JPH1120180A - Mechanism for adjusting pressure of ink tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holding part structure restricting a pressure change of an ink tank at the time of printing to a minimum and optionally change to a suitable pressure, by mechanically moving up and down a holding part for the ink tank and changing a water head value. SOLUTION: In a normal print state, an ink tank 20 is set at a most suitable height to a height of a nozzle plate 10a, namely, at a height achieving a most suitable pressure. The height is set by a remaining ink amount detection spring 31, and an optional height-setting mechanism 32 is in a free state. A constant of the spring linking to a weight of ink functions to raise a tank holder 30 by the amount of the pressure reduced when the ink decreases, thereby setting an optimum pressure at all times. Accordingly, printing is carried out under a constant pressure at all times before the ink tank becomes empty after the ink tank is full, with an allowance given to a range where performed is fulfilled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a structure of a holding portion of an ink tank which is an ink supply source of an on-demand type ink jet printer.

[0002]

2. Description of the Related Art A conventional ink tank, whether a carriage mounted type or a printer body stationary type, does not have a structure in which it is physically raised or lowered, but is fixed at a certain height.

[0003]

However, when the ink tank is fixed at a certain height, it is inevitable that the pressure in the ink tank fluctuates so as to increase toward the negative pressure side as the amount of ink decreases. Since this fluctuation in pressure greatly affects the ink ejection performance of the head, various techniques and restrictions are required to be satisfied in the entire fluctuation range.

[0004] In particular, in order to increase the capacity of the ink tank, this pressure fluctuation also increases, which is important as a technical problem.

When cleaning the head, if the pressure inside the ink tank is a negative pressure, it is difficult to remove bubbles and foreign matters around the nozzles, and bubbles are generated due to instantaneous pressure fluctuations when the ink is released after suction. It interferes with normal meniscus formation.

SUMMARY OF THE INVENTION In order to solve this problem, an object of the present invention is to provide a structure of an ink tank holding section for minimizing the pressure fluctuation of an ink tank during printing, and to arbitrarily change the pressure to an appropriate pressure according to the situation at that time. An object of the present invention is to provide a structure of an ink tank holding section to be made to work.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for controlling the pressure of an ink tank with respect to a head based on a change in a water head value of a holding portion of an ink tank. Can be set to. This makes it possible to raise the ink tank according to the amount of ink depletion during printing and to keep the pressure constant at all times.Also, when cleaning the head, set the pressure to a value suitable for the content of the cleaning, and ensure a short time. It is now possible to clean.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall system diagram showing the relationship between the print head and the ink tank. Print head 10
Is provided with a nozzle plate 10a, and the ink tank 20 is set at a certain height based on the height thereof. The ink tank 20 is usually fixed to a tank holder 30 and supplies ink to the head via an ink supply tube 40. The tank holder 30 is provided with an arbitrary height setting mechanism 32 that can arbitrarily move the tank holder 30 up and down, and is also connected to the ink remaining amount adjusting spring 31 in a normal printing state.

Next, the operation in a normal printing state will be described. The normal printing state is basically the state shown in FIG. At this point, the height of the ink tank 20 is set to be the most appropriate height, that is, the most appropriate pressure, with respect to the height of the nozzle plate 10a. This height is a height set by the ink remaining amount detecting spring 31, and the arbitrary height setting mechanism 32 is in a released state. This spring constant is linked to the weight of the ink, and functions to raise the tank holder 30 by an amount corresponding to the pressure at which the ink is lost and lost, so that the optimum pressure is always set. As a result, printing can be performed under a constant pressure from the time when the ink tank is full to the time when the ink tank becomes empty, thereby giving a margin to the range where performance is established.

At this time, if a window is opened so that the ink tank 20 or the tank holder 30 can be seen on the exterior part of the printer and a scale is provided, the remaining amount detection mechanism is used as it is.

Next, the operation of cleaning the head will be described with reference to FIG. For example, when it is desired to suck air bubbles or dust in the nozzle, the tank holder is raised by the optional height setting mechanism 32 so that the pressure of the ink is set to the atmospheric pressure or higher, so that the ink can flow easily. , It is possible to perform cleaning with a small suction force and in a short time. Further, if the height is adjusted so that the ink pressure becomes the atmospheric pressure after the stop of the suction, instantaneous pressure fluctuation does not occur even when the suction cap 60 is separated from the nozzle plate 10a, and the normal meniscus is reliably applied to the nozzle. It is formed. Therefore, it is not necessary to provide a special pressure adjusting valve or the like on the suction cap 60.

Further, if a pressure sensor is set in the ink supply tube, all of the above-mentioned explanations can be controlled by software, and the reliability can be improved.

[0013]

The present invention is an effective means for realizing an ink jet printer system and improving the reliability by minimizing factors of pressure fluctuation as much as possible.

[Brief description of the drawings]

FIG. 1 is an overall view of an inkjet printer system.

FIG. 2 is an overall view showing an operation at the time of head cleaning.

Claims (2)

[Claims] 1. An ink tank, which is an ink supply source of an ink-jet printer, characterized in that the ink tank has a mechanism for physically moving up and down according to conditions such as printing and head cleaning. Structure of tank holding part. 2. The structure of an ink jet printer having a mechanism capable of detecting a remaining amount of ink in an ink tank from a physical height of the ink tank.