JPH05270013A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To make it possible to detect an inclination of an ink jet record head. CONSTITUTION:There are provided a moving coil 12 for detecting whether or not there is a hit of a droplet of ink delivered from ink jet record heads 1, 2, 3, 4, a carriage 5 for relatively moving the heads 1, 2, 3, 4 and the coil 12, and a shielding member 11 which is provided between the heads 1, 2, 3, 4 and the coil 12 to shield part of ink droplets delivered from a plurality of nozzles from flying to the coil 12.

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 having means for detecting a mounting position deviation (registration) of an ink jet recording head having a plurality of nozzles.

[0002]

2. Description of the Related Art In recent years, the spread of personal computers, computer graphics, and CAD (Computer Aid)
ded Design) and the like have become easy to handle color image information, and the demand for color printers for its output is increasing. There are various recording methods for color printers,
There are a laser beam electrophotographic system, an electrostatic photography system, a lithographic recording system, a thermal transfer recording system, a wire dot recording system, an inkjet recording system and the like. There is an ink jet recording method as one of recording methods of a small-sized, inexpensive, and high-definition color printer, each of which has its own characteristics.

Generally, a color printer using an ink jet recording system has four ink jet recording heads having several tens of nozzles arranged on a carriage in parallel with the nozzle arrangement direction. Responsible for recording magenta, cyan, and black. There is a recording paper in the direction opposite to the nozzles, the carriage scans the vicinity of the surface of the recording paper in the nozzle arrangement direction, and each inkjet recording head performs recording of each color. Each time the recording paper is scanned, the recording paper is conveyed in a direction corresponding to the nozzles of the inkjet recording head in the vertical direction of the scanning, and color recording is performed on the entire surface of the recording paper.

However, in these color printers, for example, when recording red characters, the characters recorded by the inkjet recording head for yellow and the characters recorded by the inkjet recording head for magenta exactly match on the recording paper. It must be. Considering recording such as green and blue, high accuracy is required for mounting the four inkjet recording heads arranged on the carriage. As a means for avoiding this, color misregistration in the scanning direction of the carriage on the recording paper is corrected by shifting the operation timing of each inkjet recording head on the time axis, and the color shift in the direction perpendicular to the scanning direction of the carriage on the recording paper is corrected. The color misregistration is determined by using an inkjet recording head in which the total number of nozzles of the inkjet recording head is larger than the number of nozzles corresponding to the recording width for printing in one scan, and determining the arrangement range position of the number of nozzles corresponding to the recording width for each inkjet recording head. It has been proposed to perform correction by changing the color shift amount in the vertical direction.

[0005]

In this case, it is necessary to have a means for detecting the color shift amount in advance in order to determine the correction amount. The color misregistration amount detecting means may be a method of recording a test pattern on which a color misregistration can be easily recognized on a recording paper and the operator detecting the color misregistration amount to determine a correction amount, or a color printer having a pattern of the test pattern. There is a method in which a recognition unit is provided to detect the color misregistration amount and automatically determine the correction amount to perform the correction. However, in the former case, the operator is troubled. Further, since it is difficult to quantitatively recognize the amount of color misregistration, it is necessary to output the test pattern after the correction result many times to finely adjust the correction amount. In the latter case, an expensive high-precision pattern detector is required for each color, a mechanism for switching color filters with one pattern detector is required, or a more expensive color pattern detector is required.
Further, an optical system for forming an image of the test pattern on the recording paper on the detector is required, which is very expensive.

In any case, when each nozzle array is inclined with respect to the scanning direction, the position of each nozzle in the scanning direction is not constant. Therefore, the landing positions of the nozzles are different from each other.

An object of the present invention is to provide an ink jet recording apparatus capable of easily detecting the inclination of the ink jet recording head.

Another object of the present invention is to provide an ink jet recording apparatus which can easily detect the positional deviation of each ink jet recording head when it has a plurality of ink jet recording heads.

[0009]

An ink jet recording apparatus of the present invention has an ink jet recording head having a plurality of nozzles, and the ink jet recording head and a recording medium are relatively scanned in a direction perpendicular to an arrangement direction of the plurality of nozzles. A scanning unit, a landing detection unit that is in a stationary relationship with the recording medium and that detects whether or not ink droplets ejected from the inkjet recording head have landed, and a moving unit that relatively moves the inkjet recording head and the landing detection unit. And a shielding unit that is provided between the ink jet recording head and the landing detection unit and that blocks a part of a plurality of ink droplets from a plurality of nozzles from flying to the landing detection unit. ..

Further, the ink jet recording apparatus of the present invention is characterized in that at least a part of the boundary line between the blocking and blocking of the shielding means is parallel to the nozzle array direction.

Further, the ink jet recording apparatus of the present invention has a plurality of ink jet recording heads dedicated to a plurality of colors.

[0012]

In the above structure, the ink jet recording head to be measured for measuring the displacement of the mounting position of the nozzles in the scanning direction is ejected while moving the carriage from the vicinity of the blocking / non-blocking boundary portion which is parallel to the nozzle arrangement direction of the shielding means. To do. The landing detection means detects landing non-landing at any time. With the above-described configuration, the mounting position deviation in the nozzle scanning direction of the inkjet recording head to be measured is recognized by recognizing at which position in the scanning direction the inkjet recording head to be ejected has reached the landing detection means. Can be measured by the position detection system. If the above-mentioned scanning is performed for each inkjet recording head, each positional deviation can be measured, and the operation timing correction value of the inkjet recording head on the time axis can be determined.

[0013]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. The four ink jet recording heads 1, 2, 3, 4 are ink jet recording heads in which 64 nozzles (not shown) are arranged at a density of 360 nozzles / inch, and discharge energy is applied to a liquid passage near the discharge port at the tip of each nozzle. A heating element (not shown) for generating the heat is provided. The heating element generates heat in response to the applied electric pulse, thereby causing the inks respectively supplied from the ink supply tubes 7A, 7B, 7C, 7D to film-boil, and the bubbles are grown due to the film boiling. Ink is ejected from the ejection port.

The inkjet recording head 1 is an inkjet recording head for yellow recording, the inkjet recording head 2 is an inkjet recording head for magenta recording, the inkjet recording head 3 is an inkjet recording head for cyan recording, and an inkjet recording head 4. Is an inkjet recording head for recording black.

Each ink jet recording head 1,
The ejection frequencies of 2, 3 and 4, that is, the drive frequency of the heating element is 2 kHz. The carriage 5 is mounted on which the ink jet recording heads 1, 2, 3, 4 are mounted to move, and the movement of the carriage 5 is guided by two guide shaft shafts 6A and 6B which are slidably engaged in a part thereof. It is done while being done. In this embodiment, the carriage 5 is used as a moving unit that relatively moves the inkjet recording heads 1, 2, 3, 4 and a moving coil 12 described later.

The flexible cable 8 transmits a drive signal corresponding to image information from a CPU (not shown) in the control section of the apparatus to a heating element provided in the ink jet recording heads 1, 2, 3, 4 from an ink tank (not shown). It is for. Each of the ink supply tubes 7A, 7B, 7C, 7D and the flexible cable 8 is made of a flexible member so that it can follow the movement of the carriage 5. Further, the carriage 5 is stretched in parallel with the guide shafts 6A and 6B and is connected to a part of a belt (not shown) for moving the carriage 5, and the belt is driven by a carriage motor (not shown) to drive the carriage 5. It is configured so that it can be moved.

The CPU can detect the moving distance of the carriage 5 with an accuracy of 1/360 inch pitch by an encoder (not shown) provided on the guide shaft 6A. The position can be detected by providing an encoder on a carriage motor shaft (not shown).

A pair of conveying rollers 9A and 9B parallel to the guide shafts 6A and 6B convey the recording paper 10 as a recording medium in the direction of arrow A. With the above configuration, the inkjet recording heads 1, 2, 3, and 4 are accompanied by the scanning of the carriage 5.
The ink of each color is ejected to the portion of the recording paper 10 facing the nozzles, and the recording paper 10 is conveyed in the direction of the arrow 10 for a distance corresponding to 60 nozzle pitches each time the carriage 5 scans. It is possible to record in color.

The moving coil 12, which is applied to a microphone or the like, is used as an impact detection means in this embodiment. The shield member 11 shields a part of the ink droplets from flying to the moving coil 12. The cylindrical section of the moving coil 12 has the structure shown in FIG. 2, and the coil 12B is wound around the cylindrical portion of the movable member 12A that can vibrate in the direction of arrow a.
A fixed magnetic body 12C having a cylindrical groove sandwiching the coil 12B is magnetized so that the inner side of the coil is an S pole and the outer side is an N pole. When ink droplets land on the movable member 12A, the impact causes the movable member 12A to vibrate in the direction of arrow a, causing the coil 12B to cross the magnetic field formed by the fixed magnetic body 12C. As a result, both electrodes 12D of the coil 12B,
An induced electromotive force is generated in 12E. Impact detection is performed based on the presence or absence of this induced electromotive force.

An example of means for detecting the presence or absence of induced electromotive force is shown in FIG. The voltage of the induced electromotive force is amplified by the AC amplifier 20, its output is rectified by the rectifier 21, and the clamper 22 shapes 2.5V or more to 5V and less than that to 0V. The output is input to the S terminal of the RS flip-flop 23. The R terminal of the RS flip-flop 23 is connected to the RS out port of a CPU (not shown) that controls the device.
The output terminals of the flip-flops 23 are respectively connected to the imports. With the above configuration, if an ink droplet lands on the moving coil 12, the RS flip-flop 2
3 output is set. After the CPU recognizes them from the import, the output of the RS flip-flop 23 is reset at the out port to prepare for the next impact.

A method of measuring the mounting position deviation of the ink jet recording head 1 in the nozzle scanning direction using this apparatus will be described.

The ink jet recording head 1 is a shielding member 1.
The carriage 5 is moved so as to be in a position facing 1. An enlarged view of the positional relationship is shown in FIG. First, an ink droplet is ejected from an upper end nozzle (not shown) of the inkjet recording head 1, and the CPU moves the movable member 1 as a landing detection means.
The presence or absence of impact is detected at 2A. In this case, the ink droplet is shielded by the shield member 11 and does not land on the movable member 12A. Next, the carriage 5 is slightly moved, and then ink droplets are ejected. The CPU detects whether or not the movable member 12A has landed. Similarly, it does not detect. When the carriage 5 is sequentially moved to detect the presence / absence of impact, the CP is detected when the impact is detected.
U stores the carriage position at that time and ends.

The attachment position deviation of the ink jet recording heads 2, 3 and 4 in the scanning direction is also measured by the same method as that of the ink jet recording head 1.

In this way, the relative positions of the respective ink jet recording heads 1, 2, 3, 4 are clarified and C
When printing is performed by scanning the carriage 5, the PU causes ink droplets to land at the same position no matter how much the ink jet recording heads 1, 2, 3, 4 are driven on the time axis, and there is no color misregistration. It is possible to easily understand whether color recording is possible.

Although the moving coil is used in this embodiment, the same effect can be obtained by using a moving magnet, a piezoelectric element or the like.

In the first embodiment, the displacement of each of the ink jet recording heads 1, 2, 3 and 4 with respect to the scanning direction is detected by the ink droplets ejected from a specific nozzle.

However, this method is premised on that the nozzle array of each recording head is perpendicular to the scanning direction, and if each nozzle array has an inclination (azimuth shift) with respect to the scanning direction, The position of each nozzle on the same inkjet recording head in the scanning direction is not constant. Therefore, the landing positions of the nozzles are different from each other.

This point is improved in the second embodiment of the present invention.

First, ink droplets are ejected from the upper end nozzle of the ink jet recording head 1 in the first embodiment, and the presence / absence of landing is detected by the landing detection means. Next, ink droplets are ejected from the lower end nozzle to detect landing. In this way, the carriage 5 is moved while alternately ejecting from the upper end nozzle and the lower end nozzle, and this operation is continued until landing from both nozzles is detected. The CPU stores the carriage position at which each ink drop has landed through the shield. If there is a difference between these two detection positions, the difference between the landing positions of the ink droplets due to the azimuth shift can be suppressed by setting the nozzle position in the middle thereof.

When higher accuracy is required, a plurality of nozzle positions between the nozzles are obtained by linear interpolation from the difference between the two points and the distance in the nozzle arrangement direction, and the drive timing of each nozzle is determined. It is also possible to set it independently.

In the present embodiment, this operation is performed for the ink jet recording heads 1, 2, 3, 4 to detect the positional deviation of the ink jet recording heads 1, 2, 3, 4 with respect to the scanning direction and at the same time detect the inclination. It will be possible.

The present invention is particularly effective in an ink jet recording head and a recording apparatus for recording by forming flying droplets by utilizing thermal energy among the ink jet recording systems.

Regarding the typical structure and principle thereof, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal transducer arranged corresponding to the sheet or liquid path in which is stored, a rapid temperature increase corresponding to the recorded information and exceeding nucleate boiling is applied. , It is effective because it generates heat energy in the electrothermal converter and causes film boiling on the heat-acting surface of the recording head, resulting in the formation of bubbles in the liquid (ink) corresponding to this drive signal one-to-one. Is. Liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. The present invention also includes a configuration using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which a heat acting portion is arranged in a bending region.

In addition, JP-A-59-123670 discloses a structure in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and a pressure wave of thermal energy is absorbed. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration in which an opening corresponds to a discharge portion.

Further, a full line type recording head having a length corresponding to the width of the maximum recording medium which can be recorded by the recording apparatus is formed by combining a plurality of recording heads as disclosed in the above-mentioned specification. The present invention can exert the above-mentioned effects more effectively, although it may have a configuration that satisfies the above requirements or a configuration as one recording head integrally formed.

In addition, by being mounted on the apparatus main body, it can be electrically connected to the apparatus main body and can be supplied with ink from the apparatus main body by a replaceable chip type recording head or the recording head itself. The present invention is also effective when a cartridge-type recording head provided with an ink tank is used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a constitution of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized. If these are specifically mentioned,
Capping means, cleaning means, pressurizing or sucking means for the recording head, preheating means using an electrothermal converter or another heating element or a combination thereof, and a preliminary ejection mode for performing ejection other than recording It is also effective to perform stable recording.

Further, as the recording mode of the recording apparatus, not only the mainstream color such as black is recorded but also the recording head may be integrally formed or a plurality of them may be combined. Alternatively, the present invention is extremely effective for an apparatus provided with at least one of full colors by color mixing.

In the embodiments of the present invention described above, the ink is described as a liquid, but the ink solidifies at room temperature or lower and softens at room temperature, or is a liquid, or the above-mentioned. In the inkjet method, the temperature of the ink itself is generally adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is within a stable ejection range. Any liquid may be used.

In addition, the temperature rise due to thermal energy is positively prevented by being used as energy for changing the state of the ink from the solid state to the liquid state, or the ink is solidified in a standing state for the purpose of preventing evaporation of the ink. In some cases, whether ink is used, the ink is liquefied by application of thermal energy according to the recording signal and ejected as a liquid ink, or the one that has already started to solidify when it reaches the recording medium. The use of an ink that has the property of liquefying only by heat energy is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or JP-A No. 60-71260, a mode in which it faces the electrothermal converter in a state of being held as a liquid or solid in the recess or through hole of the porous sheet. May be 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, as a form of the recording apparatus according to the present invention, in addition to one provided integrally or separately as an image output terminal of information processing equipment such as a word processor or a computer, a copying apparatus combined with a reader or the like, May take the form of a facsimile device having a transmission / reception function.

[0045]

As described above, according to the present invention, the inclination of the inkjet recording head can be easily detected by measuring the landing position of the inkjet recording head in the scanning direction.

Further, when a plurality of ink jet recording heads are provided, the displacement of each ink jet recording head can be easily detected.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part showing a first embodiment of an inkjet recording apparatus of the present invention.

FIG. 2 is a sectional view of a moving coil according to this embodiment.

FIG. 3 is a block diagram of landing detection means in the present embodiment.

FIG. 4 is a diagram showing a positional relationship when measuring a mounting position deviation in the present embodiment.

[Explanation of symbols]

 1, 2, 3, 4 Inkjet recording head 5 Carriage 6A, 6B Guide shaft 7A, 7B, 7C, 7D Ink supply tube 8 Flexible cable 9A, 9B Roller pair 11 Shielding member 12 Moving coil 12A Moving member 12B Coil 12C Fixed magnetic material 12D, 12E electrode 20 AC amplifier 21 Rectifier 22 Clamp device 23 RS flip-flop

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B41J 25/34 9012-2C B41J 3/04 104 K 25/28 Z

Claims (5)

[Claims] 1. An ink jet recording head having a plurality of nozzles, a scanning unit for relatively scanning the ink jet recording head and a recording medium in a direction perpendicular to an arrangement direction of the plurality of nozzles, and the ink is ejected from the ink jet recording head. A plurality of nozzles are provided between the ink jet recording head and the landing detection means, a landing detection means for detecting the presence or absence of landing of ink droplets, a moving means for relatively moving the ink jet recording head and the landing detection means. An ink jet recording apparatus comprising: a shielding unit that shields a part of a plurality of ink droplets from the ink droplets to the landing detection unit. 2. The ink jet recording apparatus according to claim 1, wherein at least a part of a boundary line between the blocking and non-blocking of the blocking means is parallel to the nozzle array direction. 3. A plurality of ink jet recording heads dedicated to each of a plurality of colors are provided.
Alternatively, the inkjet recording device according to the item 2. 4. The ink jet recording head is a full line type in which ejection openings are formed over the maximum recording width of a recording medium.
The inkjet recording device according to item 1. 5. The ink jet recording head is provided with an electrothermal converter for generating thermal energy for ejecting ink, wherein the electrothermal converter is provided.
The inkjet recording device according to item 1.