JP2000289226A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet recorder having a plurality of recording heads for ejecting ink while mixing in which reliability is enhanced by switching the mixing ratio of ink for every scan and suppressing fluctuation in the density of ink thereby simplifying the ink density control circuit and reducing the cost thereof. SOLUTION: Based on an image data delivered from a host computer 21, a main controller 22 recognizes a print mode and determines the number of scanning times for a same region. The main controller 22 drives a mixing/ ejecting driver 27 and a mixing valve driver 28 and sets a specified scan mixing ratio in the mixing chamber of a recording head 1. Printing is carried out by driving an ejection driver 26 according to a specified data while driving a carriage motor 4 for scanning. Subsequently, the main controller 22 sets a different scan mixing ratio in the mixing chamber and drives a feed motor 9 to move a recording material before starting second time scanning for printing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for recording an image on a recording medium by using a recording head capable of discharging ink from a discharge port, and more particularly to a serial scan type on-demand type ink jet recording apparatus. is there.

[0002]

2. Description of the Related Art At present, various recording methods have been developed as recording apparatuses. Among them, an ink jet recording method is excellent in quietness and high-speed recording because of non-contact with a recording medium. High density recording is possible,
They are widely used because they are easy to color and miniaturize.

[0003] Such ink jet recording apparatuses are broadly classified into a continuous jet type (continuous type) and an on-demand type.

[0004] As a feature of each of them, a continuous jet type ink jet recording apparatus continuously discharges ink droplets from a fine nozzle at a constant period, and after applying an electric charge to the droplets, deflects the droplets by an electric field, thereby arranging the droplets at predetermined positions. It is a method of landing, and as an advantage, it is possible to obtain high-speed, high-resolution image recording for one nozzle because of its high frequency response and the ability to make droplets finer. . On the other hand,
Since a mechanism for collecting ink is required and the overall configuration becomes large, this method is not suitable for multi-nozzle use.

[0005] On the other hand, an on-demand type ink jet recording apparatus uses the pressure of deformation of a piezo element attached to each minute nozzle or the pressure of bubbles generated by heating and boiling ink by a heating element. Is a method of landing at a predetermined position by controlling ink ejection at a position where an image is recorded.
Therefore, as an advantage, since the structure is simple, it is easy to form a multi-nozzle, and a small and inexpensive image recording apparatus is made possible. On the other hand, since the ink is not always flowing, nozzle clogging due to drying, alteration, dust, etc. of the ink is likely to occur, and it is necessary to prepare and provide a recovery mechanism.

Further, as a common drawback of the ink jet recording apparatus, it is difficult to modulate the density of ink droplets, and at present, a method of controlling the size of ink droplets in several stages for halftone gradation expression, It is realized only by a method of preparing ink of a density and discharging from different nozzles. The method of realizing the highest quality gradation expression is a method of recording by changing the density of ink droplets without changing the size of ink droplets. In a continuous jet type ink jet recording apparatus, US Pat. There is a method proposed in Japanese Patent No. 953, and an on-demand type ink jet recording apparatus is disclosed in Japanese Patent Application Laid-Open No. 5-201024 (US Pat.
No. 1,529) has been invented.

[0007]

However, in the system proposed in the above-mentioned U.S. Pat. No. 4,614,953, it is difficult to form a multi-nozzle which is a drawback of a continuous jet type ink jet recording apparatus. Because they are not mentioned, they cannot be used for small and inexpensive recording devices.

Then, there is a system proposed in Japanese Patent Application Laid-Open No. Hei 5-201024 (US Pat. No. 5,371,529).

In this method, since the density is controlled for each discharge nozzle, there is a concern that variation in ink density between nozzles is likely to occur.

In this system, a DA / C or a counter is required to control the ink mixing ratio by voltage, current or pulse width.

That is, when a multi-nozzle is formed by the method proposed in Japanese Patent Application Laid-Open No. Hei 5-201024 (US Pat. No. 5,371,529), DA / C or DA / C for controlling the density for each discharge nozzle is used. Since a counter is required, the control circuit becomes large-scale and the cost increases.

In addition, when a control signal line for controlling the density is required for each ejection nozzle, and the recording head is detachable, the number of electrical contacts increases, and the cost increases or the reliability decreases.

Further, in a so-called serial type recording apparatus which performs recording while reciprocating a carriage on which a recording head is mounted, the number of signal lines connected to the carriage is increased, and the cost is increased or the reliability is reduced.

[0014] In order to reduce the number of signal lines connected to the carriage, the data rate transferred to the carriage can be substantially reduced even if a DA / C or counter for controlling the density is mounted on the carriage. The number of nozzles × the number of gradations represents the number of bits × the ejection frequency. As the number of nozzles increases, the data rate increases, which is not practical for multi-nozzle operation.

Although the above-mentioned problem has been described with respect to a recording device having one recording head, it is a larger problem for a color recording device having a plurality of recording heads. is there.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a recording head that mixes and discharges a plurality of inks. An object of the present invention is to provide a highly reliable ink jet recording apparatus in which a control circuit for controlling is simple and inexpensive.

[0017]

According to an ink jet recording apparatus of the present invention, in an ink jet recording apparatus having a plurality of recording heads for mixing and discharging ink, a mixing ratio of the plurality of inks is switched for each scan. It is characterized by.

Further, the ink jet recording apparatus according to the present invention is characterized in that an image is formed by superimposing and scanning a print area.

Further, the ink jet recording apparatus according to the present invention is characterized in that the number of scans in which the print areas are superimposed and scanned and the mixing ratio of ink in each scan are determined according to the print mode.

Further, in the ink jet recording apparatus according to the present invention, the number of scans in which the printing area is superimposed and the mixture ratio of ink in each scan is determined by the number of colors or the number of gradations of image data input to the recording apparatus. Is determined according to

In the ink jet recording apparatus according to the present invention, the recording head includes a liquid chamber for a plurality of inks, a mixed liquid chamber for mixing the ink at a required mixing ratio, and a discharge port for discharging the ink. Wherein the liquid flow path communicating the liquid chamber and the mixed liquid chamber has different diameters having a fixed ratio corresponding to the mixing ratio.

Further, in the ink jet recording apparatus of the present invention, the ratio of the diameter of the liquid flow path is one time, two times, and four times that of the discharge port, corresponding to the mixing ratio of the ink. It is characterized by.

Further, the ink jet recording apparatus of the present invention is characterized in that a control valve is provided in the liquid flow path, and the control valve has a size corresponding to the mixing ratio of the ink.

Further, in the ink jet recording apparatus according to the present invention, the control valve is formed by laminating a thin film piezoelectric body and a metal thin film electrode.

An ink jet recording apparatus according to the present invention is characterized in that the recording head has an electrothermal transducer for generating thermal energy used for discharging ink.

Further, the ink jet recording apparatus of the present invention is characterized in that the electrothermal transducer generates electric energy which causes film boiling of the ink.

In this specification, the term “record” (hereinafter, also referred to as “record”) refers not only to the formation of significant information such as characters and figures, but also to significant or insignificant. Regardless of whether or not the image is visualized so that a human can perceive it visually, the case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or the medium is processed is also referred to.

Here, the term "recording medium" refers not only to paper used in a general recording apparatus but also to a wide range of materials that can accept ink, such as cloth, plastic films, metal plates, and the like.

Further, the term "ink" is to be interpreted broadly as in the definition of "recording" described above. When applied to a recording medium, it forms an image, a pattern, a pattern, or processes the recording medium. Liquid that can be provided to

In the present specification, the term nozzle generally refers to a discharge port, a liquid path communicating with the discharge port, and an element that generates energy used for ink discharge, unless otherwise specified.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the ink jet recording apparatus of the present invention having the above-described configuration, in an ink jet recording apparatus having a recording head for mixing and discharging a plurality of inks, the mixing ratio of the plurality of inks is scanned. There is no need to control the ink density for each nozzle and pixel for switching each time, or it is possible to form pixels with different nozzles to form an image by superimposing and scanning the print area. In addition, in order to determine the number of scans in which the print area is superimposed and scanning and the mixture ratio of ink in each scan according to the print mode, printing can be performed in an optimal printing method according to the print mode. In addition, the number of scans for scanning with the print area superimposed and the mixing ratio of ink in each scan are input to the recording device. To determine in accordance with the number of colors or the number of gradations of the image data to be, it can be printed in correspondence with the number of colors or gray scale number of the plurality of image data.

Hereinafter, embodiments of the ink jet recording apparatus of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a schematic perspective view showing a schematic configuration of an ink jet recording apparatus to which the present invention is applied.

As shown in FIG. 1, an ink jet recording apparatus to which the present invention is applied includes a recording head 1 for performing recording by discharging ink, a carriage 2 on which the recording head 1 is mounted, and reciprocating movement of the carriage 2. A carriage motor 4 for driving via a timing belt 5 to perform
An ink tank 7 attached to the carriage 2, a recording material (not shown), which is a recording medium, is arranged for recording, and a platen 8 for driving the recording material by a feed motor 9; And a suction pump unit 10 provided with a wiper 12.

In the illustrated ink jet recording apparatus of the present invention, the recording head 1 is mounted on the carriage 2 in a posture for ejecting ink downward in the drawing, and the recording is performed while moving the carriage 2 along the guide shaft 3. An image is formed on a recording material (not shown) which is a medium. The reciprocating movement of the carriage 2 in the left-right direction is performed via the timing belt 5 by the rotation of the carriage motor 4. The carriage 2 has an engaging claw 6.
The engaging claw 6 is engaged with the engaging hole 7a of the ink tank 7, so that the ink tank 7 is fixed to the carriage 2 and is detachably attached.

Accordingly, in such an ink jet recording apparatus, the carriage 2 moves and recording is performed on the recording material by the recording head 1. The recording operation is interrupted, the recording material positioned on the platen 8 is fed by a predetermined amount by driving the feed motor 9, and then the carriage 2 is again moved along the guide shaft 3 by the recording head 1 to move the carriage 2 again. Is formed.

A suction pump unit 10 is disposed on the right side (FIG. 1) of the apparatus main body of the ink jet recording apparatus. The suction pump unit 10 has an ink suction cap 11, a wiper 12, and a pump (not shown).
Etc. are attached. Also, the suction pump unit 10
Is to perform a recovery operation for maintaining a good ink discharge state of the recording head 1 by a suction motor (not shown), and a suction operation for changing the ink concentration in the mixed liquid chamber 208 of the recording head 1. It is made possible.

FIG. 5 is a schematic perspective view of the recording head 1 used in the present invention. As shown, the recording head 1 of the present invention has a first substrate made of, for example, glass, ceramic, metal, or the like. A desired number of ejection energy generating elements 202, 203, and 204 are provided on 201. The first substrate 201 is provided on the liquid flow path 20.
5, 206, 207, mixed liquid chamber 208 and liquid chamber 20
It also functions as the bottom wall for 9, 210.

The ejection energy generating elements 202, 203 and 204 provided on the substrate 201
1, 212, and 213 for generating and applying energy for discharging ink, and includes, for example, an electrothermal transducer, a piezoelectric element, and the like. Incidentally, in the present embodiment, an electrothermal converter is used as the ejection energy generating element 202, and this ejection energy generating element 20
2 is configured to heat the ink in the vicinity of the liquid flow path 205 to generate ejection energy, so that the ink in the mixed liquid chamber 208 pops out to form an image on a recording material. A piezoelectric element is used as the ejection energy generating element 204, and ink near the liquid flow path 206 or the liquid flow path 207 is pushed out by mechanical vibration of the piezoelectric element, and ink in the liquid chamber 209 or the liquid chamber 210 is discharged. The energy to be supplied to the mixed liquid chamber 208 is generated. In addition, these ejection energy generating elements 202, 203, 2
An electrode (not shown) to which a drive signal is input is connected to 04.

One end of the liquid flow path 205 is thin and is open to the outside, and this open part is a discharge port 211. The other end of the liquid flow path 205 communicates with a common mixed liquid chamber 208. Further, each liquid flow path 20
5, a discharge energy generating element 202 is disposed at the bottom, and in this embodiment, 16 liquid flow paths 205 are provided.

In the illustrated recording head 1, the liquid flow path 20
One end of each of 6, 6 and 207 is thinner, and serves as discharge ports 212 and 213. These discharge ports 212,
213 are all in common communication with the mixed liquid chamber 208. Further, the other end of the liquid flow path 206 communicates with the common liquid chamber 209, and the other end of the liquid flow path 207 communicates with the common liquid chamber 210. Each liquid flow path 206, 207
The substrate 201 at the bottom of the
In this embodiment, three liquid flow paths 206 having different flow path diameters and three liquid flow paths 207 having the same flow path diameter are provided.

Control valves 214 and 215 are provided in front of the discharge ports 212 and 213 to prevent the ink in the mixed liquid chamber 208 from flowing back to the liquid flow paths 206 and 207.

On the substrate 201 of the recording head 1, a filling member 216 serving as a wall of an ink flow path and a liquid chamber is laminated and overlapped.
17 are superimposed. The liquid chamber 2 of this structural member 217
09, 210, the ink supply port 2
18 and 219 are formed.
Inks 18 and 219 are supplied with inks having different compositions.

The control valves 214 and 215 have a structure in which a thin film piezoelectric member 220 and a metal thin film electrode 221 are laminated and stacked as shown in FIG.
As shown in FIG. 7, the control valves 214 and 215 warp due to a change in the thickness of the thin film piezoelectric member 220, and
3 can be controlled independently of each other. By controlling the opening and closing of the control valves 214 and 215, the inks in the liquid chambers 209 and 210 can be mixed at an arbitrary mixing ratio.
The mixing can be performed in the mixed liquid chamber 208. In this embodiment, the diameters of the discharge ports 212 and 213 are
There are three types, 1x, 2x and 4x, compared to
For example, when the mixing ratio of the ink in the liquid chamber 209 and the ink in the liquid chamber 210 is 1: 4, the smallest one of the control valves 214 and the largest one of the control valves 215 are opened, and the other valves are closed. You can do it. At this time, the ejection energy generating element 2
By controlling the driving of the ink jet heads 03 and 204 in synchronization with the driving of the ejection energy generating element 202 and by making them equal to the ejection amount, the pressure of the ink in the mixed liquid chamber 208 is kept constant. The accuracy is further improved.

In FIG. 5, a discharge port 222 is disposed at a position slightly away from the 16 discharge ports 211, and communicates with the mixed liquid chamber 208 via a liquid flow path 223. The purpose of the use of the liquid flow path 223 is to change the mixing ratio of the ink in the mixed liquid chamber 208 or to change the mixed liquid chamber 20.
In cleaning the liquid channel 8 and the liquid flow path 205, the liquid flow path 223 can function as an air communication port for emptying the ink in the mixed liquid chamber 208, that is, an air hole. FIGS. 3 and 4 show the recovery operation for this purpose.
This will be described in detail later. Further, it is possible to install a discharge energy generating element 224 at the bottom of the liquid flow path 223, and it is possible to discharge the excess ink in the mixed liquid chamber 208 by itself instead of suctioning the pump by the recovery device. It is.

Next, the structure of the suction pump unit 10 will be described in detail with reference to FIGS.

The suction pump unit 10 and the ink suction cap 11 are driven by a suction motor (not shown). FIG. 3 shows the ink suction cap 11. The ink suction cap 11 as an ink receiving means is provided at least for recording so as to be able to elastically press against the ejection port group forming surface of the recording head 1 during capping. Head 1
It is preferable that the contact portion is formed using an elastic member such as rubber. Further, the shape of the ink suction cap 11 is such that a rib 102 which is in close contact with the ejection port group forming surface of the recording head 1 and a rib 103 which blocks the recording ejection port 211 and the recovery air communication port 222 are provided. The suction space 10 is formed by these ribs 102 and 103.
4a and 104b are formed. Each of the suction spaces 104a, 104b has a suction tube 105a, 1
05b is connected and in communication.

The tubes 105a and 105b extending from the ink suction cap 11 are
0 and 120 are arranged in an arc shape in grooves provided in the pump bases 111 and 121, respectively.
0 and 120 are fixed between columnar guide rollers 113 and 123 which rotate around guide roller shafts 112 and 122 attached to pump bases 111 and 121, respectively. In addition, these tubes 105a and 105b
At least a portion between the pump bases 111 and 121 and the guide rollers 113 and 123 has flexibility, and a part that rotates about pressure roller shafts 114 and 124 attached to the guide rollers 113 and 123 is provided. Pressure roller 115,
The tube 105a and 105b are configured to pressurize the tube 105a and the tube 105b respectively when the 125 rotates to the arc-shaped portions of the pump bases 111 and 121. The ink suction cap 11 and the suction pumps 110 and 120 are driven by a suction motor (not shown).

In the above configuration, to perform the suction operation,
With the ink suction cap 11 pressed against the recording head 1, the guide roller 113 of the suction pump 110 is rotated in the direction of arrow a in FIG. Therefore, when the pressure roller 115 of the suction pump 110 is at the position X, the pressure roller 115
Does not pressurize the tube 105a, the suction space 104a communicates with the atmosphere. Next, the pressure roller 115
Comes to the Y position, the tube 105a
5 crushes it and cuts off communication with the atmosphere. Therefore, if the guide roller 113 is continuously rotated in the direction of arrow a, the pressure roller 115 rotates in the direction b and moves to the Z position while crushing the tube 105a.
During this time, a negative pressure is generated in the crushed tube 105a due to a change in volume, and a suction operation from the ejection port 211 of the recording head 1 is performed.

By rotating the guide roller 123 based on the same operation principle, the suction operation from the discharge port 222 can be performed in the same manner.

By controlling the recording head 1, the ink suction cap 11, and the suction pumps 110 and 120,
The following three types of recovery operations are possible.

1) Obstructions on all ink flow paths are removed. For this purpose, first, the ink suction pumps 110, 12
The 0 pressure rollers 115 and 125 are moved to the position of X. Next, the ink suction cap 11 is pressed against the recording head 1. Next, all of the control valves 214 and 215 in the recording head 1 are opened. The guide rollers 113 and 123 are rotated in the direction a so that the pressure rollers 115 and 125 of the suction pumps 110 and 120 are at the same position and at the same speed. While the pressure rollers 115 and 125 move from the Y position to the Z position, ink is sucked from the ejection ports 211 and 222.

2) When changing the ink concentration in the mixed liquid chamber 208, once discharging all the existing ink is a method of reducing waste ink. To do so, first, pressurized rollers 115, 12 of suction pumps 110, 120
Move 5 to the X position. Next, the ink suction cap 1
1 is pressed against the recording head 1. Next, the recording head 1
All of the control valves 214 and 215 are closed. The pressure roller 125 of the suction pump 120 is fixed at the position X.
Next, only the guide roller 113 of the suction pump 110 is rotated in the direction a. Pressing roller 115 moves from position Y to Z
Ink is sucked from the ejection port 211 and air enters through the ejection port 222 during the movement to the position.

3) When the ink jet recording apparatus is set in the storage state, it is necessary to prevent the ink from hardening in the recording head 1. For this purpose, the mixed liquid chamber 208 is filled with only one ink (ink containing no color). First, the pressure roller 1 of the suction pumps 110 and 120 is used.
15 and 125 are moved to the X position. Next, the ink suction cap 11 is pressed against the recording head 1. Next, all of the control valves 214 (or one of the control valves 215 on the ink side not including the color) in the recording head 1 are opened. Pressure roller 11 of suction pumps 110 and 120
The guide rollers 113 and 123 are rotated in the direction of arrow a so that the rollers 5 and 125 are at the same position and at the same speed. While the pressure rollers 115 and 125 move from the Y position to the Z position, ink is sucked from the ejection ports 211 and 222.
Since only the control valve 214 side is open, only the ink in the liquid chamber 209 flows into the mixed liquid chamber 208.

As described above, the ink suction operation of the recording head 1 of the ink jet recording apparatus is performed, and a necessary recovery process is performed.

FIG. 2 is a block diagram showing a schematic configuration of the ink jet recording apparatus of the present invention.

Reference numeral 21 denotes a host computer, and reference numeral 22 denotes a main controller of the ink jet recording apparatus. The main controller 22 includes a CPU, a ROM, a RAM, a gate array, and the like.
1 to control various drivers.

A motor driver 23 drives the carriage motor 4 according to an instruction from the main controller 22.

A motor driver 24 drives the feed motor 9 according to an instruction from the main controller 22.

A motor driver 25 drives the suction motor 29 in accordance with an instruction from the main controller 22.

An ejection driver 26 drives the ejection energy generating element 202 of the recording head 1 according to an instruction from the main controller 22.

A mixed ejection driver 27 drives the ejection energy generating element 203 of the recording head 1 according to an instruction from the main controller 22.

A mixing valve driver 28 drives the control valve 214 of the recording head 1 in accordance with an instruction from the main controller 22.

Next, a method for setting the inside of the mixed liquid chamber 208 of the recording head 1 to a desired mixing ratio will be described.

In this embodiment, since the diameters of the discharge ports 212 and 213 are three times as large as those of the discharge ports 211, ie, one time, two times and four times, the mixing ratio is from 7: 0 to 0. : 7.

First, the case where the mixed solution chamber 208 is empty will be described.

For example, when the mixing ratio of the ink in the liquid chamber 209 and the ink in the liquid chamber 210 is 1: 4, the main controller 22 drives the mixing valve driver 28 and the mixing / discharging driver 27 and the other valves are closed. The mixing ratio can be set to 1: 4 by driving the ejection energy generating elements 203 and 204 in the state.

When the mixed liquid chamber 208 is filled with ink, the recording head 1 is separated from the recording material, and the ink is ejected to a place other than the recording material (for example, a waste ink port is provided). There is also a method of performing mixing. Specifically, the smallest one of the control valves 214 and the largest one of the control valves 215 are opened, the other valves are closed, the discharge energy generating elements 203 and 204 are driven, and the discharge energy generation is performed. The element 202 and the ejection energy generating element 224 may be driven such that the pressure of the ink in the mixed liquid chamber 208 is kept constant.

The ink jet recording apparatus of this embodiment has two printing modes, a high quality printing mode and a high speed printing mode. These printing modes can be selected according to the purpose of use by the user. The print mode may be set by the user operating a switch on the inkjet recording apparatus. In this embodiment, the print mode is set by a print mode setting command from the host computer 21.

Table 1 in FIG. 8 shows the number of scans for scanning the same area in each of the two print modes of the high-quality print mode and the high-speed print mode of the ink jet recording apparatus of the present embodiment, and the mixing ratio in each scan. It is. In this embodiment, the liquid chamber 209 contains 100% ink, the liquid chamber 210 contains a diluent, and the ratio in the table is the mixing ratio of the liquid chamber 209 to the liquid chamber 210. .

Next, the operation of the ink jet recording apparatus according to the first embodiment of the present invention will be described.

In this embodiment, it is assumed that image data of 256 gradations of 8 bits is sent from the host computer 21.

First, it is assumed that a print mode setting command designating high-speed printing has been sent from the host computer 21 to the main controller 22 prior to an image. The main controller 22 recognizes the print mode, and determines the number of scans for scanning the same area to 2 according to Table 1 in FIG.

Next, the main controller 22 binarizes the 8-bit image data sent from the host computer 21 by a method such as ternary error diffusion. Assuming that the outputs of the ternary error diffusion are 0, 1, and 2, 0 corresponds to non-ejection and 1
Corresponds to a mixing ratio of 1: 1 (concentration 50%), and 2 corresponds to a mixing ratio of 1: 0 (concentration 100%). As will be described later, outputs 1 and 2 of the ternary error diffusion are scans 1 and 2 respectively.
Is the print data at the time of.

Next, the main controller 22 drives the mixing / discharging driver 27 and the mixing valve driver 28 to move the inside of the mixed liquid chamber 208 in the recording head 1 to 1: 0 (scan 1 mixing ratio in Table 1 of FIG. 8). (Concentration 100%). Next, the main controller 22 drives and drives the ejection motor 26 in accordance with the data of the output 2 of the ternary error diffusion while scanning by driving the carriage motor 4.

When one scan is completed, the main controller 22 moves the carriage 2 to the suction pump unit 10 and fills the mixed liquid chamber 208 in the recording head 1 with the scan 2 mixing ratio shown in Table 1 of 1: 1 (concentration 50%). ).
Further, the main controller 22 drives the feed motor 9 to move the recording material by half the length of the nozzle row.

The main controller 22 drives the carriage motor 4 to perform the second scan while
Ejection driver 26 according to the data of output 1 of the value error diffusion.
Is driven to print.

When one scan is completed, the main controller 22 moves the carriage 2 to the position of the suction pump unit 10 and fills the mixed liquid chamber 208 in the recording head 1 with 1: 0 (the scan 1 mixing ratio in Table 1). Concentration 100
%). Thereafter, printing is performed in the same manner.

(Embodiment 2) Also in this embodiment, the ink jet recording apparatus is provided with two printing modes, a high quality mode and a high speed printing mode, and image data of 256 gradations of 8 bits is transmitted from the host computer 21. And It is also assumed that the liquid chamber 209 of the recording head 1 contains 100% ink and the liquid chamber 210 contains a diluting liquid.

In this embodiment, printing is performed by a so-called multi-scan method in which substantially the same pixel is composed of a plurality of ink droplets. Therefore, in the present embodiment, a print head having the same configuration as the print head of the first embodiment is used, but the ejection amount per nozzle is smaller than that of the print head of the first embodiment.

Table 2 in FIG. 9 shows the number of scans for scanning the same area in each of the two print modes of the high-quality print mode and the high-speed print mode of the recording apparatus of the present embodiment, and the mixing ratio in each scan. is there. In this embodiment, the liquid chamber 209 contains 100% ink,
10 contains a diluent, and the ratio in the table is
9: Mixing ratio of the liquid chamber 210. As can be seen from Table 2 in FIG. 9, when the densities of scans 1, 2, and 3 are added, a density of 10
It is mixed in each scan to be 0%. In actuality, the sum is greatly affected by the ink penetration speed into the recording material and the ejection interval, and is not a simple addition.
It shall be 0%.

First, a print mode setting command for designating high-speed printing is sent from the host computer 21 to the main controller 22 prior to an image. The main controller 22 recognizes the print mode, and determines the number of scans for scanning the same area to 2 according to Table 2 in FIG.

Next, the main controller 22 quaternizes the 8-bit image data sent from the host computer 21 by a method such as quaternary error diffusion. Assuming that outputs of the quaternary error diffusion are 0, 1, 2, and 3, 0 corresponds to non-discharge, 1 corresponds to a mixing ratio of 1: 2 (density of 33%), and 2 corresponds to a mixing ratio of 2: 1. 3 corresponds to printing with a mixing ratio of 1: 2 (33% density) and a mixing ratio of 2: 1 (67% density) divided into two scans.

That is, the output of OR of the output 1 of the quaternary error diffusion and the output 3 is the print data at the time of scan 1. The OR of the output 2 of the quaternary error diffusion and the output 3 is the print data for scan 2. Hereinafter, printing is performed in the same manner as in the first embodiment.

(Embodiment 3) In this embodiment, two bits of four bits are used.
It is assumed that gradation image data is sent from the host computer 21. In this embodiment, a print head having the same configuration as the print head of the first embodiment is used.

In this embodiment, printing is performed according to Table 3 in FIG.

Since the number of gradations is four, Table 3 in FIG.
, The number of scans for scanning the same area is determined to be 3. Further, assuming that the data of four gradations is 0, 1, 2, and 3, 0 corresponds to non-discharge and 1 corresponds to a mixture ratio of 1: 2 (density of 3
2 corresponds to a mixing ratio of 2: 1 (concentration 67%), and 3 corresponds to a mixing ratio of 1: 0 (concentration 100%). In the first scan, the mixture ratio was 1: 2 (33% density), and in the second scan, the mixture ratio was 2: 1 (6 density).
7%) In the third scan, the mixture ratio was 1: 0 (concentration 10).
0%).

(Other Embodiments) By the way, Embodiment 1,
In 2, the main controller 22 performs the error diffusion processing, but the error diffusion processing may be performed by the host computer 21.

It has been described that one of the liquid chamber 209 and the liquid chamber 210 uses ink containing no color, and that inks having different densities are produced in the mixed liquid chamber 208. Of ink in the liquid chamber 21
The mixing ratio may be controlled by supplying cyan ink to 0.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for discharging ink, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which a change in the state of ink is caused by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described, for example, in US Pat. No. 4,723,129, and US Pat.
It is preferable to use the basic principle disclosed in 740,796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or the liquid path holding the liquid (ink). Applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, thereby generating heat energy in the electrothermal transducer, and thereby forming a recording head. This is effective because a film in the liquid (ink) corresponding to the driving signal can be formed one by one by causing film boiling on the heat acting surface. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet.
When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. U.S. Pat. Nos. 4,463,359
No. 4,345,262 are suitable. In addition, US Pat. No. 4,313,12 of the invention relating to the temperature rise rate of the heat acting surface.
If the conditions described in the specification of JP-A No. 4 are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angle liquid flow path) as disclosed in the above-mentioned respective specifications, The present invention also includes a configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600 which disclose a configuration in which a heat acting portion is arranged in a bending region. It is. In addition, Japanese Unexamined Patent Publication No. Sho 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, the recording head fixed to the apparatus main body or the electric connection with the apparatus main body and the ink from the apparatus main body when attached to the apparatus main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

Further, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, and the like as the constitution of the recording apparatus of the present invention since the effect of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

Further, the types and the number of the recording heads to be mounted are, for example, not only one provided for a single color ink but also a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to the printing mode of only the mainstream color such as black, but may be any one of integrally forming the printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color or color mixing.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the ink liquefies by the application according to the recording signal of the heat energy,
The present invention is also applicable to a case in which an ink having a property of being liquefied for the first time by the application of thermal energy, such as an ink in which a liquid ink is ejected or an ink which starts solidifying when it reaches a recording medium, is used. In such a case, the ink is held in a state of being held as a liquid or solid substance in the concave portion or through hole of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus of the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also for a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may take a form.

[0099]

According to the first aspect of the present invention having the above-described structure,
The inkjet recording apparatus according to the aspect of the invention is an inkjet recording apparatus including a recording head that mixes and discharges a plurality of inks. Since the mixing ratio of the plurality of inks is switched for each scan, the number of colors or gradations of a plurality of image data is changed. Printing can be suitably performed according to the number.

Further, in the ink jet recording apparatus according to the second aspect of the present invention, since an image is formed by scanning a print area in a superimposed manner, a clear image can be clearly printed.

Further, in the ink jet recording apparatus according to the third aspect of the present invention, the number of scans in which the print areas are superimposed and scanned and the mixing ratio of ink in each scan are determined according to the print mode. It is possible to print beautifully with a proper mixing ratio of ink.

Further, in the ink jet recording apparatus according to a fourth aspect of the present invention, the number of scans in which the print area is superimposed and the mixture ratio of ink in each scan are determined by the color of the image data input to the recording apparatus. Since it is determined according to the number or the number of gradations, printing can be suitably performed in accordance with the number of colors or the number of gradations of a plurality of image data.

According to a fifth aspect of the present invention, in the ink jet recording apparatus, the recording head includes: a liquid chamber for a plurality of inks; a mixed liquid chamber for mixing the inks at a required mixing ratio; It has a discharge port for discharging, and the liquid flow path communicating the liquid chamber and the mixed liquid chamber has a fixed ratio corresponding to the mixing ratio, and has different diameters, so with a simple configuration, It can be manufactured to operate reliably with high reliability.

According to a sixth aspect of the present invention, in the ink jet recording apparatus, the ratio of the diameter of the liquid flow path is one time, two times, or one time with respect to the discharge port, corresponding to the mixing ratio of the ink.
Since it is four times, the mixing ratio of the ink can be suitably determined.

Further, in the ink jet recording apparatus according to the present invention, a control valve is provided in the liquid flow path, and the control valve has a size corresponding to the mixing ratio of the ink. The control circuit including the control circuit can be manufactured easily and with high reliability.

Further, in the ink jet recording apparatus according to the eighth aspect of the present invention, since the control valve is formed by laminating a thin film piezoelectric body and a metal thin film electrode, the control valve can be manufactured at low cost. It can be made to work reliably.

The ink jet recording apparatus according to the ninth aspect of the present invention has an electrothermal converter for generating thermal energy used for discharging the ink by the recording head. By discharging, high density and high definition of recording can be achieved, and clear recording can be obtained.

In the ink jet recording apparatus according to a tenth aspect of the present invention, since the electrothermal transducer generates electric energy that causes film boiling of the ink, the ink is ejected using the electric energy. Higher recording density and higher definition can be achieved, and clear recording can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an ink jet recording apparatus according to the present invention.

FIG. 2 is a block diagram of an ink jet recording apparatus according to the present invention.

FIG. 3 is a perspective view showing a suction cap in the recovery device.

FIG. 4 is a side view showing a suction pump in the recovery device.

FIG. 5 is a schematic perspective view of the ink jet recording head of the embodiment.

FIG. 6 is a side view showing the configuration of the control valve used in FIG.

FIG. 7 is a diagram illustrating a change when a voltage is applied to the control valve of FIG. 5;

FIG. 8 is a diagram showing Table 1 showing the number of scans for scanning the same area in each of two print modes of a high-quality print mode and a high-speed print mode of the inkjet recording apparatus of the present invention, and a mixing ratio in each scan.

FIG. 9 is a table showing the number of scans for scanning the same area in each of two print modes of a high-quality print mode and a high-speed print mode of the inkjet recording apparatus of the present invention, and Table 2 showing a mixture ratio in each scan.

FIG. 10 is a diagram showing Table 3 showing the number of scans for scanning the same area in each of two print modes of a high-quality print mode and a high-speed print mode of the inkjet recording apparatus of the present invention, and a mixing ratio in each scan.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Carriage 3 Guide shaft 4 Carriage motor 5 Timing belt 6 Engagement claw 7 Ink tank 8 Platen 9 Feed motor 10 Suction pump unit 11 Ink suction cap 23 Motor driver 24 Motor driver 25 Motor driver 26 Discharge driver 27 Mixing discharge driver 28 Mixing valve driver 29 Suction motor 102 Suction cap 103 Rib 104a, 104b Suction space 105a, 105b Suction tube 111, 121 Pump base 113, 123 Guide roller 202, 203, 204 Discharge energy generating element 205, 206, 207 Liquid flow Channel 208 Mixed liquid chamber 209, 210 Liquid chamber 211, 212, 213 Discharge port 214, 215 Control valve 216 Filling member 217 Structural member 218, 219 The supply port 220 film piezoelectric member 221 thin film electrodes 222 discharge port 223 liquid flow path 224 discharge energy generating elements

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Sohei Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Noriyuki Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Ryo Ito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masafumi Wataya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F Terms (reference) 2C056 EA04 EA11 EC18 EC44 EC74 EC80 ED03 ED07 EE11 FA03 KB03 KB09 2C057 AF39 AG32 AG46 AG76 AM14 AN01 CA04 CA07 CA08

Claims (10)

[Claims] 1. An ink jet recording apparatus comprising a recording head for mixing and discharging a plurality of inks, wherein the mixing ratio of the plurality of inks is switched for each scan. 2. The ink jet recording apparatus according to claim 1, wherein an image is formed by scanning a print area in a superimposed manner. 3. The method according to claim 1, wherein the number of scans in which the print areas are superimposed and scanned and the mixing ratio of ink in each scan are:
3. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is determined according to a print mode. 4. The method according to claim 1, wherein the number of scans in which the print area is superimposed and scanned and the mixing ratio of ink in each scan are:
3. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is determined according to the number of colors or the number of gradations of image data input to the recording apparatus. 5. The recording head has a liquid chamber for a plurality of inks, a mixed liquid chamber for mixing the ink at a required mixing ratio, and a discharge port for discharging the ink. 2. The ink jet recording apparatus according to claim 1, wherein the liquid flow paths communicating the chamber and the mixed liquid chamber have different diameters having a fixed ratio corresponding to the mixing ratio. 6. The ratio of the diameter of the liquid flow path to the discharge port is 1 time, 2 times, or 4 times, corresponding to the mixing ratio of the ink.
6. The ink jet recording apparatus according to claim 5, wherein the number is double. 7. The ink jet recording apparatus according to claim 6, wherein a control valve is provided in the liquid flow path, and the control valve has a size corresponding to a mixing ratio of the ink. 8. The ink jet recording apparatus according to claim 7, wherein the control valve is formed by laminating a thin film piezoelectric body and a metal thin film electrode. 9. The ink jet recording apparatus according to claim 1, wherein the recording head has an electrothermal transducer for generating thermal energy used for discharging ink. 10. The ink jet recording apparatus according to claim 9, wherein said electrothermal converter generates electric energy for causing film boiling of the ink.