JP2008036833A - Ink filling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable sure performance of the opening and closing action of a solenoid valve even in a state that a negative pressure is acted to a printing head by capping the head. <P>SOLUTION: The solenoid valve 50 is opened in a state without the negative pressure acted to the printing head H while an ink tank 32b is pressurized, whereby a predetermined amount of ink is supplied to an ink passage. After the solenoid valve 50 is closed, the ink in the ink passage is ejected by acting the negative pressure to the printing head H. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink filling method.

  2. Description of the Related Art Conventionally, an ink jet printer as an image forming apparatus has been known as means for recording characters and images (hereinafter collectively referred to simply as “images”). In this ink jet printer, printing is performed by reciprocating a print head that pressurizes ink supplied from an ink tank and ejects ink droplets in the width direction of the paper.

  An ink jet printer capable of performing a large amount of printing by such a method has a main ink tank having a large capacity for each color and a flexibility having a variable volume connected to each ink tank by a pipe. And a small-capacity sub-tank for each color formed in a bag shape made of a material and having airtightness.

A method of initially filling ink into the sub tank of the ink jet printer having such a configuration will be described. First, the solenoid valve disposed between the sub tank and the ink tank is closed, the print head is capped and sucked, and the air in the sub tank is discharged. Next, the electromagnetic valve is opened, and the ink in the ink tank is supplied to the sub tank and filled (see, for example, Patent Documents 1 and 2).
JP 2003-211689 A Japanese Patent Laid-Open No. 2003-21690

  However, in the ink filling method described above, there is a possibility that the solenoid valve cannot be opened in a state where the negative pressure is applied by capping the print head. This is a significant problem when rubber packing is used to close the ink flow path between the solenoid valve and the ink tank, and the rubber packing is dry and negative pressure is acting. Then, the rubber packing is in a state of being fixed to the inner wall of the ink flow path, the ink flow path cannot be opened, and there is a risk that ink filling will be poor.

  The present invention has been made in view of the above points, and an object of the present invention is to reliably perform the opening / closing operation of the solenoid valve even in a state where a negative pressure is applied by capping the print head. Is to be able to.

  In order to achieve the above object, in the ink filling method of the image forming apparatus according to the present invention, the rubber packing of the solenoid valve is wetted with ink before the print head is capped and sucked to prevent the rubber packing from sticking. I tried to do it.

That is, the invention of claim 1 includes an ink tank in which ink is stored, a sub-tank that is disposed above the ink tank and temporarily stores ink supplied under pressure from the ink tank, and the sub-tank. An ink filling method for an image forming apparatus, comprising: a print head for discharging supplied ink; and an opening / closing means for opening and closing an ink flow path between the ink tank and the sub tank.
Supplying a predetermined amount of ink to the ink flow path by opening the opening and closing means in a state where no pressure is applied to the print head while pressurizing the ink tank;
A closing step of closing the opening and closing means after the supplying step;
And a discharging step of discharging the ink in the ink flow path by applying a negative pressure to the print head after the blocking step.

  Therefore, according to the present invention, after the ink tank is pressurized, the opening / closing means is opened in a state where no negative pressure is applied to the print head, a predetermined amount of ink is supplied to the ink flow path, the opening / closing means is closed, and then the print head is A negative pressure is applied to the ink to discharge the ink in the ink flow path. Thereby, the state between the rubber packing used for the opening / closing means and the inner wall of the ink flow path can be made wet. As a result, even when a negative pressure is applied to the print head, the problem that the rubber packing is dry, that is, the problem that the rubber packing is fixed to the inner wall of the ink flow path is solved. The ink channel can be smoothly opened and closed by the opening and closing means, and an advantageous effect can be obtained in suppressing ink filling failure.

  According to a second aspect of the present invention, after the discharging step, the ink tank is pressurized, and the open / close means is opened in a state where a negative pressure is applied to the print head to fill the ink flow path with ink. The filling step is performed.

  Therefore, according to the present invention, ink can be reliably filled into the ink flow path between the ink tank and the sub tank.

  According to a third aspect of the present invention, after the first filling step, a negative pressure is applied to the print head in a state where the opening / closing means is opened, and the sub tank is interposed between the sub tank and the print head. And a second filling step of filling the print head with ink.

  Therefore, according to the present invention, it is possible to reliably carry out ink filling between the sub-tank and the print head and the print head.

  According to a fourth aspect of the present invention, each of the steps is performed using a cleaning liquid tank in which a cleaning liquid is stored instead of the ink tank in which the ink is stored.

  Therefore, according to the present invention, each process is performed using a cleaning liquid tank in which cleaning liquid is stored instead of the ink tank. Therefore, the present invention can be applied not only at the time of initial ink filling but also at the time of replacing the ink tank of a printer that has not been operated for a long time. That is, when a printer that has not been used for a long time is restarted, cleaning with a cleaning liquid may be performed in order to eliminate ink clogging due to residual ink remaining in the ink flow path or the like. At this time, the rubber packing used for the opening / closing means is fixed to the inner wall of the ink flow path by the dried residual ink, and there is a possibility that the opening / closing means cannot be opened in a state where negative pressure is applied. Therefore, if the opening / closing means is opened without applying a negative pressure and a predetermined amount of cleaning liquid is supplied to the ink flow path so that the rubber packing is wetted with the cleaning liquid, the ink flow path is smoothly opened and closed by the opening / closing means. be able to.

  As described above, according to the ink filling method of the present invention, the opening / closing means is opened without applying a negative pressure to the print head, the ink tank is pressurized, and a predetermined amount of ink is supplied to the ink flow path. After the means is closed, a negative pressure is applied to the print head to discharge the ink in the ink flow path. Thereby, the state between the rubber packing used for the opening / closing means and the inner wall of the ink flow path can be made wet. As a result, even when the negative pressure is applied to the print head, the problem that the rubber packing is dry, that is, the problem that the rubber packing adheres to the inner wall of the ink flow path is solved. The ink flow path can be smoothly opened and closed by the opening and closing means, and an advantageous effect can be obtained in suppressing ink filling defects and the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

<Embodiment>
FIG. 1 is a perspective view showing a partially omitted configuration of an ink jet printer A as an image forming apparatus according to an embodiment of the present invention. This printer A is used in a photographic print system. For example, image data transmitted via a communication cable is received from a reception block that performs image data acquisition and order information acquisition and performs necessary correction processing. The printing is performed on the paper P (recording medium) based on the order information.

-Overall configuration-
2 is a plan view showing the configuration of the printer A partially omitted, FIG. 3 is a rear view, FIG. 4 is a right side view, FIG. 5 is a front view, and FIG. 6 is a side sectional view showing a schematic configuration of the printer A. is there. As shown in FIGS. 1 to 6, the printer A has a paper storage unit 1 provided at the lower part of the apparatus for storing a roll-shaped paper P, and a paper P drawn from the paper storage unit 1. In order to store the printing unit 2 provided on the upper part of the apparatus so as to perform recording printing of image data and ink supplied to the printing unit 2 disposed on the side of the apparatus (on the left and right sides in FIG. 3). Ink cartridge mounting portions 3 and 3.

  In the upper part of the printer A, on the downstream side in the transport direction of the printing unit 2, a roller cutter unit 4 for cutting the printed paper P into a predetermined print size, and a serial number on the back surface of the paper P. A back surface printing unit 5 for printing, a decurling unit 6 for removing and curling the paper P wound in a roll shape, and a discharge tray 7 for receiving the discharged paper P are provided. Although only shown in FIG. 6, the printer A is covered with a main body cover 8 except for the discharge tray 7.

  The paper storage unit 1 is positioned almost directly below the print unit 2 and stores the long paper P wound in a roll shape while being held by a core roller as shown in FIG. It is configured. Here, the paper storage unit 1 forms a part of a main body cover 8 that covers the entire printer A and is covered with a door member 12 that can be opened and closed. By opening the door member 12, the paper P can be replaced.

  In addition, in this embodiment, although the kind of paper P accommodated in the said paper accommodating part 1 is only one kind, it is not limited to this form, It comprises so that two or more types of paper P can be accommodated. It doesn't matter.

  The print unit 2 includes a print head H that forms an image by ejecting ink onto the paper P, and a paper holding unit D that is provided below the print head H and holds the paper P at a printing position by suction. (See FIGS. 2 and 6 for details).

  The print head H is configured to be movable along a guide rail 15 extending in the main scanning direction. Specifically, the rotational force of the drive motor 16 is transmitted to the drive belt 17 via the pulley, and the printer head H moves in the main scanning direction according to the rotation amount of the drive belt 17.

  Further, the print head H has two head units 38 and 38 (see FIG. 6) arranged in the sub-scanning direction, and ink is ejected from nozzles provided in these head units 38 and 38. A predetermined image, characters, and the like can be printed on the paper P.

  Each of the ink cartridge mounting portions 3 and 3 includes box-like cases 31 and 31 disposed on the left and right sides of the printer A, and inks having different hues are enclosed in the cases 31 and 31. .. Are accommodated detachably (in FIG. 3, three cartridges are accommodated on the left side and four cartridges are accommodated on the right side). Therefore, by removing these ink cartridges 32, 32,... From the case, the used or used ones can be replaced with new ones.

  These ink cartridges 32, 32,... Are respectively yellow (Y), magenta (M), cyan (C), black (K), red (R), violet (V), and clear (CL: (Transparent) ink is enclosed.

  Further, the ink supplied from the ink cartridges 32, 32,... Is temporarily placed at a height position between the ink cartridge mounting unit 3 and the printing unit 2 on the left side when viewed from the discharge side of the printer A. Sub-tanks 52, 52,... For storing are provided. These sub tanks 52, 52,... Are connected to the print head H of the print unit 2, and ink in the sub tanks 52, 52,... Is discharged by negative pressure when ink is ejected from the nozzles of the print head H. Is supplied to the print head H.

-Ink supply system-
Next, the ink supply system of the printer A will be described. As shown in FIG. 8, when the ink cartridge 32 is mounted at the mounting position of the ink cartridge mounting portion 3, one end of the ink supply conduit 51 is connected to the outlet 32 c of the ink cartridge 32. The ink supply pipe 51 is provided with an electromagnetic valve 50 (opening / closing means), and the other end of the ink supply pipe 51 is connected to the sub tank 52. Then, the ink in the ink tank 32 b of the ink cartridge 32 is supplied to the sub tank 52 through the electromagnetic valve 50 and the ink supply pipe 51, and the ink in the sub tank 52 is sent out to the print head H through the flexible pipe 53. It is configured as follows.

  From the ink cartridge 32 to the sub tank 52, ink is sent out by pressurized air supplied to the ink cartridge 32 by an air pressurizing unit 56 described later, while from the sub tank 52 to the print head H, the print head H When ink is ejected from the ink ejection nozzle of each head unit 38, the ink flows due to the negative pressure generated in the pressure chamber by the piezo element. The sub tank 52 is attached to the print head H at a predetermined height so that ink is supplied to the print head H at an appropriate pressure.

  By configuring the ink supply system as described above, the ink in the ink cartridge 32 is once stored in the sub tank 52 and supplied from the sub tank 52 to the print head H. Therefore, the sub tank 52 serves as a pressure damper. As a result, the pressure fluctuation generated in the ink cartridge 32 can be prevented from being directly transmitted to the print head H, and excessive pressure acts on the print head H to cause ink leakage and the like. Can be prevented. In FIG. 8, only one ink supply system is shown, but in reality, seven ink supply systems are formed corresponding to seven types of inks having different hues. However, there is only one air pressurizing unit 56 and pressure regulating valve 57 described below.

  An air supply path 55 is connected to the introduction port 32d of the ink cartridge 32 mounted at the mounting position of the ink cartridge mounting portion 3. The air supply path 55 is connected to an air pressurization unit 56 including a pressurization pump that operates in response to a control signal from the controller 100, and ink is supplied from the air pressurization unit 56 through the air supply path 55. Pressurized air is supplied into the case member 32 a of the cartridge 32. The air supply path 55 is provided with a pressure regulating valve 57 (pressure reducing valve) that receives a control signal from the controller 100 and adjusts the air pressure supplied into the case member 32a. By the air pressurizing unit 56 and the pressure regulating valve 57, the inside of the case member 32a is brought to a predetermined pressure, whereby ink is led from the ink tank 32b to the ink supply line 51 and supplied to the sub tank 52. Thus, the air pressurization unit 56 and the pressure regulating valve 57 constitute an ink cartridge pressurizing unit that applies pressure to the ink cartridge 32 to lead out the ink of the ink cartridge 32 to the ink supply conduit 51.

  The ink cartridge mounting portion 3 has U-shaped cases 31 and 31 (see FIGS. 2, 4, and 6), and the cases 31 and 31 are fixed to a base 75. Thus, the base 75 is formed in a cylindrical shape.

  The side opposite to the opening of the cylindrical portion (front side of the casing) is closed by a cartridge receiving member 33 (see FIG. 4) extending in the vertical direction, while the opening side (rear side of the casing) is opened. Yes. Accordingly, the cases 31 and 31 and the base 75 correspond to the peripheral wall portion of the recess, and the cartridge receiving member 33 corresponds to the bottom wall portion of the recess (the back wall portion facing the opening).

  As shown in FIG. 8, the ink cartridge 32 has a substantially rectangular box-shaped resin case member 32a which is hermetically sealed, and is disposed in the case member 32a. And a bag-like ink tank 32b. A cartridge receiving member 33 is provided at one end in the longitudinal direction of the case member 32a.

  FIG. 9 is a perspective view showing the configuration of the cartridge receiving member 33, and FIG. 10 is a side sectional view showing the configuration of the cartridge receiving member 33. As shown in FIGS. 9 and 10, the cartridge receiving member 33 is connected to the main body 34 extending in the vertical direction, the electromagnetic valve 50 attached to the main body 34, and the ink tank 32 b, and in the ink tank 32 b. An outlet 32c for leading ink out of the case member 32a and an inlet 32d for introducing pressurized air into the case member 32a are provided.

  The electromagnetic valve 50 receives the control signal from the controller 100 and controls the opening / closing operation of the outlet 32c. Specifically, the solenoid valve 50 receives a control signal and drives the cylinder rod 35a so as to freely advance and retract, the cam unit 36 connected to the cylinder rod 35a of the cylinder 35, and the cylinder rod 35a interlocking with the advance / retreat operation. And an opening / closing unit 37 for opening / closing the outlet 32c via the cam unit 36.

  A sliding shaft 35b protruding in a direction perpendicular to the axial direction of the cylinder rod 35a is attached to the tip of the cylinder rod 35a of the cylinder 35. The sliding shaft 35b is slidably fitted in a long sliding hole 36d of a cam member 36a constituting a cam unit 36 described later.

  The cam unit 36 is attached to a cam member 36a having an L-shaped cross section and one of the two sides forming the L-shape of the cam member 36a, and one end of the opening / closing shaft 37b of the opening / closing unit 37 is engaged / disengaged. An engagement member 36b that is freely held, and a rotation shaft 36c that passes through the intersection of the cam member 36a and the engagement member 36b and that can rotate about the cam member 36a and the engagement member 36b are provided. .

  A long sliding hole 36d is formed at the tip of the other side of the two sides forming the L shape of the cam member 36a, and the sliding shaft 35b of the cylinder 35 is slidably fitted. Yes.

  The opening / closing unit 37 is formed in a bottomed cylindrical shape, and is fixed with a bottomed cylindrical opening abutting against the main body portion 34 of the cartridge receiving member 33, and a cylindrical bottom of the case member 37a. An opening / closing shaft 37b slidably fitted in a through-hole penetrating the shaft, a rubber packing 37c attached to one end of the opening / closing shaft 37b and opening or closing the outlet 32c by elastic deformation, and an opening / closing shaft 37b And a compression spring 37e disposed between the cylinder bottom of the case member 37a and the flange 37d and urging the rubber packing 37c in the direction of closing the outlet 32c. ing.

  The case member 37a is formed with a flange at the opening side periphery of the bottomed cylindrical shape, and is fixed to the main body portion 34 by screwing in a state where the flange is in contact with the main body portion 34.

  The open / close shaft 37b has a rubber packing 37c attached to one end thereof, and the other end thereof is detachably held by an engaging member 36b of the cam unit 36. The opening / closing shaft 37b slides in the axial direction via the cam unit 36 in conjunction with the forward / backward movement of the cylinder rod 35a of the cylinder 35, whereby the outlet 32c is opened or closed.

  The opening / closing operation of the electromagnetic valve 50 configured as described above will be described with reference to FIGS. FIG. 11 is a side sectional view showing a state in which the outlet is opened, and FIG. 12 is a side sectional view showing a state in which the outlet is closed.

  As shown in FIG. 11, when the outlet 32c is opened, the cylinder rod 35a is contracted and accommodated in the cylinder 35. At this time, the sliding shaft 35b at the tip of the cylinder rod 35a slides in the sliding hole 36d of the cam member 36a of the cam unit 36, so that the cam member 36a and the engaging member 36b are centered on the rotating shaft 36c. Rotates counterclockwise. The opening / closing shaft 37b of the opening / closing unit 37 engaged with the engaging member 36b is held in a state of protruding outward (to the left in FIG. 11) of the case member 37a against the urging force of the compression spring 37e. The

  As a result, the rubber packing 37c attached to one end of the opening / closing shaft 37b is elastically deformed and held at a position away from the inner wall of the main body 34 around the outlet 32c, and the outlet 32c is opened. The In FIG. 11, the arrows indicate the flow of ink.

  On the other hand, as shown in FIG. 12, when the outlet 32 c is closed, the cylinder rod 35 a extends and protrudes from the cylinder 35. At this time, the sliding shaft 35b at the tip of the cylinder rod 35a slides in the sliding hole 36d of the cam member 36a of the cam unit 36, so that the cam member 36a and the engaging member 36b are centered on the rotating shaft 36c. Rotate clockwise. As a result, the opening / closing shaft 37b of the opening / closing unit 37 engaged with the engaging member 36b is released from the inside of the case member 37a by the urging force of the compression spring 37e by releasing the engagement of the engaging member 36b. It slides toward (right side in FIG. 11) and is pressed and held. As a result, the rubber packing 37c attached to one end of the opening / closing shaft 37b is elastically deformed and the outlet 32c is closed.

  By configuring the ink supply system as described above, the ink in the ink cartridge 32 is temporarily stored in the sub tank 52 and supplied from the sub tank 52 to the print head H, so that printing is not interrupted. The ink cartridge 32 can be replaced. In addition, since the sub tank 52 also serves as a pressure damper, it is possible to prevent the pressure fluctuation generated in the ink cartridge 32 from being directly transmitted to the print head H, and an excessive pressure is applied to the print head H. Can prevent ink leakage and the like from occurring. In FIG. 8, only one ink supply system is shown, but in reality, seven ink supply systems are formed corresponding to seven types of inks having different hues.

  The ink cartridge 32 is configured by storing an ink tank 32b formed in a bag shape using a flexible material in a resin case. The ink cartridge 32 further includes an air pressurizing unit 56 that supplies pressurized air to the inside of the case via an air supply path 55, and a pressure adjusting valve 57 that adjusts the air pressure supplied to the inside of the case. ing. In such a configuration, by setting the inside of the case to a predetermined pressure, a predetermined amount of ink can be supplied from the ink tank 32 b into the ink supply pipe 51.

  The sub tank 52 is formed in a bag shape using a flexible material such as a resin sheet, and is configured to repeatedly expand and contract in the thickness direction depending on the amount of ink filled therein. Specifically, the sub tank 52 is formed in a cylindrical shape by welding the upper and lower sides of two resin sheets, for example, and then has a substantially central portion in the cylinder axis direction so as to divide the internal space into two. What is obtained by welding and welding to a sheet in a state where resin sealing members 52a and 52a in which two supply pipes 52c and 52d are integrally formed in openings at both ends in the cylinder axial direction are positioned Thus, two tank chambers 52 b and 52 b are formed in one sub tank 52. As a result, the two tank chambers 52b can temporarily store inks having different hues.

  The sub tank 52 is erected in a storage portion 54 (see FIGS. 4, 5, and 8) provided on the left side of the casing of the printer A (in FIG. 8, one sub tank 52 is arranged). Is schematically shown), in the vicinity of the sub tank 52 (in the present embodiment, above the side surface of the sub tank 52) is disposed in the storage portion 54, and the two tank chambers 52b of the sub tank 52 are arranged. Two sub-tank sensors S are provided for outputting detection signals to the controller 100 in accordance with the amount of expansion in each thickness direction.

  Here, in the storage portion 54, the subtank 52 extends in the vertical direction at a position corresponding to the belly portions (the portion that expands most in the thickness direction) of the two tank chambers 52 b on one surface of the subtank 52. Two plate members 54 a configured to be able to swing in the thickness direction of 52 are disposed. A supply pipe 52c provided in a wall portion facing each other in the longitudinal direction of the storage portion 54 (the longitudinal direction of the casing) is provided to communicate with each tank chamber 52b of the sub tank 52 in a state where the sub tank 52 is stored. , 52d are cut out so as to avoid them.

  The sub tank sensor S is disposed so as to contact the upper portion of the plate member 54a. When the side surface of the sub tank 52 is displaced in the thickness direction as the tank chamber 52b expands or contracts, the sub tank sensor S responds to the displacement. The tilt of the plate member 54a is detected.

  Specifically, when the remaining amount of ink in the tank chamber 52b of the sub tank 52 becomes a predetermined amount (for example, 9 ml) or less, the tank sensor S is not in contact with the plate member 54a and hardly tilted. The controller 100 is configured to operate the electromagnetic valve 50 to be in an open state and supply ink into the tank chamber 52b of the sub tank 52 so that the remaining amount of ink becomes an appropriate amount (for example, 10 ml). On the other hand, when an appropriate amount of ink is filled in the tank chamber 52b of the sub tank 52, the tank sensor S tilts in contact with the plate member 54a. Is closed to stop the supply of ink to the tank chamber 52b of the sub tank 52.

  The ink cartridge mounting unit 3 is provided with a detachable sensor 58 that determines whether or not the ink cartridge 32 is present in the ink cartridge mounting unit 3.

-Ink initial filling procedure-
Next, a procedure for filling ink from the ink tank 32b to the print head H during the initial operation of the inkjet printer A will be described.

  First, as shown in FIG. 11, pressurized air is supplied to the inside of the case by the air pressurizing unit 56, and the inside of the case is brought to a predetermined pressure to pressurize the ink tank 32b.

  Next, the solenoid valve 50 is operated in a state where no negative pressure is applied to the print head H, and the outlet 32c is opened. Specifically, the cylinder rod 35a of the cylinder 35 is extended, and the sliding shaft 35b at the tip is slid in the sliding hole 36d, so that the cam member 36a and the engaging member 36b of the cam unit 36 are connected to the rotating shaft 36c. Rotate counterclockwise as center. Accordingly, the opening / closing shaft 37b is pulled outward (left side in FIG. 11) against the urging force of the compression spring 37e in conjunction with the engaging member 36b, and the rubber packing 37c attached to one end of the opening / closing shaft 37b. Is elastically deformed to form a gap between the rubber packing 37c and the inner wall of the main body 34 around the outlet 32c, and the outlet 32c is opened. As a result, a predetermined amount of ink is supplied to the ink supply conduit 51 between the ink tank 32 b and the sub tank 52.

  After supplying a predetermined amount of ink, the electromagnetic valve 50 is operated to close the outlet 32c. Specifically, as shown in FIG. 12, the cylinder rod 35a of the cylinder 35 is contracted and accommodated in the cylinder 35, and the slide shaft 35b at the tip of the rod is slid in the slide hole 36d, thereby forming a cam. The cam member 36a and the engaging member 36b of the unit 36 are rotated clockwise around the rotation shaft 36c. As a result, the engagement state of the engagement member 36b and the opening / closing shaft 37b is released, the opening / closing shaft 37b is pressed inward (right side in FIG. 12) by the urging force of the compression spring 37e, and the one end of the opening / closing shaft 37b is pressed. The attached rubber packing 37c is elastically deformed and comes into close contact with the inner wall of the main body 34 around the outlet 32c, so that the outlet 32c is closed.

  In this way, the problem due to the rubber packing 32c being dried, that is, the problem that the rubber packing 32c is fixed to the inner wall of the main body 34 around the outlet 32c is solved. The outlet 32c can be opened and closed smoothly.

  Next, a negative pressure is applied to the print head H, and the ink and air in the ink supply pipe 51 are discharged to a cap portion (not shown). Thereby, the preparatory process for ink filling is completed.

  Next, after pressurizing the ink tank 32b, the solenoid valve 50 is operated in a state where a negative pressure is applied to the print head H, the outlet 32c is opened, and ink is supplied from the ink tank 32b to the sub tank 52. The pipe 51 is filled with ink. Then, the ink is further filled, and finally, the flexible pipe 53 between the sub tank 52 and the print head H and the print head H are filled with the ink via the sub tank 52. Thereby, the initial ink filling is completed.

  As described above, according to the ink filling method according to the present embodiment, the ink tank 32 b is pressurized, while the electromagnetic valve 50 is opened in a state where no negative pressure is applied to the print head H, and ink is supplied to the ink supply line 51. After a predetermined amount is supplied and the electromagnetic valve 50 is closed, a negative pressure is applied to the print head H to discharge the ink in the ink supply pipe 51. Thereby, the space between the rubber packing 37c used in the electromagnetic valve 50 and the inner wall of the main body 34 around the outlet 32c can be made wet. As a result, even when a negative pressure is applied to the print head H, a problem caused by the rubber packing 37c being dried, that is, the rubber packing 37c is fixed to the inner wall of the main body 34 around the outlet 32c. Since the problem is solved, the outlet 32c can be smoothly opened and closed by the electromagnetic valve 50, and an advantageous effect can be obtained in suppressing ink filling failure.

  In this embodiment, in order to supply ink into the ink supply pipe 51, the electromagnetic valve 50 is operated after pressurizing the ink tank 32b. However, the present invention is not limited to this embodiment. Alternatively, after the solenoid valve 50 is actuated to open the outlet 32c, the ink tank 32b may be pressurized to supply ink.

  In the present embodiment, the method for surely opening and closing the solenoid valve 50 at the time of initial ink filling by performing each step using the ink tank 32b in which ink is stored has been described. For example, the present invention can be applied to the replacement of the ink tank 32b of the printer A that has not been operated for a long time.

  That is, when the printer A that has not been used for a long time is restarted, cleaning with a cleaning liquid may be performed in order to eliminate ink clogging due to residual ink remaining in the ink supply pipe 51 and the like. At this time, the rubber packing 37c constituting the electromagnetic valve 50 is fixed to the inner wall of the main body 34 around the outlet 32c by the dried residual ink, and may not be opened in a state where negative pressure is applied. . Therefore, if the electromagnetic valve 50 is opened without applying a negative pressure and a predetermined amount of cleaning liquid is supplied to the ink supply pipe 51 so that the periphery of the rubber packing 37c is wetted with the cleaning liquid, the outlet port 32c is driven by the electromagnetic valve 50. Can be opened and closed smoothly.

-Paper transport mechanism-
As shown in FIG. 6, the printer A is provided with a paper storage portion 1 for storing a long paper P wound in a roll shape at the lower part of the printer A, while the paper P is pulled out from the paper storage portion 1 to be predetermined. A transport mechanism accommodating portion 10 is provided in the upper part of the apparatus. The transport mechanism accommodating portion 10 accommodates a paper transport mechanism that performs various processes such as image printing and cutting while transporting along the transport path. Here, the paper storage section 1 and the transport mechanism storage section 10 are partitioned from each other by a partition wall 11, and an opening for transporting paper P is formed in a part of the partition wall 11.

  In the present embodiment, in addition to supplying the paper P from the paper storage unit 1, a manual feed unit configured to supply paper of a predetermined size from the manual feed tray 81 is also provided. A case where the paper P is supplied from the paper storage unit 1 will be described.

  The paper storage unit 1 stores a long paper P wound in a roll shape, and the direction of the paper P is changed by pulling the leading end of the paper P from the roll and winding it on the guide roller 41. Then, the paper is sandwiched between a conveyance driving roller 43 that forms a paper conveyance mechanism through the opening of the partition wall 11 and a pair of pressure-bonding rollers 44, 44 arranged to face the conveyance driving roller 43.

  The paper P conveyed by the rotation of the conveyance driving roller 43 is supplied to the printing unit 2 on the downstream side in the conveyance direction, and an image is printed on the paper P by the print head H.

  Then, the printed paper P is sent to the roller cutter unit 4 by the post-printing conveyance roller 45 and cut into a predetermined print size. The cut paper P is sent to the back surface printing unit 5 by the transport roller 46 after cutting, and a reference number and the like are printed on the back surface of the paper P, and then sent to the decurling unit 6 by the transport roller 47.

  In the decurling unit 6, in order to remove the curl of the paper P wound in a roll shape, the decurling is performed in a state where the paper P is bent in a direction opposite to the curling direction of the paper P by the decurling roller 48, The decurled paper P is discharged to the discharge tray 7 by the discharge roller 49. In the following description, the transport upstream side and the downstream side when the paper P is transported during the printing are also simply referred to as the upstream side and the downstream side, respectively.

  Hereinafter, each component of the printer A will be described in detail. In addition to the paper P wound in the form of a roll, the paper storage unit 1 is wound with the paper P, and the guide roller 41 that changes the tip of the paper P toward the opening side of the partition wall 11; and the paper storage unit 1 In order to maintain the airtightness, a closing roller 42 that closes the opening of the partition wall 11 and a humidifier 60 that adjusts the humidity in the paper storage unit 1 are disposed.

  The humidifier 60 adjusts humidity by supplying moisture into the paper storage unit 1 and prevents the paper storage unit 1 from drying and cracking the surface of the paper P.

  The closing roller 42 prevents moisture supplied into the paper storage unit 1 by the humidifier 60 from diffusing from the opening of the partition wall 11 to the transport mechanism storage unit 10 side, and prevents moisture from the outside. It prevents intrusion and keeps the humidity in the paper storage unit 1 constant, and has a role as a sealing member for ensuring airtightness in the paper storage unit 1. Note that it is preferable that at least the outer peripheral surface of the closing roller 42 be made of, for example, a sponge material because the hermeticity with the opening can be improved. Further, a sponge material capable of absorbing moisture is provided in the waste liquid tank 65 so that the moisture contained in the waste ink is absorbed.

  The conveyance drive roller 43 is rotated in the forward direction in which the paper P is pulled out of the paper storage unit 1 and conveyed to the printing unit 2 side by an electric motor (not shown), and in the reverse direction to return the paper P into the paper storage unit 1. The rotation can be switched. Thereby, after the printed part of the paper P is cut into a predetermined size by the roller cutter unit 4 on the downstream side in the transport direction from the transport driving roller 43, the long paper P is returned to the upstream side and the top of the paper P The long paper P can be returned into the paper storage unit 1 when printing is performed from the beginning or when the paper P is supplied from the manual feed unit instead of the long paper P.

  As shown in FIGS. 1 and 2, the print unit 2 includes a guide rail 15 that guides the print head H in a main scanning direction X (a direction perpendicular to the conveyance direction (sub-scanning direction Y) of the print paper P); Printing can be performed by the print head H, which is wound around two pulleys and drives the print head H to reciprocate along the guide rail 15, the drive motor 16 which rotates the pulley, and the print head H. A paper holding part D that sucks and holds at a possible position, and a pressure-bonding post-printing transport roller 45 disposed on the downstream side of the paper holding part D are provided. Here, the main scanning direction X corresponds to the width direction of the print paper P, and the sub-scanning direction Y corresponds to the longitudinal direction of the print paper P.

  As shown in FIG. 6, the print head H has head units 38, 38,... Provided with a large number of ink discharge nozzles on the bottom surface (the surface facing the paper holding portion D) in two stages in the sub-scanning direction. (The head unit 38 does not have to be two stages, and may be one stage or three stages or more).

  Each of the head units 38 has the same configuration, and each of the head units 38 is composed of seven nozzle arrays arranged in the main scanning direction X and ejecting the inks of the respective colors. In each nozzle array, ink discharge nozzles are arranged in a row in the sub-scanning direction Y. Accordingly, each head unit 38 is configured to be able to form a color image by itself. The print head H is scanned in the main scanning direction X for each step of paper conveyance. At this time, at each position in the main scanning direction X, each head unit 38 ejects ink from a predetermined ink ejection nozzle of each color. Discharge at the same time. Here, the ink discharge nozzle in the present embodiment is of a general piezo type that discharges ink by changing the volume of the pressure chamber filled with ink by a piezo element.

  In addition, a standby position for the print head H to wait when printing is not being performed is set at a position outside the print area in the main scanning direction X of the printer head H. A cap portion (not shown) configured to suck ink from the nozzles of the print head H is provided to prevent thickening.

  Although not particularly illustrated, the cap portion has a space with a negative pressure inside, and a small amount of ink is sucked into the space from the nozzles of the print head H. Thereby, it is possible to prevent the ink from being thickened by the nozzle and becoming difficult to discharge. Here, the space of the cap portion is designed to have a negative pressure inside by using a pump as an air pressurizing unit 56 of an ink supply system described later.

  Although not shown, the cap portion communicates with the waste liquid tank 65, and a discharge pump for discharging ink is interposed between the cap portion and the waste liquid tank 65. The discharge pump is configured to be driven by a motor that drives a pressure pump of an ink supply system described later. That is, a plurality of pumps are driven by one motor.

  As shown in FIGS. 2 and 6, the paper holding part D has a plurality of suction holes 21a, 21a,... That open on the surface (upper surface) corresponding to the print area of the print head H and is flushed. A guide plate 21 having a flushing hole 21b corresponding to the area, a first compartment 22 provided below the print area of the print head H in the guide plate 21 and communicating with the suction hole 21a, and a print head in the guide plate 21 A negative pressure is exerted on the surface of the guide plate 21 through the suction holes 21a by sucking and exhausting the air in the second compartment 23 provided below the H flushing region and communicating with the flushing hole 21b, and the first compartment 22 And a fan 24 as suction means for sucking and holding the paper P on the surface of the guide plate 21; 2 compartments 22, 23 exhaust pipe 25 for communicating the and a (see FIG. 7).

  The flushing hole 21b is for receiving a small amount of ink ejected from the nozzles of the print head H at the start of printing in order to prevent the ink from thickening. The waste ink ejected to the flushing hole 21b is discarded. It is stored in the waste liquid tank 65 through the pipe 26 (see FIG. 7).

  The guide plate 21 is further formed with a plurality of substantially rectangular border holes 21c at intervals in the paper width direction of the paper P. Specifically, the edge hole 21c is formed at a position corresponding to the paper width of a predetermined paper size (for example, A4, B5, etc.) and the paper width of the paper P when the paper P is placed on the guide plate 21. It is formed at a position where a part of the edge hole 21c is exposed from the edge in the direction.

  In this way, even when a part of the ink ejected from the print head H to the edge in the paper width direction of the paper P protrudes from the paper P when performing borderless printing on the paper P, the paper P protrudes. The ink is discharged from the edge hole 21c, and it is possible to prevent the ink protruding from the paper edge from adhering to the surface of the guide plate 21 and soiling the plate surface.

  7 is a cross-sectional view taken along the line II in FIG. As shown in FIG. 7, below the guide plate 21, a first compartment 22 is provided below the print area of the print head H and communicates with the suction holes 21 a, and below the flushing area of the print head H on the guide plate 21. A second compartment 23 that is provided and communicates with the flushing hole 21b is provided.

  A fan 24 is attached to the lower part of the first compartment 22. By driving the fan 24, the air in the first compartment 22 is sucked and exhausted through the exhaust hole 22a. As a result, a negative pressure is generated on the surface of the guide plate 21, and the paper P is removed from the guide plate 21. Adsorbed and held on the surface.

  In the second compartment 23, a sponge-like ink absorbing material 23a capable of absorbing ink is disposed, and the ink soaked into the ink absorbing material 23a is accumulated in the second compartment 23. It has become. The second compartment 23 communicates with the first compartment 22 through the exhaust pipe 25. Specifically, one end of the exhaust pipe 25 is connected to the bottom surface of the first compartment 22, and the other end is connected to the side wall of the second compartment 23. In this way, by connecting the other end of the exhaust pipe 25 to the side wall of the second compartment 23, the waste ink accumulated at the bottom of the second compartment 23 is moved toward the first compartment 22 by the suction force of the fan 24. I try not to be inhaled.

  The exhaust pipe 25 constitutes a damping means for attenuating the suction force of the fan 24. Specifically, the air volume inside the exhaust pipe 25 is set by appropriately setting the inner diameter of the exhaust pipe 25 to about 1 to 10 mm. The resistance increases, and the suction force for sucking and exhausting the ink mist through the flushing hole 21b is attenuated.

  Further, a waste pipe 26 is connected to the bottom surface of the second compartment 23 for collecting the flushed waste ink and ink mist collected in the second compartment 23 and guiding them to the waste liquid tank 65.

  As described above, the suction force of the fan 24 that sucks and holds the paper P is attenuated through the exhaust pipe 25 and used for sucking and exhausting the ink mist, whereby a dedicated exhaust fan is used to suck and exhaust the ink mist. There is no need to provide a single fan, and the number of parts can be reduced by reducing the size of the apparatus body. Further, it is advantageous in reducing power consumption.

  Further, the suction force for sucking and exhausting the ink mist is weaker than the suction force for sucking and holding the paper P, and the air flow around the print head H is disturbed to suck the ejected ink necessary for image formation. There is no risk of adversely affecting image formation.

  Further, the ink mist can be sucked and exhausted with a desired suction force simply by setting the inner diameter of the exhaust pipe 25 to about 1 to 10 mm, for example, and the amount of attenuation of the suction force of the fan 24 can be reduced with a simple configuration. Can be set.

  The roller cutter unit 4 has a circle blade, and is configured to cut the paper P into a predetermined size by moving the circle blade in the paper width direction while rotating the circle blade. A post-cutting conveyance roller 46 for feeding the cut paper P is disposed on the downstream side of the roller cutter unit 4. Then, the paper P is transported to the back surface printing unit 5 on the downstream side by the rotation of the post-cutting transport roller 46.

  Further, below the roller cutter unit 4, a cutter waste collection box 70 for collecting chips of the paper P after cutting is disposed. The cutter waste collection box 70 is configured to be slidable along the paper P discharge direction (right direction in FIG. 6) and detachable from the apparatus main body, so that the user can easily discard the cutter waste. .

  A handle 71 is attached to the back side (right side in FIG. 6) of the cutter waste collection box 70. And the back side of the cutter waste collection box 70 is formed with a transparent plastic material, and the accommodation state of chips can be visually confirmed.

  In order to reliably collect the cut pieces of the paper P after cutting, for example, the cutter waste collection box 70 and the first compartment 22 of the paper holding unit D are communicated with each other through an exhaust pipe (not shown), and the fan 24 Therefore, a configuration may be adopted in which the pressure below the roller cutter unit 4 is set to a negative pressure via the exhaust pipe so that the chips are reliably collected in the cutter waste collection box 70.

  The back surface printing unit 5 prints a serial number or the like on the back surface of the paper P, and is disposed on the back surface side of the paper P. On the downstream side of the conveyance of the back surface printing unit 5, a conveyance roller 47 for sending out the paper P after the back surface printing is disposed. Then, by the rotation of the transport roller 47, the paper P is transported to the decurling unit 6 on the transport downstream side.

  The decurling unit 6 is for correcting curling of the paper P wound in a roll shape, and includes a conveyance direction regulating guide 61, a decurling roller 48, a decurling guide 62, and a discharge roller 49.

  The leading end of the paper P sent out from the transport roller 47 is guided by the transport direction regulating guide 61 of the decurling unit 6 so as to be sandwiched between the decurling roller 48 and the decurling guide 62. Then, after the curl of the paper P is corrected by the rotation of the decurling roller 48, the decurled paper P is discharged onto the discharge tray 7 by the discharge roller 49.

  In addition to the paper P wound in a roll shape, the printer A is provided with a manual feed tray 81 for the user to manually feed the paper P on the upstream side in the transport direction at the top of the apparatus. A conveyance roller 82 is disposed on the downstream side of the manual feed tray 81 in the conveyance direction, and the paper P accommodated in the manual feed tray 81 by the rotation of the conveyance roller 82 moves along the manual feed guide 83 with the conveyance drive roller 43 and the pair of pressure rollers 44. , 44 so as to be sandwiched between them. Since the following print processing operation is the same as that of the paper P wound in a roll shape, the description is omitted.

  Here, since the paper P conveyed from the manual feed tray 81 is not curled, if the paper P is sent to the decurling roller 48 of the decurling unit 6, the curling is caused by the decurling roller 48. Therefore, a determination unit (not shown) that determines whether the paper P is supplied from the manual feed tray 81 or the paper storage unit 1 is provided, and based on the determination result, the conveyance direction regulation guide 61 It is preferable to control to switch the transport direction. For example, the paper P supplied from the manual feed tray 81 may be controlled to be conveyed in a direction avoiding the passage of the decurling roller 48 and discharged to the discharge tray 7.

  As described above, the present invention provides a highly practical effect that the electromagnetic valve can be reliably opened and closed even when the negative pressure is applied by capping the print head. Therefore, it is extremely useful and has high industrial applicability.

1 is a perspective view showing a part of the configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a plan view showing a part of the configuration of the image forming apparatus with some parts omitted. FIG. 2 is a rear view illustrating the image forming apparatus with a part of the configuration omitted. FIG. 3 is a right side view illustrating the image forming apparatus with a part of the configuration omitted. FIG. 2 is a front view showing a part of the configuration of the image forming apparatus with some parts omitted. FIG. 3 is a side cross-sectional view showing a part of the configuration of the image forming apparatus. It is the II sectional view arrow view of FIG. It is a schematic diagram which shows an ink supply system. It is a perspective view which shows the structure of a cartridge receiving member. It is side surface sectional drawing which shows the structure of a cartridge receiving member. It is side surface sectional drawing which shows the state which open | released the outlet. It is side surface sectional drawing which shows the state which closed the outlet.

Explanation of symbols

A Printer (image forming device)
H Printhead P Paper 1 Paper storage part 2 Print part 3 Ink cartridge mounting part 50 Solenoid valve (opening / closing means)
52 Sub tank 32 Ink cartridge 32b Ink tank 37c Rubber packing

Claims (4)

An ink tank in which ink is stored; a sub tank that is disposed above the ink tank and temporarily stores ink supplied under pressure from the ink tank; and a print head that discharges ink supplied from the sub tank And an ink filling method for an image forming apparatus comprising an opening / closing means for opening / closing an ink flow path between the ink tank and the sub tank,
Supplying a predetermined amount of ink to the ink flow path by opening the opening and closing means in a state where no pressure is applied to the print head while pressurizing the ink tank;
A closing step of closing the opening and closing means after the supplying step;
And a discharging step of discharging the ink in the ink flow path by applying a negative pressure to the print head after the blocking step. In claim 1,
After the discharging step, the ink tank is pressurized, and the first opening and closing means are opened in a state where a negative pressure is applied to the print head, and a first filling step of filling the ink flow path with ink is performed. An ink filling method characterized by the above. In claim 2,
After the first filling step, a negative pressure is applied to the print head with the opening / closing means open, and an ink flow path between the sub tank and the print head via the sub tank and the print An ink filling method comprising performing a second filling step of filling the head with ink. In any one of Claims 1 thru | or 3,
An ink filling method, wherein each of the steps is performed using a cleaning liquid tank in which a cleaning liquid is stored instead of the ink tank in which the ink is stored.

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