JP2001334641A - Method for adjusting recording head, and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust a recording head accurately and easily after replacement when an ink jet recorder comprises a plurality of independently replaceable recording heads. SOLUTION: The ink jet recorder comprises a plurality of independently replaceable recording heads each of which performs recording by sticking ink liquid drops of a plurality of recording colors onto a recording medium. The ink jet recorder further comprises a control means 22 which shifts the timing of outputting ink liquid drops from each recording head depending on the positional shift of each recording head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head adjustment method and an ink jet recording apparatus for performing recording by adhering dots of ink droplets on a recording medium, and to a method for eliminating positional deviation between a plurality of recording heads.

[0002]

2. Description of the Related Art In recent years, ink-jet recording apparatuses have rapidly become widespread as output apparatuses for industrial use, office use, and personal use because of easy colorization of digital images.

A plurality of independently replaceable recording heads are provided for performing color image recording by depositing dots of ink droplets of a plurality of recording colors on a recording medium in accordance with image data corresponding to a plurality of recording colors. Ink-jet recording apparatuses equipped with a printer have also become widespread.

[0004]

By the way, in an ink jet recording apparatus provided with a plurality of independently replaceable recording heads for recording by depositing dots of ink droplets of a plurality of colors on a recording medium, for some reason. In some cases, it is necessary to replace one of the recording heads.

[0005] With regard to such exchange of the recording head, if only the recording head of any recording color is exchanged, a delicate displacement occurs between the exchanged recording head and another unexchanged recording head. And adversely affect the image quality. Therefore, it is necessary to adjust the positions of the recording heads.

As such a position adjustment, it is conceivable to mechanically adjust the recording head using an actuator or the like in accordance with the amount of displacement detected from the adjustment chart. However, when such an adjustment mechanism is provided, there is a problem that the inkjet recording apparatus becomes complicated and expensive.

As another method of such position adjustment, a nozzle (recording head is moved in the sub-scanning direction) used to form the same dot on the recording medium in accordance with the amount of displacement detected from the adjustment chart. There is a method of changing the plurality of ink discharge nozzles included in the printer.

With such position adjustment, it is possible to cope only with a position shift in the sub-scanning direction. In addition, there is a problem that only a shift amount can be corrected according to the arrangement pitch of the nozzles.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a recording head adjustment method and an ink jet method that can accurately and easily perform adjustment after replacing a recording head when a plurality of independently replaceable recording heads are provided. It is intended to realize a recording device.

[0010]

Means for Solving the Problems The inventors of the present application have:
As a result of intensive research on adjustment after replacing the printhead when multiple independently replaceable printheads are provided, it is newly found that adjustment can be performed accurately and easily using a method different from the conventional change of nozzles used. Was.

Therefore, the above-mentioned object is achieved by the following inventions. According to a first aspect of the present invention, there is provided a recording head for an inkjet recording apparatus including a plurality of independently replaceable recording heads for performing recording by attaching dots of ink droplets of a plurality of recording colors on a recording medium. An adjustment method, wherein an output timing of ink droplets from each recording head is shifted according to a positional shift of each recording head.

According to a fifth aspect of the present invention, there is provided an ink jet recording apparatus having a plurality of independently replaceable recording heads for recording by depositing dots of ink droplets of a plurality of recording colors on a recording medium. An ink jet recording apparatus comprising a control means for shifting the output timing of ink droplets from each recording head according to the displacement of each recording head.

In these inventions, the positional shift of each recording head is eliminated by shifting the output timing of the ink droplets from each recording head. As a result, accurate adjustment can be performed at a finer pitch than the conventional change of the ink discharge nozzle.

(2) The recording head according to the first aspect, wherein the output timing of the ink droplets from each recording head is shifted based on the output result of the adjustment chart. This is the adjustment method.

Further, according to a sixth aspect of the present invention, the control means has a function of outputting an adjustment chart and a function of outputting from the respective recording heads in accordance with a correction value inputted based on an output result of the adjustment chart. The inkjet recording apparatus according to claim 5, further comprising: a function of shifting an output timing of the ink droplet.

In these inventions, by shifting the output timing of the ink droplets from each recording head in accordance with the correction value input based on the output result of the predetermined adjustment chart, the positional deviation of each recording head can be reduced. It is possible to resolve it accurately.

(3) According to the third aspect of the present invention, in order to shift the output timing of ink droplets from each recording head,
3. The printhead adjusting method according to claim 2, wherein blank data is inserted at the head of the image data according to the amount of shift for the image data of each recording color stored in the image memory.

According to a ninth aspect of the present invention, the control means shifts the output timing of the ink droplets from each recording head with respect to the image data of each color stored in the image memory. 9. The ink jet recording apparatus according to claim 5, wherein blank data is inserted at the head of the image data according to the amount.

In these inventions, by shifting the output timing of the ink droplets from each recording head in accordance with the blank data inserted into the image data in the image memory, the positional deviation of each recording head can be accurately eliminated. It becomes possible.

(4) According to the invention described in claim 4, in order to shift the output timing of the ink droplets from each recording head,
3. The printhead adjusting method according to claim 2, wherein the readout timing of the image data of each recording color stored in the image memory is changed.

According to a tenth aspect of the present invention, the control means changes the read timing of the image data of each color stored in the image memory in order to shift the output timing of the ink droplet from each recording head. An ink jet recording apparatus according to any one of claims 5 to 8, wherein

In these inventions, by shifting the output timing of the ink droplets from each recording head by adjusting the timing of reading the image data from the image memory, it is possible to accurately eliminate the positional deviation of each recording head. Will be possible.

(5) It is desirable to provide an image memory for storing image data, and to start outputting ink droplets after storing image data for at least one scan in the main scanning direction.

(6) Preferably, the image memory has an area for each recording color. (7) The control means shifts the output timing of the ink droplets from each recording head in accordance with at least one of the displacement of the recording head in the main scanning direction and the displacement of the recording head in the sub-scanning direction. Accordingly, it is possible to cope with the positional deviation of the recording head between the main scanning direction and the sub-scanning direction.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an ink jet recording apparatus used in the present embodiment.

RGB data or L supplied from outside
The ab data is subjected to predetermined color conversion or color separation in a color conversion processing unit 30 in the inkjet recording device 20, and is further subjected to error diffusion processing in an error diffusion processing unit 40.
Next, the data conversion unit 50 converts the data into image data for image formation in the printer, and the image data is recorded in the image memory 60. The output unit 70 having a plurality of independently replaceable recording heads for performing recording by attaching dots of ink droplets of a plurality of recording colors to the recording medium performs printing on the recording medium 80. And image recording is performed.

In response to an instruction such as a numerical value (correction value) input from the operation display unit 21, the control unit 22 controls a plurality of recordings of each color ink arranged in the output unit 70 in accordance with the input correction value. Control is performed to shift the output timing of the ink droplets from the head.

The control for shifting the output timing of the ink droplets of each color ink from the plurality of recording heads is as follows: blank image data for each recording color stored in the image memory is changed according to the shift amount; The timing at which each recording head ejects each ink while moving in the main scanning direction, by either inserting at the beginning of the image data or changing the readout timing of the image data of each recording color stored in the image memory. Is realized by electrically controlling

The ink jet recording apparatus 20 outputs an adjustment chart for adjusting a recording head on a recording medium based on data from a chart data holding unit 23 which holds pattern data of the adjustment chart. Is configured to be possible.

Output unit 70 of ink jet recording apparatus 20
Include, as basic colors, cyan ink (hereinafter “C ink”), magenta ink (hereinafter “M ink”), yellow ink (hereinafter “Y ink”), and black dark ink (hereinafter “K ink”). The description will be made assuming that it is provided.

FIG. 2 schematically shows the structure of a carriage 71 provided in the output unit 70 and moving in the main scanning direction during image formation. Here, the carriage 71 includes a Y ink recording head 710Y and an M ink recording head 710.
The M, C ink recording head 710C, and the K ink recording head 710K are provided so as to be independently replaceable.

FIG. 3 is a perspective view showing the recording heads 710Y to 710K of the carriage 71 of FIG. 2 described above. Cables 711Y to 711K for supplying drive signals to the recording heads are respectively connected. . Also,
Similarly, each recording head has an ink supply pipe 7 for supplying ink of each color from an ink tank (not shown).
12Y to 712K are provided. Here, for the sake of explanation, only the ink supply pipe 712Y is shown.

Further, a lever 713 for detachably holding each recording head is provided. In this FIG.
For explanation, only the lever 713Y is shown. Although not shown in detail in FIG. 3, the carriage 71 is provided with grooves and irregularities for mounting each recording head, and the recording heads are mounted at predetermined positions on the grooves and irregularities. Then, it is fixed by the lever 713.
When replacing any of the recording heads, the operation may be performed in the direction of the arrow of the head removal direction in FIG. 3 with the lever operated in the release direction. In addition, a mechanism for fixing,
The removal direction and the like are merely examples, and are not limited to those shown here as long as they can be detached independently.

Further, in addition to the above-described basic color having the normal density, a special color or a light color ink may be combined, but the description thereof will be omitted. Hereinafter, an operation (a print head adjusting method) of the ink jet printing apparatus of the present embodiment will be described. Here, a case will be described as an example in which the positional deviation caused when any one of the recording heads is replaced is adjusted.

First, the ink jet recording apparatus 20 is set in the operating state, the mode is changed from the operation display section 21, and the user performs an operation to enter the head replacement mode (S1 in FIG. 4). With this operation input, the control unit 22 operates the inkjet recording device 20 in the head replacement mode.

Thereafter, the power of the ink jet recording apparatus 20 is turned off under the control of the control unit 22 or the operation of the user. In this power-off state, the user replaces any desired recording head (see FIG. 3) (S2 in FIG. 4).
At this time, first, the carriage 71 is moved to a predetermined replaceable position, a cover (not shown) is opened, and the cable 71 is opened.
1, the lever 713 is released, and the old recording head is removed. Then, a new recording head of the same color ink is prepared, the cap or tape for protecting the head surface is removed, the recording head is inserted at the original position, the cable 711 is connected, and the recording head 710 is fixed with the lever 713. Then, the cover (not shown) is closed, and the power of the inkjet recording apparatus 20 is turned on.

Thereafter, the ink jet recording apparatus 20 continues the head replacement mode under the control of the control unit 22 or the operation of the user. Here, the control unit 22 automatically detects which color the replaced recording head is in, or the user inputs the color according to a display menu of the operation display unit 21. Then, the ink is distributed to the replaced recording head, and cleaning is performed to check whether there is any abnormality in the ejection of the ink droplets (S3 in FIG. 4). If no abnormality is found in the test print created by this cleaning, the process proceeds to the next step. If an abnormality is found, the cleaning is repeated by the user inputting on the operation display unit 21.

Next, the control section 22 adjusts the exchanged recording head on the recording medium 80 based on the data of the adjustment chart pattern held in the chart data holding section 23. Is output.

In this adjustment chart, a print head of any color is determined as a "reference print head", and an adjustment for detecting a color shift between the reference print head and another print head is performed. Output chart.

Here, when black is used as a plurality of color inks, it is desirable to adjust another print head using the print head using black ink as a reference print head.

As the adjustment chart, for example,
The one shown in FIG. 5 can be used. The example of FIG. 5 is an example of an adjustment chart for detecting a positional shift between three colors of YMC and K. Here, a solid line is a line printed by a reference recording head, and a broken line is a line printed by a recording head of each color.

For this reason, when a plurality of ink ejection nozzles are present in each recording head, ink droplets are ejected from the ink ejection nozzle corresponding to the same position while changing the timing in the sub-scanning direction. Thus, lines of Y and K, M and K, and C and K are formed in the main scanning direction. Or
When a plurality of ink ejection nozzles are present in each recording head, ink droplets are ejected from ink ejection nozzles corresponding to different positions in the sub-scanning direction, and Y and K, M, and K in the main scanning direction. , C and K lines are formed.

In the case of FIG. 5, 7 from -3 to 0 to +3 is used.
The timing of the stage or the nozzle is changed to form the above-described adjustment chart. In the example of FIG. 5, since Y and K and C and K coincide with each other at the position of 0 and the adjustment charts match, it shows a state in which no displacement has occurred. In addition, since the adjustment charts at M and K coincide with each other at the position of −1, a state is shown in which the M print head is misaligned.

FIG. 6 schematically shows the state of the recording head in which the displacement shown in FIG. 5 has been detected in the adjustment chart. This figure 6
(A) shows a recording head 710Y for simplifying the description.
It is assumed that one ejection nozzle (circular portion) exists in the recording head 710K. Also, the recording head 71
It is assumed that the position shift of 0M is shifted by one dot to the rear side in the sub-scanning direction.

In the case of the adjustment chart of FIG. 5, the exchanged recording is performed by inputting “0”, “−1”, and “0” as correction values from the operation input unit 21 (S5 in FIG. 4). "Timing correction value" for eliminating head misalignment
Is found.

Then, the control unit 22 writes the input correction value in a nonvolatile memory or the like, and performs control so that the correction value is used as a timing correction value in the future image formation (FIG. 4S).
6). Thereafter, the inkjet recording apparatus 20 ends the head replacement mode under the control of the control unit 22 or the operation of the user.

Then, in the image formation after the completion of the head replacement mode, the control unit 22 executes control to shift the output timing of the ink droplets from the recording head 710M by referring to the correction value. Ink ejection is performed so as to eliminate the positional deviation of the ink droplets.

In this embodiment, the recording head 710
Since M is shifted one dot behind the other print heads in the sub-scanning direction, the print head 710M delays the timing of ink ejection by one line from the other print heads to achieve color It is possible to form an image without displacement.

For this purpose, blank data for shifting the ink ejection timing in the direction of delaying the ink ejection timing is inserted at the head of the image data by the amount corresponding to M with respect to the image data stored in the image memory 60. FIG.
(B) to (e) schematically show the state of YMCK image data in each color area of the image memory 22.
Here, the contents of the image data are schematically shown, such as AAAAA for the first main scanning line, BBBB for the second main scanning line, and CCCC for the third main scanning line. The image data of each color is stored in different areas of the same memory element,
Alternatively, they are stored on different memory elements.

Here, as described above, in order to delay the timing, blank data for one main scanning line for M (here, “0” is shown as an example, and data that does not perform ink ejection is shown here). ) Is inserted. If the shift direction of M is reversed, a similar operation can be realized by inserting blank data into other YCK image data. By inserting blank data into image data in this manner, it is possible to shift the output timing of ink droplets from the recording head. Also, here, one dot (1
In the example described above, a shift of (line) is provided, but blank data may be inserted according to the shift amount.

Also, instead of inserting blank data as shown in FIG. 6D, the image data of each color is set to be the same, and only the image data corresponding to M is ejected according to the above-mentioned correction value. An address control unit (not shown) may change the read timing of the M image data in the direction of delaying the timing in accordance with an instruction from the control unit 22. If the shift direction of M is opposite, the read timing of M may be advanced earlier than the others. By changing the read timing of the image data in this manner, it is possible to shift the output timing of the ink droplets from the recording head. Also, here, an example is described in which a shift of one dot (one line) is provided in the sub-scanning direction, but the read timing may be changed according to the shift amount. In this case, the ink ejection may be started in a state where all the image data is stored in the image memory, but the ink discharge may be started when the image data of at least one line is completed.

In the above description, the adjustment is performed in accordance with the displacement of the recording head in the sub-scanning direction. Thus, the same adjustment can be performed.

<Other Embodiments> In the above embodiment, the operation for adjusting the positional deviation at the time of exchanging the recording head has been described. It is also possible to perform only the positional deviation adjustment when the use time elapses or the user desires).

<Other Embodiments> When the ink ejection timing is changed due to the change of the blank data insertion or readout timing, the order of superimposition of the inks on the recording medium is changed. For example, if there is no misalignment of the recording head, the inks overlap in the order of YMCK, but in the case of the misalignment shown in FIG.
The inks overlap in the order of CKM. Further, if M is shifted in the opposite direction to FIG. 6A, the inks overlap in the order of MYCK.

Therefore, a positional deviation is intentionally generated in the recording head by an actuator (not shown) or the like, and the above-described ink ejection timing adjustment is performed, so that the ink superimposing order on the recording medium is intentionally adjusted. It can be changed. By changing the ink superposition order in this way, it is possible to control the color tone,
The advantage that arises.

[0056]

As described above, by using the recording head adjusting method and the ink jet recording apparatus of the present invention,
When a plurality of independently replaceable recording heads are provided, the positional deviation of the recording heads can be accurately and easily adjusted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state of a recording head used in an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a state of a recording head used in the embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an adjustment chart used in the embodiment of the present invention.

FIG. 6 is an explanatory diagram schematically showing a position shift and a state of image data on a memory in the operation of the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 20 inkjet recording device 21 operation display unit 22 control unit 23 chart data holding unit 30 color conversion processing unit 40 error diffusion processing unit 50 printer data conversion unit 60 image memory 70 output unit

Claims (11)

[Claims] 1. A recording head adjusting method for an ink jet recording apparatus comprising a plurality of independently replaceable recording heads for performing recording by attaching dots of ink droplets of a plurality of recording colors on a recording medium, A printhead adjustment method, wherein the output timing of ink droplets from each printhead is shifted according to the positional shift of each printhead. 2. Based on the output result of the adjustment chart,
2. The printhead adjusting method according to claim 1, wherein the output timing of the ink droplets from each printhead is shifted. 3. In order to shift the output timing of ink droplets from each recording head, blank data is added to image data of each recording color stored in an image memory in accordance with the amount of shifting, at the beginning of the image data. 3. The recording head adjusting method according to claim 2, wherein the recording head is inserted into the recording head. 4. The read-out timing of image data of each recording color stored in an image memory in order to shift the output timing of ink droplets from each recording head. Print head adjustment method. 5. An ink jet recording apparatus comprising a plurality of independently replaceable recording heads for performing recording by depositing dots of ink droplets of a plurality of recording colors on a recording medium, wherein the position of each recording head is determined. An ink jet recording apparatus, comprising: a control unit that shifts an output timing of an ink droplet from each recording head according to the displacement. 6. The control unit shifts an output timing of an ink droplet from each recording head according to a function of outputting an adjustment chart and a correction value input based on an output result of the adjustment chart. The ink jet recording apparatus according to claim 5, comprising: a function. 7. An image memory for storing image data, wherein output of ink droplets is started after storing image data for at least one scan in the main scanning direction. Item 7. An ink jet recording apparatus according to any one of Items 6. 8. The ink jet recording apparatus according to claim 5, wherein said image memory has an area for each recording color. 9. The image processing apparatus according to claim 1, wherein the control unit shifts the output timing of the ink droplets from each recording head to blank image data in accordance with the shift amount with respect to the image data of each color stored in the image memory. 9. The ink jet recording apparatus according to claim 5, wherein the data is inserted at the head of data. 10. The apparatus according to claim 1, wherein the control unit changes the read timing of the image data of each color stored in the image memory in order to shift the output timing of the ink droplet from each print head. An inkjet recording apparatus according to any one of claims 5 to 8. 11. The control unit shifts the output timing of the ink droplets from each recording head according to at least one of the displacement of the recording head in the main scanning direction and the displacement of the recording head in the sub-scanning direction. The inkjet recording apparatus according to any one of claims 5 to 10, wherein: