JPH09164707A - printer - Google Patents

Abstract

(57) Abstract: To provide a printer in which a landing position on a printer paper is a planned position even when a concentration of a coloring liquid changes. A storage unit (RO) is provided with a control circuit 13 for controlling a printing (printing) mechanism 8 including a head 1, and the control circuit 13 stores time correction data according to the concentration of a coloring liquid.
M) 16a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier jet printer for printing by mixing a coloring liquid and a diluting liquid.

[0002]

2. Description of the Related Art An on-demand type ink jet printer is a printer which ejects ink droplets from a nozzle in response to a recording signal to record it on a recording medium such as paper or film, and can be downsized and reduced in cost. Therefore, it has been rapidly spreading in recent years. On the other hand, in particular, in the office, document creation using a computer called desktop publishing has become popular, and recently it is said that not only letters and figures but also natural images like photographs are output together with letters and figures. The demand is increasing. To print a high-quality natural image, it is important to reproduce halftones.

Although various methods have been proposed for ejecting ink droplets, a method using a piezo element or
A method is known in which ink is heated and boiled by a heating element, and the ink is ejected by the pressure of bubbles generated.

Various methods have been proposed for reproducing halftones. As a first method, there is a method in which the voltage applied to a piezo element or a heating element or the pulse width is changed to control the size of a droplet to be ejected so that the diameter of a print dot is made variable to express gradation. However, in the first method, if the voltage or pulse width applied to the piezo element or the heating element is excessively reduced, ink is not ejected, so that the minimum droplet diameter is limited, and the number of gradation steps that can be expressed is small, and particularly low density. There is a drawback that it becomes impossible to express. Therefore, it is very unsatisfactory to print out a natural image.

As a second method, there is a method in which one pixel is formed by a matrix of, for example, 4 × 4 dots without changing the dot diameter, and gradation is expressed in units of this matrix by using a so-called dither method. . However, even in the second method, when one pixel is formed by a 4 × 4 matrix, for example, a density of 17 gradations can be expressed. For example, the same dot density as that in the first method is used for printing. In this case, the resolution is reduced to 1/4 and the roughness is conspicuous, which is also unsatisfactory for printing a natural image.

In order to overcome the above-mentioned drawbacks of the conventional method, the present applicant has filed Japanese Patent Application No. 6-6282714.
In Japanese Patent Application No. 7-75377, a so-called on-demand type carrier jet printer makes it possible to control the density of ink of ejected droplets, that is, the density of printed dots, resulting in deterioration of resolution. We have proposed a carrier-type printer that can print natural images without requiring them to do so.

However, in this type of carrier jet printer, when the colored liquids are mixed, the flight direction of the mixed droplets is bent, and the problem that the droplets land on the printer paper is displaced occurs. As a result, the printing or printing quality is degraded. In particular, at the change point of the density of the gradation image, the positional deviation of the dots is noticeable.

The phenomenon in which the mixed droplet is bent in the flight direction will be described with reference to FIGS.
Is a front view of a printer head used in the present invention,
FIG. 6 is a plan view of an ink dot showing a liquid deposition position of the mixed droplet on the printer paper, and FIG. 7 is a state of the liquid until the mixed droplet is ejected. FIG.

As shown in FIGS. 5 and 7 (a), the head 1 is composed of a rectangular parallelepiped body 1a made of stainless steel or the like, and has a discharge nozzle 2 and a metering nozzle 3 therein. The discharge nozzle 2 has a carrier liquid 4 at one end of the body 1a.
Is provided with a supply port 2a and a discharge port 2b at the other end, and a first piezo element 2c for pushing out the carrier liquid 4 is provided at the center thereof.

The metering nozzle 3 is provided with a supply port 3a for the coloring liquid 5 at one end of the body 1a and an ejection port 3b adjacent to the ejection port 2b for the carrier liquid 4 at the other end, and to push out the coloring liquid 5 at the center thereof. Discharge port 2 provided with the second piezo element 3c
As shown in FIG. 5, b and 3b are arranged in a row so that the metering nozzles 3 are located in the head scanning direction HD, and a plurality of pairs of these ejection openings 2b and 3b are arranged in parallel.

FIG. 7A shows a state before ejection, and when the first piezo element 2c and the second piezo element 3c are driven from this state, the carrier liquid 4 and the coloring liquid are ejected from the ejection ports 2c and 3c. 5 is slightly discharged, and the discharge port 2 is discharged as shown in FIG.
Wetting 6 occurs between c and 3c. This wetting 6 becomes a mixed liquid of the carrier liquid 4 and the coloring liquid 5, and as shown in FIG. 7C, when the carrier liquid 4 is further pushed out, a mixed liquid lump 7a is formed at the tip thereof, Next, as shown in FIG. 7D, mixed droplets 7b are formed and ejected toward the print paper.

In the course of developing this type of head, the inventors of the present invention recognized a phenomenon in which the landing position was not constant when the coloring liquid was mixed. As shown in FIG. 7D, it was confirmed that the colored mixed droplet 7b was warped in the direction closer to the discharge port 2 of the metering nozzle 3 than the originally intended discharge direction f1.
As a result, as shown in FIG. 6A, the position where the ink dots come in contact with the liquid is a position where the coloring position S2 when the coloring liquid is mixed is displaced from the coloring position S1 when the coloring liquid is not mixed by δ1.

This phenomenon is considered to be due to the surface tension of the colored liquid and the wetting of the metering nozzle side near the discharge port. Then, when the density of the coloring liquid is high, this deviation becomes remarkable, that is, the deviation amount δ2 when the density is high as shown in FIG. 6B is the deviation when the density is low as shown in FIG. 6C. It becomes larger than the quantity δ3. In the case of this conventional example, when the concentration of the coloring liquid is high, the mixed droplet 7b is ejected later than the original liquid ejection timing.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printer in which the landing position on the printer paper is a predetermined position even when the concentration of the coloring liquid changes.

[0015]

In order to solve such a problem, the printer according to the invention of claim 1 is provided with a means for correcting a deviation occurring at a landing position on a printing paper depending on a concentration of a coloring liquid. , It is possible to print accurately at the planned landing position. Here, the means for correcting the deviation that occurs in the liquid deposition position on the print paper means a superordinate concept of the ROM and the timing control circuit included in the control circuit of the printing mechanism.

A printer according to a second aspect of the present invention has the configuration of the printer according to the first aspect, which includes a coloring liquid discharge port and a head in which the carrier liquid discharge ports are vertically aligned in the print scanning direction. The position can be printed exactly at the planned position.

In the printer according to the third aspect of the present invention, the means for correcting the deviation at the landing position comprises means for advancing or delaying the ejection timing of the coloring liquid and the carrier liquid according to the concentration of the coloring liquid. With the configuration of the printer according to the item 1, it is possible to perform printing accurately at a predetermined liquid deposition position. Here, the means for advancing or delaying the ejection timing of the coloring liquid and the carrier liquid according to the concentration of the coloring liquid means a superordinate concept of the ROM and the timing control circuit.

A printer according to a fourth aspect of the present invention includes a control circuit for controlling a print mechanism including a head, and the control circuit includes storage means for storing time correction data corresponding to the concentration of the coloring liquid. With the configuration of the printer described above, it is possible to print accurately at the planned landing position. Here, the storage means that stores the time correction data corresponding to the concentration of the coloring liquid means a concept higher than the ROM and the timing control circuit.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic view of the entire apparatus including a control circuit block of a printer according to the present invention, and FIG. 2 is a timing chart of droplet discharge of the printer according to the present invention.
FIG. 3 is a discharge timing chart in which the droplets of the printer according to the present invention are corrected, and FIG. 4 is a graph showing the deviation of the concentration of the coloring liquid and the landing position.

In the embodiment of the present invention, the head 1 as shown in FIG. 5, that is, the head 1 in which the ejection port 3b of the metering nozzle 3 and the ejection port 2b of the carrier liquid 4 are arranged along the head scanning direction HD. In order to correct the deviation of the landing position on the printer paper, which changes depending on the concentration of the colored liquid 5, the printer using the method described above may stagger the discharge timing of the colored liquid 5 and the carrier liquid 4 as shown in FIG. Use as a summary.

That is, from the original discharge timing t1, β1
(Μs), and discharge is performed at the corrected discharge timing tc1. However, if the scanning direction of the head or the arrangement of the metering nozzle and the carrier liquid ejecting nozzle is different from that shown in FIG. 5, it is delayed.

Then, data obtained by experiments on the relationship between the concentration of the coloring liquid and the deviation of the landing position on the printer paper is prepared. In the present embodiment, as shown in FIG. 4, a curve in which the deviation of the landing position gradually increases according to the concentration was obtained.

Therefore, this data is stored in the ROM (Read
It is possible to write in the Only Memory), incorporate it in the control circuit of the printer, correct the ejection timing from the head, and print at the planned landing position.

R in which the correction data of the landing position is written
A printer in which the OM is incorporated in the control circuit will be described with reference to FIG. The printing (printing) mechanism 8 includes a driving drum 9a driven by a motor, a driving drum 9a, and a belt 9
The feed screw 1 of the head 1 that is provided horizontally with the drum 9c connected to the drum 9c facing the side surface of the drum 9c.
0 is provided. A carriage 11 screwed onto the feed screw 10 is provided, and the head 1 is mounted on the carriage 11. The print paper 12 is attached to the surface of the drum 9c. Then, during the printing operation, the print paper 12 is sequentially fed from the bottom to the top by the drum 9c, and the carriage 11
Is sent to the feed screw 10, the head 1 is moved from left to right, and printing (or printing) is performed.

The printing (printing) mechanism 8 has a control circuit 13
Is connected. The control circuit 13 includes an input circuit 14 to which print data is supplied and a microprocessor connected to the input circuit 14, and is a signal for discriminating the print mechanism control signal, print data, print timing control signal, etc. from the print data. A processing control circuit 15 and a timing control circuit 16 which is connected to the signal processing control circuit 15 and outputs a timing signal for printing are provided.

The timing control circuit 16 is provided with a ROM 16a that stores a correction value for correcting the above-mentioned droplet ejection timing in accordance with the concentration of the colored liquid. Further, the ink constant quantity drivers 17a and 17b are connected to the subsequent stage of the timing control circuit 16, and the ink constant quantity drivers 17a and 17b are connected to the head 1.
Connected to the first piezo element 2c and the second piezo element 3c, the carrier liquid 4 and the coloring liquid 5 are ejected from the ejection ports 2b, 3b at a predetermined timing.

A density data supply circuit 18 is connected to the input circuit 14, and the timing control circuit 1 is provided at the subsequent stage.
6, the ink constant quantity driver 17a is connected, and the coloring liquid 5
The liquid ejection timing is corrected in accordance with the concentration of, and a mixed droplet of a predetermined concentration is ejected from the nozzle of the head 1.

The signal processing control circuit 15 supplies control signals to the driving motor of the driving drum 9a and the actuator of the feed screw 10 to drive the mechanism for printing. Since the control circuit 13 can have various configurations as necessary,
The present invention is not limited to this embodiment.

FIG. 2 shows the timing of droplet ejection when a printing (printing) operation is performed using this printer.
The graph (A) shows the discharge timing of the colored liquid, and the graph (B) shows the discharge timing of the carrier liquid. The amplitude of each pulse in FIG. 2 is variable according to the density data. When the density is high, the amplitude is large, and when the density is low, the amplitude is small.

T1, t2, t3, and t4 are ejection timings without correction, tb1, tb3, and tb4 are corrected color liquid ejection timings, and tc1, tc3, and tc4 are corrected carrier liquid ejection timings. Between the timing of ejecting the color liquid and the timing of ejecting the carrier liquid, the color liquid ejection timing is set to α (μs) regardless of correction.
The fixed advance time of is given. As a result, at the ejection timing t1, the advance time of both liquids is corrected from the original ejection timing by the correction time β1, β3 at t3, and β4 at t4.

In the present embodiment, the white liquid is emitted at the timing t2, and the carrier liquid is ejected, but it is also possible not to eject both liquids. Further, when the arrangement of the carrier liquid ejection port and the color liquid ejection port is opposite to that of the present embodiment, the correction may delay the ejection timing.

[0033]

According to the present invention, it is possible to perform accurate printing with a simple structure and without deviation of the landing positions of mixed droplets, and in particular, there is no positional deviation of print dots at a conspicuous change point in density. The print quality can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of an entire apparatus including a control circuit block of a printer according to the present invention.

FIG. 2 is a timing diagram of droplet ejection of the printer according to the invention.

FIG. 3 is a discharge timing chart of corrected droplets of the printer according to the present invention.

FIG. 4 is a graph showing the deviation of the concentration of the colored liquid and the landing position.

FIG. 5 is a front view of the head of the printer used in the present invention.

FIG. 6 is a plan view of an ink dot showing a liquid landing position of a mixed droplet on a printer paper, (a) showing a deviation of the liquid landing position,
(B) When the concentration of the coloring liquid is high, (c) When the concentration of the coloring liquid is low.

7A and 7B are cross-sectional views of the nozzle of FIG. 5 taken along the line AA showing the respective states of the liquid until the mixed liquid droplets are ejected, where FIG. 7A is a state before ejection and FIG. A state in which the carrier liquid and the coloring liquid are slightly discharged, (c) is a state in which a mixed liquid lump is formed, and (d) is a state in which mixed droplets are discharged in the direction of the print paper.

[Explanation of symbols]

 1 Head 1a Body 2 Discharge Nozzle 2a Supply Port 2b Discharge Port 2c First Piezo Element 3 Quantitative Nozzle 3a Supply Port 3b Discharge Port 3c Second Piezo Element 4 Carrier Liquid 5 Colored Liquid 6 Wet 7a Mixed Liquid Clot 7b Mixed Droplet 8 Printing (printing) mechanism 9a Drive drum 9b Belt 9c Drum 10 Feed screw 11 Carriage 12 Printed paper 13 Control circuit 14 Input circuit 15 Signal processing control circuit 16 Timing control circuit 16a ROM 17a Ink quantitative driver 17b Carrier liquid ejection driver 18 Concentration data Supply circuit

Claims (4)

[Claims] 1. A printer provided with a means for correcting a deviation occurring at a liquid landing position on a printing paper, depending on a concentration of a coloring liquid. 2. The head, in which the ejection port for the color liquid and the ejection port for the carrier liquid are vertically aligned in the print scanning direction, are provided.
Printer described in. 3. The printer according to claim 1, wherein the means for correcting the deviation at the liquid landing position includes means for advancing or delaying the discharge timing of the coloring liquid and the carrier liquid according to the concentration of the coloring liquid. . 4. The printer according to claim 1, further comprising a control circuit for controlling a print mechanism including a head, and the control circuit having a storage unit that stores time correction data corresponding to the concentration of the coloring liquid.