JPH02175254A - Ink jet printer - Google Patents

Abstract

PURPOSE:To realize the function of a line printer of simultaneously conducting a printing for one line to enhance a printing speed by providing an ink jet head selectively discharging ink drips and n-pieces of deflecting means each of which deflects the flying path of the discharged ink drip to make it adhere on a printing medium over a width 1- or m-times larger than a printing dot gap. CONSTITUTION:A coil driver 23e generates a drive current to an electromagnet 15e on the basis of a pulse train supplied from a pulse train generation circuit 22 at a predetermined period and a printing request indicating binary signal supplied from a recording signal source 21e for every dot group for one character in a line direction, thereby conducting the attraction and release of a hammer 14e. On the other hand, a deflection voltage generation circuit 25 generates a sawtooth deflection voltage, which approximately linearly increases over the range corresponding to the dot number for one character and, thereafter, returns to an original value, and supplies the voltage to a deflecting electrode group 3. Then, an electrified ink drip is angularly deflected to come into collision with printing paper P. This ink liquid adheres to the collision position to form a dot required for printing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inkjet printer used as a data output device for computers and the like.

(Prior Art) Incendo printers are commonly used as data output devices for computers and the like.

A typical inkjet printer is an inkjet printer, as shown in Figure 4.

110 and a roller 50 for paper feeding. An ink discharge port 4] is formed at the tip of the inkjet head 40, and a piezoelectric element 43 is installed in a pressure chamber 42 that communicates with the ink discharge port, and an ink reservoir 42 is formed further behind the pressure chamber 42. ing. Piezoelectric element 43
Selective driving power is supplied from an electric circuit (not shown) depending on whether printing is necessary. The ink in the pressurizing chamber 42 that is displaced by the deflection of the selectively driven piezoelectric element 43 is ejected forward as ink droplets, flies through space, and adheres to the paper P.

In Fig. 4, main scanning in the line direction (direction perpendicular to the paper surface in the figure) is performed by sending an inkjet head with one ejection port one dot at a time in the direction perpendicular to the paper surface, or by moving the inkjet head in the direction perpendicular to the paper surface by one dot at a time, or This is done by sending a multi-nozzle inkjet head, which has a number of ejection ports equal to the number of dots for one character in the direction, in the line direction one character at a time.

Further, the sub-scanning in the column direction is performed by rotating the roller 50 and feeding the paper one dot at a time each time one line of stamps is completed.

(Problems to be Solved by the Invention) The conventional inkjet printer described above has a configuration in which the inkjet head is sent in the line direction one dot or one character at a time. For this reason, there is a problem that main scanning by feeding the head takes time, and high-speed printing cannot be performed.

If we create a head with the same number of ejection ports as the number of dots required to print one line, and use a line printer format in which ink droplets are ejected from all the ejection ports at once,
Printing speed can be improved since head feeding is no longer necessary. However, with conventional inkjet heads, a pressure mechanism such as a piezoelectric element is required for each dot or character, so the number of pressure mechanisms required to print one line is extremely large, making the device expensive. .

Furthermore, conventional pressurizing mechanisms, as typified by piezoelectric elements, have extremely low energy conversion efficiency.For this reason, even if a pressurizing mechanism for one line of supplies could be constructed, it would be difficult to operate them all at once. requires extremely large driving power and is not practical.

(Means for Solving the Problems) In the inkjet printer of the present invention, the distance between printing dots in a direction substantially perpendicular to the feeding direction of the print medium is approximately equal to m times the printing dot interval in this direction (m is a natural number of 2 or more). a plurality of ink ejection ports arranged at intervals, n ink chambers (n is a natural number of 2 or more) that hold ink to be supplied to each ink ejection port with partitions interposed between each other behind the ink ejection ports; n elastic sections formed behind and communicating with these ink chambers and corresponding elastic sections installed behind these elastic sections are selectively struck based on electromagnetic force selectively generated in accordance with recording signals. n tM
! An inkjet head having a hammer is installed between the inkjet head and the printing surface, and the ink droplets are deflected from each ink droplet by deflecting the flight path of the ink droplets ejected from each of the ink ejection ports. By providing n deflection means for depositing onto the print medium over a width from twice to m times, it is possible to eliminate the need to feed the head in the line direction and reduce the drive power required for pressurization. It is configured to realize the function of a line printer that prints one line at once.

Hereinafter, the operation of the present invention will be explained in detail together with examples.

(Embodiment) FIG. 1 is a partial perspective view showing a part of an inkjet printer according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views thereof.

This inkjet printer is composed of an inkjet head 1, a deflection section consisting of a charging electrode 2 and a deflection electrode 3, and a feed roller 4 for feeding paper.

The ink chambers 11 constituting the head 1 fixed on the base plate 10 are separated into a plurality of ink chambers 11a,
It is divided into llb, llc, etc. The ink filled in each ink chamber is supplied to ink ejection ports 12a, 12b, 12c, . . . formed at the tip of each ink chamber. These ink ejection ports 12a, 12b, 1
2c... are arranged in a line direction perpendicular to the direction in which the printing paper P is fed by the feed roller 4 at an interval that is 24 times the printing dot interval in the inward direction.

That is, these discharge ports 12a, 12b, 12c...
The arrangement interval in the line direction (generally referred to as the "ejection port group 12") corresponds to the line width of one character in a 24x24 dot configuration to be printed. Further, the total number of the ejection port groups 12 corresponds to the maximum number of characters in the line direction required for printing.

Ink chambers 11a, llb, 1lc-(r ink chamber group 11
4), there are stretchable elastic parts 13a, 13b, 13c made of rubber and communicating with the corresponding ink chambers.
... is formed. At the rear of each of the elastic partial groups 13 is a plate-shaped hammer 14 made of iron-based alloy or the like. a14b, 14C, . . . are installed, and behind each of the hammer group 14 is an electromagnet 15a.

15b, 15c... (electromagnet group 15) are installed. Further, although not shown in the drawings to avoid complication, an ink supply pipe is connected to the upper surface of each of the ink chamber groups 11 and connected to a common ink tank via a suitable backflow prevention valve.

As shown in FIGS. 2 and 3 representatively by the portion related to the ejection port 12e in FIG. 1, when printing one character in the line direction, a pulse train of a predetermined period is generated in the pulse train generation circuit 22. The coil driver 23e installed for each discharge port, the voltage amplification circuit 24 and the deflection voltage generation circuit 2 commonly installed in the discharge port group 12
5. The coil driver 23e receives the pulse train of a predetermined period supplied from the pulse train generation circuit 22 and the recording signal source 21g for each character's worth of dots in the line direction.
The hammer 14e is attracted (FIG. 2) and released (FIG. 3) by generating a selective drive current to the electromagnet 15e based on a binary signal that instructs whether printing is necessary or not, supplied from the electromagnet 15e. .

On the other hand, the deflection voltage generating circuit 25 generates a sawtooth wave deflection voltage that increases almost linearly over the number of dots corresponding to one character and then returns to the original value, and generates a sawtooth wave deflection voltage that increases the number of dots corresponding to one character and then returns to the original value. supply to.

When a drive current is supplied to the coil of the electromagnet 15e,
The hammer 14e is attracted to the electromagnet 15e against the restoring force based on its elastic deformation. When the hammer 14e is sucked, the elastic portion 13e expands backward, and the pressure inside the ink chamber lle accordingly decreases, and ink is supplied into the ink chamber 116 from an upper ink tank (not shown) via an ink supply pipe. (Figure 2). After this, when the supply of drive current to the electromagnet 15e is interrupted, the hammer 15e, which has been attracted to the electromagnet 15e, returns to its original state due to its elastic restoring force and strikes the elastic portion 13e.

The volume of the elastic portion 13e is reduced by this impact by the hammer 15e, and the displaced ink in the ink chamber 11e is ejected in front of the ejection port 12e (FIG. 3).

The ink droplets ejected from the ejection ports 12e are charged by charging electrodes 2 which are disposed across the flight path of the ink droplets and which perform discharge upon receiving high voltage pulses from the voltage amplification circuit 24. This charged ink droplet is transferred to a deflection voltage generating circuit 25.
The beam is deflected at an angle approximately proportional to the voltage value of the deflection electrode 3e which receives a sawtooth wave deflection voltage from the beam, and collides with the printing paper P along a flight path as shown by the dotted line in FIGS. 2 and 3. The ink droplets adhere to the point of impact and form the dots necessary for printing.

Ink droplets are ejected from the ink ejection port group 12 only from the ejection ports necessary for printing.

Therefore, when all characters to be printed are present on one line of paper, ink is ejected from all the ejection ports at the same time. In addition, the maximum number of strikes required by the electromagnetic hammer to print one line of one character is the number of hits equivalent to the number of dots for one character in the line direction (in this example, the maximum number of hits is 2.
4 times).

When printing for 1947 minutes is completed in this way, the printing paper P is fed in the vertical direction by an amount corresponding to the width of one dot based on the rotation of the feed roller 4, and then printing for one line is repeated. Further, when printing of the final line of the character ``■'' is completed, the printing paper P is fed by an amount corresponding to the width of one line by the rotation of the feed roller 4, and printing of a new line in line units is started.

The configuration of a line printer that simultaneously prints 1947 minutes has been exemplified above. However, if a larger line width is required, an appropriate number of inkjet printers, such as two or three, may be installed in the line direction to compensate for the required width of one line. . This configuration also achieves the effects of the present invention in that it is not necessary to feed the head, and the drive power can be reduced because the pressurizing efficiency is high.

In addition, one ink droplet ejected from one ejection port
Although a configuration in which printing is performed for characters is illustrated, a configuration in which printing is performed for an appropriate number of characters, such as a plurality of characters or half a character, may also be used.

Furthermore, a configuration has been illustrated in which the deflection mechanism in the line direction installed between the inkjet head and the printing surface is realized by a combination of a charging electrode and an electrical deflection electrode. However, as such an ink droplet deflection mechanism, there are various known methods, or as disclosed in the specification of the applicant's earlier application, a charging mechanism and a selective light irradiation to the photoconductive layer are used. Any suitable method can be applied, such as a method in combination with an electric field deflection mechanism that utilizes charge movement, or a method in combination with magnetic ink and selective magnetic field deflection means.

<Effects of the Invention> As explained in detail above, the inkjet printer of the present invention
The printer is an inkjet printer that selectively ejects ink droplets from the ones necessary for printing out of n ink ejection ports arranged at intervals approximately equal to m times the printing dot spacing on the line ark by striking an electromagnetic hammer. The ink droplet is configured to include a head and n deflection means that deflect the flight path of the ejected ink droplets to deposit the ink droplets on the print medium over a width ranging from 1 to m times the printing dot interval. Therefore, there is no need to move the head in the line direction, and drive power is reduced due to improved pressurizing efficiency.

As a result, it is possible to achieve the function of a line printer that preferably prints 1947 minutes at the same time, and it is possible to achieve the effect that the printing speed can be improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of an inkjet printer according to an embodiment of the present invention, FIGS. 2 and 3 are sectional views of the inkjet printer, and FIG. 4 is a diagram showing a typical conventional inkjet printer. FIG. 3 is a sectional view showing the configuration. 1... Inkjet head, 2... Charging electrode,
3... Deflection electrode, 4... Feed roller 11... Group of N ink chambers formed along the line direction, 12...
Ejection port group, 13... Elastic portion group at the rear of the ink chamber, 14
...Hammer group that strikes the corresponding elastic subgroup, 15...
- Electromagnet group, 2■... Recording signal source, 22... Pulse train generation circuit, 23e... Coil driver, 24...
Voltage amplification circuit, 25... Deflection voltage generation circuit. Patent applicant: NEC Home Electronics Co., Ltd.

Claims (4)

[Claims] (1) n dots (n is a natural number of 2 or more) arranged in a direction substantially perpendicular to the feeding direction of the print medium at an interval approximately equal to m times the printing dot interval in this orthogonal direction (m is a natural number of 2 or more) ) ink discharge ports, n ink chambers that hold ink to be supplied to each ink discharge port with partitions interposed between them behind these ink discharge ports, and an ink chamber formed at the rear of and communicating with these ink chambers. an inkjet head having n elastic parts and n electromagnetic hammers installed behind these elastic parts and selectively hitting the corresponding elastic parts based on electromagnetic force selectively generated in accordance with a recording signal; , is installed between the inkjet head and the printing surface, and deflects the flight path of the ink droplets ejected from each of the ink ejection ports so that the ink droplets are spread from 1 to m times the printing dot spacing. an inkjet printer comprising: n deflecting means for depositing onto the printing medium across its width. (2) The n ejection ports are formed over the width of one line on the printing medium, and printing for one line is performed at the same time by ejecting and deflecting ink droplets from the necessary ones at the same time. An inkjet printer according to claim 1, characterized in that: (3) The n ejection ports are formed over a width that is an integer fraction of the width of one line on the printing medium, and the ink droplets that are ejected and deflected at the same time from the necessary ones among them are formed to cover this integer number of ejection ports. 2. The inkjet printer according to claim 1, wherein printing is performed simultaneously over one width of the inkjet printer. (4) The n deflecting means include a charging mechanism that charges the ink droplets ejected from each of the ejection ports, and n voltage deflectors that deflect the charged ink droplets with a monotonically increasing or decreasing voltage. An inkjet printer according to any one of claims 1 to 3, characterized in that it is comprised of a mechanism.