JPH1191138A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a piled pigment-based ink from being formed into a stalagmitic shape, by sliding a discharge point in association with the movement of a carriage thereby carrying out an idle discharge of ink when the pigment- based ink is to be discharged to an idle discharge container. SOLUTION: A carriage 110 is moved to an idle discharge container 128, and a one-dot quantity of ink is discharged from each nozzle hole to a recording head 111 at a first idle discharge position KP1. The carriage does not stand still even at the KP1 and keeps moving. Even when the carriage 110 moves by one dot from the KP1 towards the other end of an opening part of the idle discharge container 128, the recording head 111 discharges ink of only one dot from each nozzle hole. In other words, an idle discharge position is slid by every one dot from one end to the other end of the opening part of the idle discharge container 128 while the carriage 110 is moved. Ink of one dot is discharge from each nozzle hole at each idle discharge position. A predetermined count of dots are thus discharged idly, so that a piled substance 300 of ink does not become a stalagmitic shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle discharge means of an ink jet recording apparatus for forming an ink image on a recording medium such as recording paper by flying pigment-based ink droplets.

[0002]

2. Description of the Related Art In general, an ink jet recording apparatus is provided with a process called "empty discharge" in order to prevent ink clogging of a recording head, and is periodically provided in a container called "empty discharge container" provided in a print recovery device. A plurality of dots of ink droplets are ejected from each nozzle. Here, FIG. 4 is a cross-sectional view of the conventional empty discharge container when the empty discharge position is one place. When the discharge operation is continued to a specific point of the empty discharge container 128 using the pigment-based ink, Resin components such as the dispersant of the discharged pigment-based ink do not evaporate but remain and accumulate, and the ink accumulation 300 gradually becomes stalagmite-like. This eventually grows so as to come into contact with the recording head 111, and causes movement of the recording head, impairs print quality, or causes clogging of nozzles. This ink accumulation 3
Since 00 accumulates in the upper direction regardless of the width direction, even if the width of the empty discharge container 128 is increased as shown in the figure, the problem is not solved at all. In addition, since they are only accumulated locally, a wasteful space is created in the empty discharge container, and the container itself must be unnecessarily enlarged, which is a very important problem for miniaturization. As a countermeasure, if there is room in the vertical direction of the inkjet recording device,
For example, Japanese Patent Application Laid-Open No. 8-230200 shows an example in which a movable empty discharge container is used. However, this example also has a margin in the vertical direction, which makes it difficult to design a thin or small inkjet recording apparatus.

[0003]

In the case of a small or thin ink jet recording apparatus, a movable empty discharge container becomes a structural bottleneck, and the reliability tends to be impaired due to complexity. SUMMARY OF THE INVENTION An object of the present invention is to provide a reliable ink jet recording apparatus without making the structure of an empty discharge container special, and preventing an ink accumulation of a pigment-based ink from forming stalagmites. It is in.

[0004]

In order to solve the above problem, an ink jet recording apparatus according to the present invention slides a discharge point in conjunction with movement of a carriage when discharging a pigment-based ink to an empty discharge container. Idle discharge of the ink.

[0005]

FIG. 1 is a perspective view of a portion of a print recovery device of the ink jet recording apparatus, and FIG. 2 is a sectional view of the portion. Hereinafter, the schematic configuration of the ink jet recording apparatus will be described with reference to these drawings. A recording head 111 is placed on a carriage 110 that moves along a carriage shaft 113.
Is installed. A print recovery device 120 is provided at the home position HP (left side of the position recording surface in the illustrated example) of the carriage.

The print recovery device 120 is mainly provided with a cap 121 that is driven forward and backward with respect to the recording head 111 to seal the nozzle surface 112 (the surface on which the ink discharge ports are formed) of the recording head at the forward position, and a cap 121. A pump (not shown) that sucks ink from nozzles through a suction tube 123 provided in the cap holder 122.
A flexible wiper 124 provided on the side surface of the cap 121 for wiping the nozzle surface 112 of the recording head, and an empty discharge container 128 provided on the side surface of the wiper for performing idle discharge.

The cap 121 and the wiper 124 are moved forward and backward by the eccentric cam 126 to move the cap holder 122 and the wiper holder 125 to which the cap 121 and the wiper 124 are attached. The eccentric cam for controlling the cap and the eccentric cam for controlling the wiper are attached to the same camshaft 127, so that the timing of the forward and backward movement of each other is set.

The wiper 124 is a flexible blade made of rubber, a plastic seal, or the like, and has a length that overlaps the nozzle surface 112 of the recording head by about 1 to 3 mm at the advanced position.

Also, a replaceable ink cartridge 2 containing a pigment-based ink in a plastic molded container.
00 is mounted on the cartridge holder 114 on the recording head.

The empty discharge container 128 is a stationary container made of plastic or metal, and is often a base 130.
And the base 13 by screwing and bonding
It is fixed to 0. In addition, an opening is provided on the surface facing the nozzle surface 112, and the outer peripheral portion is chamfered to prevent idlely discharged ink droplets from accumulating on the outer peripheral portion on the upper surface of the container.

Next, the printing recovery operation of the printing recovery device will be described. When the carriage 110 comes to the home position HP of the print recovery device 120 from the print surface 150, the cap 1
21 and the wiper 124 are retracted. When the carriage 110 comes to the home position HP, the eccentric cam 126 is rotated by the power of a motor (not shown) to advance the cap 121 to seal the nozzle surface 112. Next, a suction pump (not shown) is driven to suck ink in the recording head from a suction tube 123 provided in the cap holder 122. The suction fills the recording head 111 with ink, removes air bubbles mixed in the head by a printing operation, and the like.

When the ink suction operation is completed, the eccentric cam 126 is rotated again to retract the cap 121. At this time, the eccentric cam for the wiper should be shaped to move forward,
The wiper 124 moves forward with the retraction of the cap 121. Next, in this state, the carriage 110 is moved from the home position HP in the printing surface direction 150 (right side in the figure). At this time, the nozzle surface 112 of the recording head is
By passing over the nozzle surface 4, the nozzle surface 112 is removed, and the ink adhered to the nozzle surface during ink suction is wiped off to be clean. Further, in order to stabilize the meniscus and remove dust and bubbles that could not be removed at the time of ink suction, the carriage 110 is further provided in the printing direction (right side).
To the empty discharge position KP on the empty discharge container 128,
A plurality of dots of ink droplets are discharged into the opening of the empty discharge container 128.

After the carriage 110 has passed the wiper 124, the eccentric cam 126 is further rotated to
And the wiper 124 is set in a retracted state. Thereafter, the carriage 110 moves to the printing surface 150 as it is if there is a print signal and performs a printing operation, and returns to the home position HP if there is no print signal. When the carriage reaches the home position HP, the cap 121 is advanced again to close the nozzle surface 112, and waits until a print signal comes.

The above operation is an operation for recovering the actual printing from being deteriorated due to entrainment of air bubbles or adhesion of dust to the recording head 111. However, usually, when good printing is performed, The above-described recovery operation involving suction is not performed. However, during printing, the ink in the nozzle holes that are not actually ejecting ink for printing gradually dries. Therefore, in order to maintain a favorable ejection operation, it is necessary to eject the ink before the ink in the nozzle hole where the ink is not ejected dries and to discharge the ink that is likely to be dried from the nozzle hole. Therefore, during printing, the carriage 110 is periodically moved to the empty ejection position KP, and ink droplets of a plurality of dots are ejected from all the nozzle holes to the opening of the empty ejection container 128 to prevent drying.

FIG. 3 is a sectional view of the empty discharge container when the empty discharge method of the present invention is employed. The carriage 110 is moved onto the empty discharge container 128, and the position of one end of the opening is defined as a first empty discharge position KP1. At that location, the recording head 111 ejects one dot of ink from each nozzle hole. And the carriage is KP1
Even if you come to, keep moving and keep moving. And carriage 1
When 10 moves from KP1 to the other end of the opening of the empty discharge container 128 by one dot (this position is referred to as a second empty discharge position KP2), the recording head 111 again applies one dot of ink from each nozzle hole. Discharge only. While moving the carriage 110 in this manner, the idle discharge position is slid one dot at a time from one end of the opening of the empty discharge container 128 to the other end, and one dot of ink is discharged from each nozzle hole at each idle discharge position. And a predetermined number of dots are ejected.

By adopting such a method, since the ink accumulation 300 does not form a stalagmite, it grows so as to come into contact with the recording head, which causes movement of the recording head, impairs print quality, or causes clogging of nozzles. And the reliability of the print recovery device 120 itself increases. In addition, since the ink accumulation 300 accumulates evenly from the bottom of the empty discharge container 128, there is no useless space in the container. Further, since the container can be expanded in the lateral direction, it becomes possible to cope with the design of a thin inkjet recording apparatus. In this example, the idle discharge positions are shifted by one dot. However, since the ink accumulation 300 accumulates on the hill, when designing a thinner inkjet recording apparatus, the idle discharge position is shifted by two to three dots. The same effect can be obtained even if the position is shifted and the vertical direction is reduced accordingly.

Here, the required width of the empty discharge container 128 is determined by the required number of empty discharge dots and the resolution of the head. When a pigment-based ink is used, the number of dots of ejected droplets required for one empty ejection operation is 10 to 20 dots. Therefore, if the head resolution is 120 DPI, in the above example, the empty ejection container 128 The required width of the opening is about 4.2 mm.

[0018]

According to the present invention, it is possible to obtain a small and reliable print recovery apparatus in which the ink accumulated in the empty discharge container does not form stalagmites.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a print recovery device of an ink jet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a print recovery device of the inkjet recording apparatus according to the embodiment of the present invention.

FIG. 3 is a sectional view of an empty discharge container showing ink accumulation in the case of the empty discharge method of the present invention.

FIG. 4 is a cross-sectional view of an empty discharge container showing ink accumulation in the case of a conventional empty discharge method.

[Explanation of symbols]

 HP carriage home position KP idle discharge position 110 carriage 111 recording head 112 nozzle surface 113 carriage shaft 114 cartridge holder 115 discharged ink droplet 120 print recovery device 121 cap 122 cap holder 123 suction tube 124 wiper 125 wiper holder 126 eccentric cam 127 camshaft 128 Empty discharge container 150 Printing surface 300 Ink accumulation

Claims (1)

[Claims] 1. A printhead for discharging a pigment-based ink from a discharge port, a carriage mounted with the printhead and moving, and an idle discharge having an opening for accommodating ink that has been idlely discharged from the printhead. In the ink jet recording apparatus having a container, while the carriage moves from the position of one end in the opening of the empty discharge container to the position of the other end in the opening, the ejection of the discharge is performed in conjunction with the movement of the carriage. An ink jet recording apparatus configured to perform idle discharge of ink by sliding a point.