JP2015024594A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that: when suction recovery of a head is performed, there is increase in waste liquid consumption.SOLUTION: The image formation device comprises: a recording head 1 having a nozzle 5 for discharging ink droplet; a cap 32 for covering a nozzle surface 1a of the recording head 1; a suction pump 34 for sucking a space in the cap 32; a waste liquid tube 33 for connecting the cap 32 and the suction pump 34; and a suction path filling device 40 for filling the space in the cap 32 and the waste liquid tube 33 with a filling liquid. The suction path filling device 40 comprises: a filling liquid tank 41 for storing the filling liquid; a filling tube 37 for connecting the cap 32 and the filling liquid tank 41; and a liquid feeding pump 44 for feeding the filling liquid to the space in the cap 32 via the filling tube 37 and being disposed on a midway of the filling tube 37. After the space in the cap 32 and a part of the waste liquid tube 33 to the suction pump 34 are filled with the filling liquid by a predetermined amount, the ink is sucked from the nozzle by the suction pump 34.

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus including a liquid discharge head that discharges droplets.

  As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, a plotter, and a complex machine of these, for example, an ink jet recording apparatus is known as an image forming apparatus of a liquid discharge recording method using a recording head for discharging ink droplets. .

  Such an ink jet recording apparatus includes a maintenance / recovery device that maintains and recovers the performance of a liquid discharge head (droplet discharge head) that discharges ink. The maintenance / recovery device includes, for example, a cap that covers the nozzle surface with high airtightness in order to prevent thickening and sticking of ink in the vicinity of the nozzle due to natural evaporation. In addition, there is provided suction means for sucking ink from the nozzle by sucking the space in the cap in a state where the nozzle surface is capped (covered) by the cap. In addition, a waste liquid container (waste liquid tank) is provided for storing waste liquid of ink sucked from the nozzles. In addition, a wiper member for wiping and removing ink adhering to the nozzle surface, an empty discharge receiver for discharging empty droplets that do not contribute to image formation, and the like are provided.

  This maintenance / recovery device is provided in the main body of the apparatus in order to remove the foreign matters adhering to the vicinity of the nozzles and the thickened / fixed liquid droplets and to obtain desired ejection characteristics normally. In particular, the cap keeps the nozzle moist by covering the droplet discharge surface (nozzle surface) after the printing operation in order to prevent moisture contained in the liquid in the nozzle from drying when the image forming apparatus is not used for a long time. Yes.

  When suction is performed by the suction means with the cap covering the nozzle surface, negative pressure is generated in the cap. Due to this negative pressure, the liquid passes from the liquid tank through the nozzle and flows into the waste liquid tank. At this time, the foreign matter in the vicinity of the nozzle and the thickened / fixed liquid can be flowed to the waste liquid tank. In addition, bubbles remaining in the flow path from the liquid tank to the nozzle of the liquid discharge head can be discharged.

  By the way, when recovering a liquid discharge head that has failed to be discharged by cap suction, if air is present in the path from the cap to the suction means, the air expands when sucked, so the suction pressure is applied to the liquid discharge head. Becomes difficult to act. Moreover, there is a problem that ink is consumed more than the amount of air expansion.

  Therefore, it is conventionally known that the waste liquid is caused to flow back to the cap from the waste liquid tank and then recovered by suction (Patent Document 1).

JP 2008-126554 A

  However, in the method described in Patent Document 1, there is a possibility that the waste liquid touches the nozzle surface and the nozzle surface becomes dirty. In this case, in order not to touch the nozzle surface, it is necessary to leave an air layer in the upper part of the cap (nozzle surface side), and there is a problem that the effect of reducing wasteful ink consumption is not sufficient.

  The present invention has been made in view of the above problems, and an object of the present invention is to enable efficient suction recovery with less wasteful liquid consumption.

In order to solve the above problems, an image forming apparatus according to claim 1 of the present invention provides:
A liquid discharge head having a nozzle for discharging a first liquid droplet;
A cap that covers the nozzle surface of the liquid discharge head;
A suction means for sucking a space in the cap;
A suction flow path connecting the cap and the suction means;
A channel filling means for filling the space inside the cap and the suction channel with a second liquid,
The channel filling means includes
A liquid storage container for storing the second liquid;
A filling flow path connecting the cap and the liquid container;
Liquid feeding means provided in the middle of the filling flow path, for feeding the second liquid to the cap internal space through the filling flow path,
The first liquid is sucked from the nozzle by the suction means after the inner space of the cap and the suction flow path are filled with the second liquid by the flow path filling means.

  According to the present invention, wasteful liquid consumption is small and efficient suction recovery can be performed.

1 is a schematic plan view illustrating an ink jet recording apparatus as an image forming apparatus according to an embodiment of the present invention. It is a schematic front explanatory drawing similarly. It is a schematic side surface explanatory drawing similarly. FIG. 2 is an enlarged explanatory view of a main part for explaining a recording head of the same apparatus. It is typical sectional explanatory drawing which shows an example of the head tank of the same apparatus. It is typical explanatory drawing with which it uses for description of a suction route filling device. FIG. 6 is a schematic explanatory diagram for explaining a suction recovery operation with respect to the recording head in the embodiment. It is typical explanatory drawing with which it uses for description of 2nd Embodiment of this invention. It is typical explanatory drawing with which it uses for description of 3rd Embodiment of this invention. FIG. 6 is a schematic explanatory diagram for explaining a suction recovery operation with respect to the recording head in the embodiment. It is typical explanatory drawing with which it uses for description following FIG. It is typical explanatory drawing with which it uses for description of 4th Embodiment of this invention. FIG. 6 is a schematic explanatory diagram for explaining a suction recovery operation with respect to the recording head in the embodiment. FIG. 14 is a schematic explanatory diagram for explanation following FIG. 13. FIG. 15 is a schematic explanatory diagram for explanation following FIG. 14. It is typical explanatory drawing with which it uses for description of 5th Embodiment of this invention. FIG. 6 is a schematic explanatory diagram for explaining a suction recovery operation with respect to the recording head of the same embodiment. FIG. 18 is a schematic explanatory diagram for explanation following FIG. 17.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An ink jet recording apparatus as an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIGS. 1 is a schematic plan view of the recording apparatus, FIG. 2 is a schematic front view, and FIG. 3 is a schematic side view.

  This ink jet recording apparatus includes a guide rod 122 that is a guide member spanned between left and right side plates 123L and 123R that are erected on a main body frame 30, and a guide rail that is attached to a rear frame 128 that is disposed on the main body frame 30. 124, the carriage 120 is held movably in the main scanning direction (guide rod longitudinal direction). The carriage 120 is moved and scanned in the longitudinal direction (main scanning direction) of the guide rod 122 by a main scanning motor (not shown) and a timing belt.

  The carriage 120 includes, for example, one or a plurality of liquid ejection heads that eject ink droplets that are first liquids of black (K), cyan (C), magenta (M), and yellow (Y). A recording head 1 is mounted. The recording head 1 is mounted with a plurality of ink ejection openings (nozzles) arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.

  Here, as shown in FIG. 4, the recording head 1 is composed of a heating element substrate 2 and a liquid chamber forming member 3, and a common channel 7 and a liquid chamber via an ink supply path formed on the heating element substrate 2. (Individual channel) The ink sequentially supplied to 6 is ejected as droplets. This recording head 1 is a thermal type that obtains a discharge pressure by boiling an ink film by driving a heating element 4, and the direction of ink flow to the discharge energy acting part (heating element part) in the liquid chamber 6 and the nozzles. 5 is a side shooter type configuration in which the central axis of the opening 5 is a right angle.

  As the recording head, there are various methods such as a method in which the diaphragm is deformed by using a piezoelectric element, and the diaphragm is deformed by an electrostatic force to obtain a discharge pressure. The present invention can be applied to such an image forming apparatus.

  On the other hand, below the carriage 120, the paper 8 on which an image is formed by the recording head 1 is conveyed in a direction perpendicular to the main scanning direction (sub-scanning direction). As shown in FIG. 3, the paper 8 is sandwiched between a transport roller 125 and a presser roller 126, transported to an image forming area (printing unit) by the recording head 1, sent onto a printing guide member 129, and discharged. A pair of rollers 127 feeds in the paper discharge direction.

  At this time, the scanning of the carriage 120 in the main scanning direction and the ink ejection from the recording head 1 are synchronized at an appropriate timing based on the image data, and an image for one band is formed on the paper 8. After image formation for one band is completed, a predetermined amount of paper 8 is fed in the sub-scanning direction, and the same recording operation as described above is performed. These operations are repeated to form an image for one page.

  On the other hand, a head tank (buffer tank, sub tank, flow path forming member) 101 in which an ink chamber for temporarily storing ink to be ejected is formed is integrally connected to the upper portion of the recording head 1. Here, “integral” includes that the recording head 1 and the head tank 101 are connected by a tube, a tube, or the like, and both are mounted on the carriage 120 together.

  For example, as shown in FIG. 5, the head tank 101 is provided with a filter 109 in the vicinity of the connection portion with the recording head 1, and supplies the recording head 1 with ink that has been filtered to remove foreign matters. Further, a film member 107 that can be bent is provided on one wall surface of the head tank 101.

  A liquid supply tube 71 is connected to the head tank 101. As shown in FIG. 1, the other end of the liquid supply tube 71 is connected to a main body stationary cartridge holder 77 which is a liquid tank as a liquid storage container. An ink cartridge (main tank) 76, which is a liquid tank as a liquid storage container containing ink of each color, is detachably mounted on the cartridge holder 77.

  A maintenance / recovery mechanism (a maintenance / recovery device) 31 that performs maintenance / recovery of the recording head 1 is disposed on the other end side in the main scanning direction of the apparatus main body.

  The maintenance / recovery mechanism 31 includes a cap 32 that covers (covers) the nozzle surface of the recording head 1 and a suction pump 34 that is a suction unit that sucks the inside of the cap 32 and sucks ink from the nozzles 5 of the recording head 1. I have. The ink waste liquid sucked by the suction pump 34 is discharged to a waste liquid tank 36 which is a waste liquid container disposed on the main body frame 30 side. The cap 32, the suction pump 34, and the waste liquid tank 36 are connected by a waste liquid tube 33 serving as a discharge path. In the waste liquid tube 33, a suction path is formed between the cap 32 and the suction pump 34, and a waste liquid path is formed between the suction pump 34 and the waste liquid tank 36.

  The maintenance / recovery mechanism 31 includes a moving mechanism for moving the cap 32 forward and backward (in this example, ascending and descending) with respect to the nozzle surface of the recording head 1. Further, although not shown, the maintenance / recovery mechanism 31 is provided with a wiper member that wipes the nozzle surface of the recording head 1 by a wiping unit so as to be able to advance and retreat relative to the nozzle surface.

  In addition, the image forming apparatus includes a suction path filling device 40 which is a flow path filling unit adjacent to the maintenance / recovery device 31.

  Next, the suction path filling device 40 will be described with reference to FIG. FIG. 6 is a schematic explanatory diagram for explaining the apparatus.

  The suction path filling device 40 includes a filling liquid tank 41 that is a liquid container that contains a liquid to be filled (second liquid), and a filling tube 37 that is a filling flow path through the filling liquid tank 41 and the cap 32. The filling pump 44 is a liquid feeding means provided in the filling tube 37.

  Here, the filling tube 37 is connected to the filling port 43 of the cap 32. Further, the waste liquid tube 33 of the above-described maintenance / recovery device 31 is connected to the suction port 42 of the cap 32.

  In addition, although various things can be used as a liquid (filling liquid) with which it fills, water is preferable at the point of an inexpensive liquid. In addition, since it comes into contact with the nozzle surface and the suction path of the recording head 1, a cleaning liquid may be used in terms of cleaning those parts. In addition, as the filling liquid tank 41, a tank that communicates with the atmosphere is preferable in terms of facilitating replenishment, but a bag-like member that can be bent can also be used.

  Next, the suction recovery operation for the recording head in this embodiment will be described with reference to FIG. FIG. 7 is a schematic explanatory view for explaining the same.

  First, only the filling pump 44 is driven in a state where the cap 32 is separated from the nozzle surface of the recording head 1. As a result, as shown in FIG. 7A, the filling liquid 500 flows into the cap 32 from the filling port 43 provided at the bottom of the cap 32.

  Thereafter, the suction pump 34 is driven while the filling pump 44 is driven. As a result, the filling liquid 500 in the cap 32 flows out from the suction port 42 provided at the bottom of the cap 32 to the waste liquid tube 33 as shown in FIG.

  Here, the liquid feeding flow rate of the filling pump 44 and the liquid feeding flow rate of the suction pump 34 are substantially the same. Therefore, the waste liquid tube 33 is filled with the filling liquid 500 while the liquid level of the filling liquid 500 in the cap 32 is kept substantially constant.

  Then, when the time for the filling liquid 500 to reach the suction pump 34 has elapsed, only the suction pump 34 is stopped. Then, as shown in FIG. 7C, the liquid level of the filling liquid in the cap 32 rises again, the cap 32 is completely filled, and the filling liquid 500 overflows from the edge of the cap 32. The overflowing filling liquid 500 is guided to the waste liquid tank 36 through a waste liquid guide path (not shown).

  Then, after the filling pump 44 is stopped, the cap 32 is raised to cap the recording head 1 and only the suction pump 34 is driven to suck ink from the nozzle 5 (this is referred to as “nozzle suction”).

  Thus, the suction space (the inside of the cap 32 and the waste liquid tube 33) on the upstream side of the suction pump 34 when the nozzle suction is performed is filled with the liquid in advance. As a result, the pressure (negative pressure) generated by driving the suction pump 34 is not damped by air, so that it acts on the inside of the recording head 1 efficiently.

  Accordingly, since a large negative pressure can be applied to the recording head 1 simultaneously with the driving of the suction pump 34, it is not necessary to perform unnecessary suction, and the suction recovery of the recording head 1 can be performed in a short time.

  Further, since unnecessary suction is not required, the amount of ink consumed for recovery of suction of the recording head 1 can be reduced. Further, since water or a cleaning liquid can be used as the filling liquid, the effect of cleaning the nozzle surface by a wiping operation that is normally performed after suction is also obtained by immersing the recording head 1 in these liquids.

  In this embodiment, the filling pump 44 and the suction pump 34 have the same liquid flow rate, and after the filling pump 44 is driven in advance, both pumps are driven simultaneously to fill the waste liquid tube 33, and then only the suction pump 34 is turned on. The cap 32 is filled after stopping, but the filling method is not limited to this.

  For example, if the filling pump 44 is a pump having a larger flow rate than the suction pump 34, the two pumps can be driven simultaneously to fill both the cap 32 and the waste liquid tube 33, and the pump control is simplified.

  If the volume of the cap 32 is larger than the upstream volume of the suction pump 34 in the waste liquid tube 33, the filling pump 44 is driven to fill the cap 32, and then the filling pump 44 is temporarily stopped. By driving only the liquid tube 33 and filling the waste liquid tube 33 with the filling liquid and again driving only the filling pump 44 to refill the cap 32, the entire suction path can be filled with the filling liquid. According to this method, since it is not necessary to drive two pumps at the same time, for example, it is possible to switch pumps driven in the rotational direction of a motor that operates the pumps, and to reduce the cost of the apparatus by using a common drive source. Can do.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a schematic explanatory diagram for explaining the embodiment.

  In the present embodiment, an overflow receiving portion 45 that is a liquid receiver that receives the filling liquid 500 overflowing from the cap 32 is provided below the cap 32 (downward in the direction of gravity). The overflow receiving portion 45 has a mortar shape inside, and a drain hole 46 is provided at the bottom.

  The overflow receiving portion 45 is configured to move up and down together with the cap 32.

  Further, a plug member 47 that opens and closes the drain hole 46 is disposed below the overflow receiving portion 45. Here, when the cap 32 is separated from the recording head 1, the drain hole 46 is sealed with a stopper 47 as shown in FIG. 8A, and as shown in FIG. When 32 is raised, the drain hole 46 is separated from the plug 47 and the seal is not released.

  In addition, a pair of liquid detection electrode pins 48 serving as liquid detection means for detecting the presence or absence of liquid is provided in the middle portion of the inclined surface of the overflow receiving portion 45. The electrical resistance between the two liquid detection electrode pins 48, 48 can be measured by a resistance detector 49.

  The configuration other than the periphery of the cap 32 is the same as that in the first embodiment.

  Next, the suction path filling and the recovery operation for the recording head 1 in the present embodiment will be described.

  First, FIG. 8A shows a state in which only the filling pump 44 is driven and the filling liquid 500 is supplied into the cap 32 in a state where the cap 32 is separated from the recording head 1. At this time, there is no filling liquid in the overflow receiving portion 45, and the two liquid detection electrode pins 48 are air-insulated.

  FIG. 8B shows a state where both the filling pump 44 and the suction pump 34 are driven to fill the flow path between the suction port 42 and the suction pump 34.

  FIG. 8C again shows a state in which only the filling pump 44 is driven to supply the filling liquid into the cap 32. When the cap 32 is separated from the recording head 1, since the drain hole 46 is sealed with the stopper 47, the filling liquid 500 overflowing from the edge of the cap 32 flows and accumulates in the overflow receiving portion 45.

  Then, as shown in FIG. 8C, when the filling liquid 500 is interposed between the pair of liquid detection electrode pins 48, the electrical resistance between the liquid detection electrode pins 48 decreases, and this resistance value change is caused. It is detected by the resistance detector 49. Therefore, the filling pump 44 is stopped using the detection of the resistance value drop by the resistance detector 49 as a trigger.

  Next, as shown in FIG. 8D, the cap 32 is brought into contact with the nozzle surface of the recording head 1 for capping, and the suction pump 34 is driven to perform nozzle suction.

  Also in this embodiment, as in the first embodiment, since the suction path is filled with liquid in advance, a large suction pressure can be obtained with a small suction amount, and the recording head is efficient and has a small amount of ink consumption. 1 performance can be restored.

  When the recording head 1 is suctioned, the cap 32 is lifted so that the drain hole 46 of the overflow receiving portion 45 is separated from the plug 47, so that the filling liquid 500 accumulated from the drain hole 46 is discharged. And the state is reset for the next recovery operation.

  As described above, in the present embodiment, since the detection means for detecting the completion of the filling into the cap 32 is provided, even if the performance of the filling pump 44 varies, the completion of the filling is accurately detected, and the filling step Can be performed stably.

  If the filling liquid in the filling liquid tank 41 is insufficient, the resistance detector 49 does not detect a change in resistance between the liquid detection electrode pins 48 even if the filling pump 44 is driven for a predetermined time in the filling process of the cap 32. It will be. Thereby, it can be detected that the filling liquid tank 41 is empty.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 9 is a schematic explanatory diagram for explaining the embodiment.

  In the present embodiment, in the first embodiment, a filling flow path opening / closing valve 50 and a backflow prevention buffer 54 that is a volume variable member are provided in the middle of the filling tube 37.

  The backflow prevention buffer 54 is a shrinkable container in which liquid can freely enter and exit, and shrinks when the internal pressure becomes negative, and expands to its original shape when the negative pressure decreases. The bellows structure or the like can be used. The backflow prevention buffer 54 is preferably disposed below the cap 32.

  A liquid detection sensor 53 is provided in the middle of the waste liquid tube 33. Although the detailed configuration of the liquid detection sensor 53 is not shown, the liquid detection sensor 53 may be configured to detect a change in electrical resistance as in the second embodiment.

  Further, the opening 42 a to the cap internal space of the suction port 42 of the cap 32 is disposed in the vicinity of the nip portion 32 a that comes into contact with the nozzle surface of the recording head 1 of the cap 32. Thereby, when the nozzle surface is capped with the cap 32, a minute gap is formed between the opening 42 a of the suction port 42 and the nozzle surface of the recording head 1.

  Next, the suction recovery operation for the recording head 1 in this embodiment will be described with reference to FIGS.

  First, as shown in FIG. 10A, the suction pump 34 is driven while the recording head 1 and the cap 32 are separated from each other. At this time, the backflow prevention buffer 54 is in an expanded state because the filling port 43 is at atmospheric pressure regardless of whether the filling flow path opening / closing valve 50 is opened or closed. Since air flows from the suction port 42, the liquid in the waste tube 33 is discharged, and the liquid detection sensor 53 detects “no liquid”.

  Thereafter, as shown in FIG. 10B, the cap 32 is raised, the nozzle surface of the recording head 1 is capped, and the internal space of the cap 32 is sealed. In this state, the filling channel opening / closing valve 50 is opened and suction is performed by the suction pump 34. Thereby, the filling liquid 500 in the filling liquid tank 41 is sucked and flows into the cap 32. At this time, if the thickness of the filling tube 37 is sufficiently large, the pressure loss in the filling tube 37 is small, so that the inside of the backflow prevention buffer 54 does not become a large negative pressure and maintains the volume.

  In the cap 32 of this embodiment, since the opening 42a of the suction port 42 is located above the cap 32, the air in the cap 32 is discharged, and the cap 32 is filled as shown in FIG. After filling with the liquid 500, the waste liquid tube 33 is filled with the filling liquid 500.

  Then, the suction pump 34 is stopped with the liquid detection sensor 53 detecting the liquid as a trigger. As a result, the suction path is completely filled with the liquid.

  Thereafter, as shown in FIG. 11 (b), the filling flow path opening / closing valve 50 is closed and suction is performed by the suction pump 34. Thereby, since the upstream side of the recording head 1 has a high resistance, a large negative pressure is generated in the suction path.

  Here, if the backflow prevention buffer 54 is configured so as to be deformed at a pressure smaller than the pressure loss when ink is sucked from the nozzles 5 of the recording head 1, the backflow prevention buffer 54 is first caused by the negative pressure generated by suction. Shrinks, the liquid inside is discharged, and it is completely crushed. Thereafter, a negative pressure is applied to the recording head 1 so that the suction recovery of the recording head 1 can be performed.

  After the suction recovery, the cap 32 is separated from the recording head 1 and the nozzle surface is wiped with a wiper member (not shown).

  Since the cap 32 returns to atmospheric pressure when it is not in the capping state, the liquid (ink and filling liquid) in the cap 32 flows back through the filling tube 37. At this time, the backflow prevention buffer 54 collects the backflowed liquid while expanding, so that the ink does not flow to the filling liquid tank 41, and the filling liquid 500 in the filling liquid tank 41 can be kept clean. In order to obtain such an effect sufficiently, the variable volume of the backflow prevention buffer 54 is preferably larger than the volume of the cap 32.

  In this embodiment, it is possible to fill the suction path and recover the suction of the recording head 1 with only the suction pump 34, and the same effect as in the above-described embodiment can be obtained. Further, since the liquid detection sensor 53 is provided in the waste liquid tube 33, the recovery operation can be performed without wasted time even if the suction pumps 34 vary.

  Further, when the filling liquid in the filling liquid tank 41 is insufficient, the liquid detection sensor 53 detects that the flow path is filled with liquid even if the filling pump 44 is driven for a predetermined time in the filling process of the waste liquid tube 33. Will not. Therefore, it can be detected that the filling liquid tank 41 is empty.

  Further, since the backflow prevention buffer 54 is provided, the waste liquid that has filled the cap 32 at the time of suction recovery is collected in the backflow prevention buffer 54 and the liquid level in the cap 32 is lowered, so that the recording head 1 is capped after the recovery operation. This prevents the nozzle surface from coming into contact with the waste liquid again. Further, it is possible to prevent the waste liquid from being mixed into the filling liquid tank 41.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 12 is a schematic explanatory diagram for explaining the embodiment.

  In the present embodiment, a choke valve 56 is provided in the middle of the supply path (supply tube 71) of the recording head 1, so that the ink supply path can be blocked.

  The filling tube 37 is provided with a check valve 55.

  The cap 32 is provided with a suction port 42 at a substantially central portion, and a slit 57 is formed on the end surface of the suction port 42 on the recording head 1 side. A thin portion 58 is formed around the suction port 42 of the cap 32.

  As a result, the suction port 42 that is a portion communicating with the suction flow path (waste liquid tube 33) in the cap 32 when the suction pump 34 sucks the space in the cap formed with the nozzle 32 covering the nozzle surface. Move upward. The suction port 42, which is a portion communicating with the suction flow path (waste liquid tube 33) in the cap 32, has a tubular shape and is opened laterally by a slit 57.

  Next, the suction recovery operation for the recording head 1 in the present embodiment will be described with reference to FIGS.

  First, as shown in FIG. 13A, the suction pump 34 is driven while the recording head 1 and the cap 32 are separated from each other. Since air flows from the suction port 42, the liquid in the waste tube 33 is discharged, and the liquid detection sensor 53 detects “no liquid”.

  Then, as shown in FIG. 13B, the cap 32 is raised, the recording head 1 is capped, and the inside of the cap 32 is sealed. Further, the choke valve 56 is closed to shut off the supply path. In this state, the filling channel opening / closing valve 50 is opened and suction is performed by the suction pump 34. Thereby, the filling liquid 500 in the filling liquid tank 41 is sucked and flows into the cap 32.

  Further, since the choke valve 56 is closed and ink is not supplied from the recording head 1, the inside of the cap 32 becomes negative pressure, the thin portion 58 formed at the bottom of the cap 32 is bent, and the suction port 42 is displaced toward the recording head 1. , Hit and contact. Thereby, the volume in the cap 32 decreases. At this time, since the slit 57 is formed in the end face of the suction port 42, air is sucked from the uppermost part of the space in the cap through the slit 57 and discharged to the waste liquid tube 33, as shown in FIG. As described above, the cap 32 is completely filled with the filling liquid 500. Thereafter, the waste liquid tube 33 is filled with the filling liquid 500.

  Then, the suction pump 34 is stopped using the detection of the liquid by the liquid detection sensor 53 as a trigger. As a result, the suction path is completely filled with the liquid.

  Thereafter, as shown in FIG. 14B, the filling flow path opening / closing valve 50 is closed, the choke valve 56 is opened, and suction is performed by the suction pump 34. Then, ink is supplied from the upstream side of the recording head 1 and suction recovery of the recording head 1 is performed.

  After the suction recovery, the cap 32 is separated from the recording head 1 and the nozzle surface is wiped with a wiper member (not shown).

  Since the cap 32 returns to atmospheric pressure when it is not in the capping state, in this embodiment, since the check tube 55 is provided in the filling tube 37, the liquid (ink and filling liquid) in the cap 32 is filled with the filling tube. 37 can be prevented from flowing back into the filling liquid tank 41. Thereby, the filling liquid 500 in the filling liquid tank 41 can be kept clean.

  Further, when the inside of the cap 32 returns to the atmospheric pressure, the deformation of the thin portion 58 of the cap 32 is restored, the volume in the cap 32 is restored to the original volume, and the position of the suction port 42 is lowered.

  Therefore, as shown in FIG. 15, since the liquid level in the cap 32 can be lowered by driving the suction pump 34, the nozzle surface comes into contact with the waste liquid again when the recording head 1 is capped after the recovery operation. Can be prevented.

  Further, in the present embodiment, the suction path can be filled and the recording head 1 can be sucked and recovered only by the suction pump 34, and the same effects as those of the above-described embodiment can be obtained. Further, since the liquid detection sensor 53 is provided in the waste liquid tube 33, the recovery operation can be performed without wasted time even if the suction pumps 34 vary.

  In the present embodiment, the choke valve 56 is provided in the ink supply path and the choke valve 56 is closed during the filling process of the filling liquid to shut off the ink supply. However, the choke valve 56 is not essential. In short, if the relationship of “pressure loss upstream of the recording head when ink is sucked from the recording head”> “pressure loss of the filling tube during suction of the filling liquid”> “pressure necessary for deformation of the cap” is satisfied. The present invention can be applied.

  Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 16 is a schematic explanatory diagram for explaining the embodiment.

  In the present embodiment, both the filling liquid tank 41 and the waste liquid tank 36 are opened to the atmosphere in the fourth embodiment, whereas both the filling liquid tank 41 and the waste liquid tank 36 can be sealed. It is said.

  That is, the filling liquid tank 41 is opened to the atmosphere only when the filling liquid replenishing port 39 is opened to replenish the filling liquid 500, but is normally sealed when the filling flow path opening / closing valve 50 is closed. ing. Further, the waste liquid tank 36 is provided with an air release path 59 that communicates with the atmosphere inside the tank and an air release valve 51 that opens and closes the tank. The air release valve 51 is in a sealed state when the air release valve 51 is closed. However, since these two tanks are connected by the pressure transmission flow path 52 at the upper part, both have the same pressure.

  Next, the suction recovery operation for the recording head 1 of this embodiment will be described with reference to FIGS.

  First, as shown in FIG. 17A, the air release valve 51 is opened with the recording head 1 and the cap 32 being separated from each other, and the suction pump 34 is driven. At this time, the backflow prevention buffer 54 is in an expanded state because the filling port 43 is at atmospheric pressure regardless of whether the filling flow path opening / closing valve 50 is opened or closed. Since air flows from the suction port 42, the liquid in the waste tube 33 is discharged, and the liquid detection sensor 53 detects “no liquid”.

  Next, as shown in FIG. 17B, the cap 32 is raised, the recording head 1 is capped, and the internal space of the cap 32 is sealed. In this state, the air release valve 51 is closed, the filling flow path opening / closing valve 50 is opened, and suction is performed by the suction pump 34. Thereby, the filling liquid in the filling liquid tank 41 is sucked and flows into the cap 32.

  At this time, the pressure of the waste liquid tank 36 is increased by the air or the liquid flowing into the waste liquid tank 36, so that the pressure acts on the filling liquid tank 41 via the pressure transmission flow path. Therefore, the supply of the filling liquid 500 to the cap 32 portion is assisted. As a result, the pressure loss in the filling tube 37 is reduced, so that the backflow prevention buffer 54 does not have a large negative pressure and maintains its volume.

  In the cap 32 of the present embodiment, since the suction port 42 is located at the upper part in the cap 32, the air in the cap 32 is discharged, and the cap 32 is filled with the filling liquid 500 as shown in FIG. Thereafter, the waste liquid tube 33 is filled with the filling liquid 500.

  Then, the suction pump 34 is stopped using the detection of the liquid by the liquid detection sensor 53 as a trigger. As a result, the suction path is completely filled with the liquid.

  Thereafter, as shown in FIG. 18B, the filling flow path opening / closing valve 50 is closed, the air release valve 51 is opened, and suction is performed by the suction pump 34. As a result, since the upstream side of the recording head 1 has a high resistance, a large negative pressure is generated in the suction path.

  At this time, if the backflow prevention buffer 54 is configured to be deformed at a pressure smaller than the pressure loss when ink is sucked from the nozzles 5 of the recording head 1, the backflow prevention buffer 54 first contracts due to the negative pressure generated by the suction. Then, the liquid inside is discharged and completely collapsed.

  After that, a negative pressure acts on the recording head 1, and the suction recovery of the recording head 1 can be performed. After the suction recovery, the cap 32 is separated from the recording head 1 and the nozzle surface is sucked with a wiper (not shown). Since the cap returns to atmospheric pressure when it is not in the capping state, the liquid (ink and filling liquid) in the cap flows back through the filling tube 37. At this time, since the backflow prevention buffer 54 collects the backflowed liquid while expanding, the ink does not flow into the filling liquid tank 41 and the filling liquid in the filling liquid tank 41 can be kept clean.

  In the present embodiment, in addition to the effect of the embodiment of FIG. 9, the pressure assist is performed at the time of filling the filling liquid, so that the design restriction of the filling device can be relaxed. Specifically, it is possible to increase the degree of freedom in arranging the filling liquid tank 41 by allowing the filling liquid to be highly viscous or making the filling path long and narrow.

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

  The “image forming apparatus” means an apparatus that forms an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics or the like. 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 “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically. For example, 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.

1 Recording head (liquid ejection head)
31 Maintenance and recovery mechanism 32 Cap 33 Waste liquid tube (suction flow path, waste liquid flow path)
34 Suction pump (suction means)
36 Waste liquid tank (waste liquid container)
37 Filling tube (filling flow path)
40 Suction path filling device (flow path filling means)
41 Filling liquid tank (liquid container)
44 Filling pump (liquid feeding means)
71 Supply tube 76 Ink cartridge 101 Head tank

Claims (9)

A liquid discharge head having a nozzle for discharging a first liquid droplet;
A cap that covers the nozzle surface of the liquid discharge head;
A suction means for sucking a space in the cap;
A suction flow path connecting the cap and the suction means;
A channel filling means for filling the space inside the cap and the suction channel with a second liquid,
The channel filling means includes
A liquid storage container for storing the second liquid;
A filling flow path connecting the cap and the liquid container;
Liquid feeding means provided in the middle of the filling flow path, for feeding the second liquid to the cap internal space through the filling flow path,
The first liquid is sucked from the nozzle by the suction means after the space inside the cap and the suction flow path are filled with a predetermined amount of the second liquid by the flow path filling means. apparatus. A liquid discharge head having a nozzle for discharging a first liquid droplet;
A cap that covers the nozzle surface of the liquid discharge head;
A suction means for sucking a space in the cap;
A suction flow path connecting the cap and the suction means;
A waste liquid container for storing the waste liquid sucked by the suction means;
A waste liquid flow path connecting the suction means and the waste liquid container;
A channel filling means for filling the space inside the cap and the suction channel with a second liquid,
The channel filling means includes
A liquid storage container for storing the second liquid;
A filling flow path connecting the cap and the liquid container;
An open / close valve that opens and closes the flow path provided in the filling flow path,
After the on-off valve is opened and sucked by the suction means, the space inside the cap and the suction flow path are filled with the second liquid by a predetermined amount, and then the on-off valve is closed, An image forming apparatus, wherein the first liquid is sucked from the nozzle by suction means. A passage connecting the liquid container and the waste liquid container;
An open air path leading to the atmosphere through at least one of the liquid container and the waste liquid container;
The image forming apparatus according to claim 2, further comprising an atmosphere release valve that opens and closes the atmosphere release path. A liquid receiver is provided below the cap;
The image forming apparatus according to claim 1, wherein the liquid receiver is provided with a liquid detection unit that detects the presence or absence of liquid.   The image forming apparatus according to claim 1, wherein a liquid detection unit that detects the presence or absence of liquid is provided in the cap or the suction channel. 4. The image forming apparatus according to claim 2, wherein a portion of the cap that communicates with the suction flow path is provided at a position spaced apart from a portion that contacts the nozzle surface. The portion that communicates with the suction flow path in the cap moves upward when the suction means sucks the space in the cap formed in a state where the nozzle surface is covered with the cap. The image forming apparatus according to 2 or 3. The image forming apparatus according to claim 7, wherein a portion of the cap that communicates with the suction flow path has a tubular shape and opens laterally. The image forming apparatus according to claim 2, wherein the filling flow path is provided with a check valve or a variable volume member.

Images