JPH0316738A - Ink tank in ink jet printer - Google Patents

Abstract

PURPOSE:To stably conduct a high quality printing by providing an ink refilling port provided with a valve mechanism to be opened only at the time of refilling an ink and a leak valve to make an inner pressure releasable to atmosphere under electrical control. CONSTITUTION:In a normal state that a valve is closed, a seal material 31 is pressed on the top surface of an ink tank 1 by a restoring force of a valve spring 34. At the time of refilling an ink, an ink cartridge is pressed against a cartridge receiving port 32, and the valve of an ink refilling port 3 is opened. In this state, the valve spring 34 is compressed by a pressing force to the ink cartridge, an ink flow path 33 is connected to the inside of the ink tank 1, and the ink flows into the ink tank 1. An electromagnetic valve 43 provided on an atmosphere release port 41 is electrically conducted to be opened at an ink refilling time and a printing time or a purging time. In this manner, a printing can be applied with an invariably stable quality while a pressure inside the ink tank at the time of printing is invariantly kept equal to an atmospheric pressure, an unwanted pressure fluctuation is never transmitted to a printing head, and the evaporation of an ink is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink tank, which is an ink storage section in front of an inkjet printer head, and particularly relates to a mechanism for alleviating pressure fluctuations inside the ink tank and suppressing changes in the substance of the ink. Regarding. [Prior Art] Conventionally, this type of ink tank of an inkjet printer has a simple lid on the ink replenishment port to prevent ink from evaporating, and a leak hole for opening to the atmosphere to prevent negative pressure from forming inside the ink tank. Was. In some cases, a bag sealed with a thin film such as polyethylene was used as an ink tank to prevent evaporation and to keep the pressure inside the bag always equal to atmospheric pressure. [Problems to be Solved by the Invention] In the ink tank of the conventional inkjet printer described above, it is difficult to satisfy the two requirements of suppressing ink evaporation and maintaining the pressure inside the tank at atmospheric pressure. there were. Furthermore, even when polyethylene bags were used to solve this problem, negative pressure could be generated inside due to the bag's elasticity. As a result, if the ink evaporates to some extent, the viscosity of the ink itself increases, to varying degrees, and even if you try to eject ink droplets from the head under the same driving conditions as before, the ink droplet diameter will decrease. This has the disadvantage that the printing quality may change or the flying speed of ink droplets may decrease, leading to a decline in print quality and, ultimately, ink droplets becoming unable to be ejected. Furthermore, if negative pressure is generated inside the ink tank, ink cannot be properly supplied from the ink tank to the print head, which deteriorates the frequency followability of ink droplet jetting, resulting in the ink droplet jetting becoming impossible. [Means for Solving the Problems] The ink tank of the inkjet printer of the present invention has an ink refill port equipped with a valve mechanism that opens only when ink is refilled, and an electrically controlled ink tank that allows internal pressure to be released to the atmosphere. It has a leak valve. [Example] Next, the present invention will be explained with reference to the drawings. FIG. 1 is a schematic diagram of an embodiment of the present invention. An ink supply pipe 2, an ink replenishment port 3 on the ink tank 1. An atmosphere opening 41 is provided, and the ink 5 in the ink tank is guided through the ink supply pipe 2 to a print head not shown in the figure. Figure 2 explains the valve mechanism of the ink refill port 3, where (a) shows the normal valve closed state, and (b) shows the ink cartridge 6 pressed against the cartridge socket 32 when refilling ink. indicates that the ink refill port valve is open. In the state of (a), the restoring force of the valve spring 34 presses the sealing material 31 against the top surface of the ink tank 1, the ink flow path 33 is not connected to the inside of the ink tank 1, and the ink refill port 3 is closed. In the state of (b), the valve spring 34 is compressed by the force pressing the ink cartridge 6, and the ink flow path 33 is connected to the inside of the ink tank l. At this time, the ink in the ink cartridge 6 is transferred to the cartridge socket 3.
2 flows into the ink tank 1 through the ink flow path 33. The opening and closing of the electromagnetic valve 43 provided on the atmosphere opening 41 is controlled by electric signals, but it is energized and opened only during the above-mentioned ink replenishment, printing, or purging. [Effects of the Invention] As explained above, the present invention provides an atmosphere opening port on the ink tank that can be controlled to open and close, and an ink replenishment port that is opened only when replenishing ink. The internal pressure is always maintained at atmospheric pressure, eliminating unnecessary pressure fluctuations from being transmitted to the print head, and preventing ink evaporation during long periods of non-use or transportation, minimizing changes in the physical properties of the ink, making it always stable. This has the effect of allowing you to obtain high-quality printing.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view schematically showing an ink tank of an inkjet printer according to an embodiment of the present invention, and FIG.
) and (b) are cross-sectional views illustrating the valve mechanism of the ink replenishment port in FIG. 1. 1... Ink tank, 2...
...Ink supply pipe, 3...Ink refill port, 5...
・Ink, 6... Ink cartridge, 31... Seal material, 32... Ink cartridge socket, 33...
・Ink channel, 34... Valve spring, 41...
- Atmospheric release port, 42... Atmospheric release port, 43... Solenoid valve.

Claims (1)

[Claims] It is characterized by having an ink replenishment port equipped with a valve mechanism that opens only when ink is refilled, a leak valve for allowing internal pressure to be released to the atmosphere, and means for electrically controlling the leak valve. An ink tank for an inkjet printer.