JPH04263956A - Printing head for ink jet printer and control thereof - Google Patents

Abstract

PURPOSE:To increase a printing speed, to prevent operation inferiority and to increase a jet ink speed by providing a plurality of ink jet mechanisms to an ink flow passage and controlling the operation timings thereof. CONSTITUTION:When an ink jet printing head and the driving system thereof are driven, an ink cavity is forcibly replenished with ink by an ink replenishing mechanism l-2 after or immediately before the injection of ink due to an ink jet mechanism 1-1 is completed. Therefore, the ink replenishing speed to the ink cavity increases and a printing speed is increased. The force acting on the ink in the ink flow passage before and after the ink cavity becomes the direction injecting the ink from a nozzle 1-4 and the recession of an ink meniscus or the suction of air immediately after injection and the back flow of the ink are prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head mechanism for inkjet printers and plotters that print by jetting liquid ink from nozzles.

0002

2. Description of the Related Art FIG. 2 shows the shape of a print head of a conventional inkjet printer or plotter. Conventionally, the ink ejection mechanism that existed in the ink flow path was one stage for each printing nozzle, and was used only to eject ink from the nozzle, and the ink transport method to the nozzle tip was based on the capillary phenomenon of the fluid ink, pressure balance, etc. I rely on it.

0003

[Problems to be Solved by the Invention] In the conventional system, the replenishment of ink into the ink cavity after ink ejection depends on a natural phenomenon caused by the pressure difference in the ink flow path before and after the ink cavity, and the heating resistor that is the ink ejection mechanism The ink replenishment speed could not keep up with the possible drive speed of the body and piezo transducer, and the printing speed inevitably decreased.

Furthermore, in the conventional method, the replenishment of ink into the ink cavity after ink ejection depends on a natural phenomenon caused by the pressure difference in the ink flow path before and after the ink cavity. The flow path must be set, and if the balance is lost, air may be drawn in from the nozzle, or the cavity may not be fully refilled, resulting in poor printing performance.

[0005] Therefore, the present invention improves the printing speed and eliminates printing malfunctions by forcibly replenishing ink into the ink cavity in order to solve the conventional printing speed decrease and printing defects caused by such effects. The purpose is to

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a similar system upstream of the ink jetting mechanism, which conventionally had only one for jetting ink from a nozzle in one ink flow path. Alternatively, one stage or several stages of ink jetting mechanisms of different types are provided, and corresponding control mechanisms are provided for each of them to form an ink jetting mechanism and an ink replenishment mechanism, each with a delay to enable interlocking control.

[0007]

[Operation] When the inkjet print head configured as described above and its drive method are driven, the ink replenishment mechanism forcibly replenishes ink into the ink cavity at or just before the end of ink jetting by the ink jetting mechanism. I do. Therefore, the speed at which ink is replenished into the ink cavity increases, and the printing speed can be improved. In addition, the force acting on the ink in the ink flow path before and after the ink cavity is only in the direction of ejecting the ink from the nozzle, which prevents the ink meniscus from receding immediately after ejection, air suction, and ink backflow, reducing printing malfunctions.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. Figure 1 shows an example of a two-stage jetting system in which the ink jetting mechanism uses a bubble jet system using a heating resistor (1-1), and the ink replenishing mechanism uses a Kaiser system using a piezo transducer (1-2). It is. Ink is supplied from the ink reservoir 1-3 to the ink jet nozzle 1-4.
is sprayed from. The ink ejection mechanism is selectively energized based on the print data and fixes the print pattern on the print medium, whereas the ink replenishment mechanism is unrelated to the print data and takes timing with the energization of the ink ejection mechanism. By setting the arrangement position to a common ink reservoir, the number of ink ejecting mechanisms may be smaller than the number of ink ejecting mechanisms.

FIG. 3 is an actual diagram showing the ink ejection mechanism, ink supply mechanism, and ink operation timing in this embodiment. In the initial state (FIG. 3(A)), the ink is filled up to the nozzle and is stable. When the heating resistor is energized, Figure 3 (
As shown in B), bubbles are generated and ink is ejected from the nozzle. Thereafter, as shown in FIG. 3C, when the bubbles begin to shrink, the piezo transducer of the ink supply mechanism is energized, and ink is forcibly replenished. Therefore, the time required to return from the state shown in FIG. 3(C) to the state shown in FIG. 3(A) is shortened, and the printing speed is improved. Further, during this process, the ink does not flow backwards, so air bubbles are not sucked from the nozzle, so stable operation can be achieved.

FIG. 4 is a diagram showing an embodiment in which the ink supply mechanism is further provided with one more stage of ejection mechanism.
1 and the ink supply mechanism 4-2 operate in the same manner as in the embodiment shown in FIG. However, it becomes possible to increase the speed of ink ejection from the nozzle and improve the ejection distance.

[0011]

As described above, the present invention has the effect of increasing the printing speed and preventing malfunctions by providing a plurality of ink ejecting mechanisms in the ink flow path and controlling their operation timings. It is also possible to obtain additional effects such as increasing the ejected ink velocity.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment in which ink ejection mechanisms are provided in two stages.

FIG. 2 is an explanatory diagram showing the shape of a conventional print head.

FIG. 3 is an actual diagram showing the operation of the two-stage injection mechanism.

FIG. 4 is a diagram showing an embodiment in which ink ejection mechanisms are provided in three stages.

[Explanation of symbols]

1-1 Ink ejection mechanism of heating resistor 1-2, 4-2
, 4-3 Piezo ink supply mechanism 1-3 Ink reservoir 1-4 Ink jet nozzle

Claims (2)

[Claims] [Claim 1] Liquid ink is ejected from a printing nozzle,
An inkjet printhead characterized by having a plurality of ejection mechanisms and their drive circuits as an ink ejection device, in serial and line printheads for inkjet printers and plotters that fix prints on print media such as paper and produce print output. 2. One of the plurality of ink ejection mechanisms operates to eject ink from a nozzle, and the remaining ink ejection mechanisms operate to forcibly replenish ink into an ink cavity after ink is ejected by the one ejection mechanism. A print head control method characterized by controlling operation timing.