to cover the entire print head in order to recover one nozzle. A large amount of ink is discharged to recover one nozzle, and ink is wasted.

  In addition, since the print head is miniaturized, the nozzle portion has a high density, and it is difficult to manufacture a cap corresponding to a single nozzle, which increases costs. Therefore, in actuality, suction is performed in a form including several nozzles in the vicinity, instead of sucking a single nozzle. With respect to these problems, Patent Document 2 devises a cap that covers a part of the discharge port. However, in the configuration described in Patent Document 2, due to the structure of the cap, in the recovery operation in the sequence of abutting, sucking, holding, and separating the cap, the remaining ink in the portion where the cap and the print head are in contact with the nozzle If it adheres to the edge, it will cause the ink to bend out.

  The present invention has been made in view of the above situation, and in a means for recovering a nozzle where non-ejection has occurred, by sucking the nozzle pinpoint, it is possible to recover the non-ejecting nozzle with a small amount of waste liquid, It is an object of the present invention to provide an ink jet recording apparatus that can reduce the bending of ink emission due to the ink remaining due to the contact between the print head and the cap portion adhering to the edge of the nozzle.

The above object is achieved by the following configuration.
1. In an ink jet recording apparatus comprising: a print head having a plurality of discharge ports for discharging ink; and a capping unit that covers the discharge ports of the print head and collects ink discharged from the discharge ports. An open-cell type porous elastic member having a hollow structure capable of contacting a discharge port surface provided with a discharge port of the print head and opening the discharge port of the print head; and the porous elastic member. An ink jet recording apparatus comprising: a base member to be stored; and a suction unit that communicates with a hollow structure portion of the porous elastic member and sucks ink from an ejection port of the print head.
2. 2. The ink jet recording apparatus according to claim 1, further comprising an urging unit supported by the base member for urging the porous elastic member with respect to a discharge port surface of the print head.
3. 3. The ink jet recording apparatus according to claim 1, wherein the porous elastic member covers the vicinity around one discharge port.
4). In Lee inkjet recording apparatus according to any one of item 1 to item 3, to support the base member, and a moving means for moving the capping means, by said moving means, said printing said porous elastic member In contact with the discharge port surface of the head, by the moving means, the porous elastic member is urged and compressed on the discharge port surface, and the porous elastic member is compressed by the suction unit, An ink jet recording apparatus comprising: control means for sucking ink from an ejection port of the print head.
5. In Lee inkjet recording apparatus according to any one of item 1 to item 3, to support the base member, and a moving means for moving the capping means, by said moving means abuts against compressed the discharge port surface While releasing the compression of the porous elastic member and keeping the porous elastic member in contact with the discharge port surface, the suction means sucks ink and the moving means sucks ink. An ink jet recording apparatus comprising: control means for separating the porous elastic member from the discharge port surface.
6). In Lee inkjet recording apparatus according to any one of item 1 to item 3, to support the base member, and a moving means for moving the capping means, by said moving means, said printing said porous elastic member In contact with the discharge port surface of the head, by the moving means, the porous elastic member is urged and compressed on the discharge port surface, and the porous elastic member is compressed by the suction unit, The porous elastic member while releasing the compression of the porous elastic member abutted and compressed on the surface of the discharge port by the first control unit for sucking ink from the discharge port of the print head and the moving unit In the state where the ink is in contact with the discharge port surface, the suction unit sucks ink, and the moving unit sucks the ink and the porous elastic member is separated from the discharge port surface. And after the control by the first control means , the suction is stopped for a predetermined time while maintaining the compressed state of the porous elastic member, and then the control by the second control means is performed. An ink jet recording apparatus.

  According to the above configuration, ink can be sucked from the ejection port by contacting the porous elastic member having a hollow structure formed of an open-cell type sponge so that the hollow structure portion releases the ejection port. .

  According to the above configuration, the porous elastic member is closely contacted and compressed so that the hollow portion releases the discharge port, thereby preventing suction from the porous elastic member around the hollow portion, and suction force from the discharge port. Can concentrate on the suction.

  According to the above configuration, the porous elastic member covers only the predetermined discharge port and the vicinity thereof in which the non-discharge occurs among the plurality of discharge ports, and sucks ink from the predetermined discharge port and the vicinity thereof, Suction from the discharge port that does not require suction can be prevented, and the amount of waste liquid can be reduced.

  According to the above configuration, the suction force can be concentrated on the suction from the discharge port, the non-discharge nozzle can be sucked by simple control, and the nozzle can be recovered.

  According to the above configuration, the ink is sucked by the suction means while the porous elastic member is released from compression and the porous elastic member is in contact with the discharge port surface, and the moving means The porous elastic member is separated from the discharge port surface while sucking ink, so that the ink adhering to the discharge port surface is absorbed by the porous elastic member and the ink absorbed by the porous elastic member is removed. It can be discharged from the porous elastic member by the suction means, and a decrease in the absorption power of the porous elastic member can be prevented.

  According to the above configuration, the inkjet can recover the non-ejection nozzle by simple control and remove the ink adhering to the ejection port surface in a short time in a continuous operation, and perform an efficient non-ejection nozzle recovery operation. A recording apparatus can be provided.

  Embodiments relating to a recovery device and an ink jet recording apparatus of the present invention will be described below with reference to the drawings.

  FIG. 1 is a conceptual diagram of an ink jet recording apparatus A according to the present invention. The ink jet recording apparatus of the present invention is not limited to the following form.

  The print head H is mounted on the carriage 30. The carriage 30 reciprocates along the main scanning direction, and the print head H reciprocates along the main scanning direction, and image recording is performed by ejecting ink in the process. 11 is closely contacted and separated.

  Ink is supplied to the print head H from the ink cartridges A 1 and A 2 through the ink supply path 20. In this embodiment, in addition to the ink cartridge A1, an ink cartridge A2 having a lower density ink than the ink cartridge A1 is provided in order to express the gradation of the image more precisely.

  Between the ink cartridges A1 and A2 and the print head H, a supply valve A3 and an intermediate tank A4 are disposed from the upstream side.

  The supply valve A3 is a valve configured to be electrically opened and closed, such as an electromagnetic valve, and adjusts the amount of ink supplied from the ink cartridges A1 and A2 to the intermediate tank A4.

  The intermediate tank A4 temporarily stores the ink supplied from the ink cartridges A1 and A2 to the print head H. Replace the ink cartridge when the remaining ink level is low. Further, the intermediate tank is disposed below the print head H, so that a negative pressure is generated by keeping the height low, and an appropriate pressure for ink ejection is maintained.

  The capping means 1 moves the cap part 11, the rack and pinion 12 that moves the cap part up and down and abuts and separates the cap part on the discharge port surface, and moves the cap part and the rack and pinion in the nozzle part movement direction. It comprises a cap part moving means (not shown), a suction pipe 13 as a suction means, a suction pump 14 and a waste liquid tank 15 for discharging the waste liquid sucked by the suction pump 14.

  As shown in FIG. 2, the capping means 1 moves the cap portion in the nozzle row direction of the print head by a cap portion moving means (not shown), and the print head scans in the carriage direction in the direction perpendicular to the nozzle row, that is, in the main scanning direction. And control the portion requiring suction to an appropriate position. When the portion requiring suction is in an appropriate position, the cap portion 11 is moved up and down by the rack and pinion 12, whereby the cap portion and the discharge port surface are brought into contact with and separated from each other, thereby performing a suction recovery operation.

  Next, the configuration of the capping unit according to the present invention will be described.

  FIG. 3 is a configuration diagram of a cap portion according to the present invention. The cap part 11 is formed of an open-cell type sponge and has a porous elastic member 110 having a hollow part 110a, a hollow structure support 112 that supports the porous elastic member 110, a spring 113 that is a biasing means, The porous elastic member includes a base body having a shape that covers a part and a bottom surface of the porous elastic member, a spring, and a support.

  The porous elastic member communicates with the hollow portion of the support and is connected to the suction pipe 13.

  The open-cell type sponge that forms the porous elastic member is not limited, but for example, a polyurethane material such as a ruby cell of Toyo Polymer Co., Ltd., a PVA (polyvinyl alcohol) sponge, or the like can be used.

  A functional configuration of the ink jet recording apparatus according to the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a functional configuration of the inkjet recording apparatus A according to the present invention. The same constituent elements as those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

  The control means 18 measures an MPU 18A composed of a microprocessor for executing various control procedures, a ROM 18B for storing control procedures and data, a RAM 18C for temporarily storing various data, a capping timer 18D having a timer function, and a waiting time. It comprises a waiting timer 18H and the like.

  Further, the control means 18 has an interface 18F that receives image data transferred from the host computer HC of the host computer, and an interface 18G that sends control signals to the print head driver 183 that drives the print head H.

  The carriage motor driver 182, the ejection drive means (print head driver) 183, the carry motor driver 184 and the capping motor driver 185, according to various control signals from the control means 18, respectively, have the carriage motor 3, print head H, carry motor 11 and The capping motor 121 is driven.

  Further, the detection signals of the home position sensor 22, the capping sensor 142, and the discharge detection sensor 152 are taken into the control means 18 through the interface 18G.

  Reference numeral 23 denotes a main power switch, which is a switch for supplying external power (AC 100 V in the present embodiment) to the ink jet recording apparatus A so as to be in an operating state.

  Reference numeral 24 denotes a sub power switch. When the main power switch 23 is turned on, the operator repeatedly presses the sub power switch 24, so that the sub power control means 25 provided in the control means 18 outputs the sub power supply 30. Is configured to repeat ON and OFF.

  Reference numeral 30 denotes a sub power supply device that receives power from an external power source via the main power switch 23, is turned on / off by a control signal from the sub power control means 25, and is directly supplied with power from the main power supply device 29. The capping means excluding the (member) and other controlled means, that is, the carriage motor driver 182, the transport motor driver 184, the capping motor driver 185, the home position sensor 22, and the cap part 11 with respect to the discharge port surface Then, power is supplied to a capping motor 121 for making contact and separation, or a display means such as a liquid crystal panel for displaying print data, abnormality data, and the like.

  In the configuration described above, when the main power switch 23 is turned on, power is supplied from the external power source to the main power supply device 29 and the sub power supply device 30, and the ink jet recording apparatus A enters a print standby state.

  In this state, when image data from the host computer HC is captured by the control means 18 through the interface 18F, the captured image data is subjected to image processing and then converted into a control signal according to a control procedure stored on the ROM 18B. The converted control signal executes various operations such as driving the print head driver 182 via the interface 18G and performing a printing operation.

  The operation of the ink jet recording apparatus according to the present invention will be described.

  FIG. 8 is a conceptual diagram illustrating an example of a discharge detection sensor that detects a non-discharge nozzle.

  The ejection detection sensor 152 includes a light emitting element 152A and a light receiving element 152B arranged at both ends of the ink ejection unit in the nozzle row direction. The light emitting element and the light receiving element are arranged in the same straight line along the nozzle row direction, and the light emitted from the light emitting element is received by the light receiving element.

  If the ink is normally ejected from the ejection port, the light emitted from the light emitting element is temporarily blocked by the ink and received by the light receiving element. Therefore, the ejection detection sensor detects that the ejection port ejects normal ink. Detect if you do. On the other hand, if the ink is not ejected from the ejection port, the light emitted from the light emitting element is received as it is without being blocked by the light receiving element, so that the ejection detection sensor detects that the ejection port does not eject ink.

FIG. 5 is a flowchart showing a recovery operation sequence performed in the ink jet recording apparatus. FIG. 6 is a diagram illustrating a relationship between the state of the cap portion and the position of the discharge port surface in each process.
(Operation sequence)
Step S1. The cap portion 11 aligned with the position of the non-ejection nozzle is moved upward by the rack and pinion 12, and the porous elastic member of the cap portion and the ejection port surface come into contact with each other to cover the non-ejection nozzle N (FIG. 6B). .
Step S2. The abutted cap part is further moved upward to compress the porous elastic member (FIG. 6C).
Step S3. After compressing the porous elastic member in step S2, a suction operation is performed to make the hollow portion have a negative pressure. Since the density of the porous elastic member itself is increased by the compression of the porous elastic member in step S2, the hollow portion can maintain an appropriate suction pressure (negative pressure) even when the suction pump is operated.
Step S4. After the suction operation is stopped, the state of the cap portion is maintained, and the negative pressure inside the porous elastic member is brought to a state near atmospheric pressure by ink coming from the nozzle.
Step S5. The cap portion is lowered by the rack and pinion, and the compression of the porous elastic member is released in a state where the porous elastic member is in contact with the discharge port by the spring (FIG. 6D).
Step S6. 5. above. In this state, empty suction is performed to suck ink in the hollow portion and ink absorbed by the porous elastic member.
Step S7. In a state where the idle suction is continued, the discharge port surface and the porous elastic member of the cap portion are separated at a predetermined speed or less (FIG. 6E). The predetermined speed is a speed at which the ink droplets on the ejection port surface can be absorbed by the porous elastic member without breaking in the middle.

  In this embodiment, the print head of the shuttle type ink jet recording apparatus is used, but the present invention can also be applied to a line head, a multi head, and the like of the line type ink jet recording apparatus.

  FIG. 7 is a schematic diagram when the recovery device according to the present invention is applied to a line head of a line-type ink jet recording apparatus and a multi-head in which a plurality of heads are arranged in a line. Both the line head type and the multi-head type cap unit can be moved in the paper transport direction and the nozzle row direction by a moving means (not shown), and the cap unit moves to the non-ejection nozzle position and performs a recovery operation. When the recovery device according to the present invention is applied to the line type and multi type heads, the amount of waste liquid is reduced and the effect is greater.

  As described above, the cap portion, the suction means, and the recovery operation sequence according to the present invention can reduce the amount of waste liquid in the recovery of the non-discharge nozzle, and the contact between the discharge port surface and the porous elastic member of the cap portion. This makes it possible to achieve a recovery method that can reduce the bending of ink ejection due to the remaining ink remaining on the edge of the nozzle.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

With the ink jet recording apparatus shown in FIG. 1, the cap portion, suction means, and recovery operation sequence of the present invention were evaluated for non-ejection nozzles. In the evaluation, actual printing was performed, and the presence or absence of missing portions or dark portions in the output image was visually evaluated.
<Evaluation conditions>
1. Porous elastic member: Polyurethane continuous porous elastic body (Ruby cell manufactured by Toyo Polymer Co., Ltd.)
Pore diameter 5 to 7 μm, porosity 80%, density 0.22 g / cm ³
2. Suction pressure during suction: 30 kPa
3. 3. Time for compressing and sucking the porous elastic member: about 5 seconds 4. Holding time of the porous elastic member when suction is stopped: approximately 7 seconds Empty suction time: about 20 seconds Separation speed between discharge port surface and porous elastic member: 0.4 mm / second Under the above conditions, the recovery operation of the non-discharge nozzle was performed 20 times. Actual printing was performed for each recovery operation, and the presence or absence of missing output images or dark portions was visually evaluated, but no occurrence was observed. Recovery operation for non-ejecting nozzles and removal of ink remaining on the ejection port surface Was good.

1 is a conceptual diagram of an ink jet recording apparatus according to the present invention. It is a schematic diagram of capping means. It is a block diagram of the cap part which concerns on this invention. It is a control block diagram of the ink jet recording apparatus according to the present invention. It is a flowchart showing the sequence of recovery operation | movement. FIGS. 6A to 6E are views showing the relationship between the state of the cap portion and the ejection surface position in each process of the recovery operation. It is a schematic diagram when the recovery device according to the present invention is applied to a line type ink jet recording apparatus. It is a conceptual diagram which shows an example of a discharge detection sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capping means 11 Cap part 110 Porous elastic member 110a Hollow part 111 Base body 112 Support body 113 Spring 12 Rack and pinion 13 Suction pipe 14 Suction pump 15 Waste liquid tank 20 Ink supply path 30 Carriage 40 Moisturizing cap 152 Discharge detection sensor A1, A2 Ink cartridge A3 Supply valve A4 Intermediate tank H Print head

Claims (6)

In an ink jet recording apparatus comprising: a print head having a plurality of discharge ports for discharging ink; and a capping unit that covers the discharge ports of the print head and collects the ink discharged from the discharge ports.
The capping means can be in contact with a discharge port surface provided with a discharge port of the print head, and has a hollow structure that opens the discharge port of the print head. An ink jet recording apparatus comprising: a base member that houses a porous elastic member; and a suction unit that communicates with a hollow structure portion of the porous elastic member and sucks ink from an ejection port of the print head. The inkjet recording apparatus according to claim 1, further comprising an urging unit supported by the base member for urging the porous elastic member against an ejection port surface of the print head. The ink jet recording apparatus according to claim 1, wherein the porous elastic member covers a vicinity around a single ejection port. In Lee inkjet recording apparatus according to any one of 請 Motomeko 1 to 3,
Moving means for supporting the base member and moving the capping means;
By the moving means, the porous elastic member is brought into contact with the discharge port surface of the print head,
By the moving means, the porous elastic member is urged and compressed on the discharge port surface,
An ink jet recording apparatus comprising: a control unit that sucks ink from an ejection port of the print head by the suction unit in a state where the porous elastic member is compressed. In Lee inkjet recording apparatus according to any one of 請 Motomeko 1 to 3,
Moving means for supporting the base member and moving the capping means;
While the compression of the porous elastic member abutted and compressed on the discharge port surface is released by the moving unit and the porous elastic member is in contact with the discharge port surface, Suck
An ink jet recording apparatus comprising: control means for separating the porous elastic member from the discharge port surface while sucking ink by the moving means. In Lee inkjet recording apparatus according to any one of 請 Motomeko 1 to 3,
Moving means for supporting the base member and moving the capping means;
By the moving means, the porous elastic member is brought into contact with the discharge port surface of the print head,
By the moving means, the porous elastic member is urged and compressed on the discharge port surface,
In a state where the porous elastic member is compressed, the suction means sucks ink from the discharge port of the print head by the suction means; and
While the compression of the porous elastic member abutted and compressed on the discharge port surface is released by the moving unit and the porous elastic member is in contact with the discharge port surface, And second control means for separating the porous elastic member from the discharge port surface while sucking ink by the moving means ,
After the control by the first control means , the suction is stopped for a predetermined time while maintaining the compressed state of the porous elastic member, and then the control by the second control means is performed.

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