JP2000062148A - Image recorder and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control ink ejection time so that fluctuation at the time of manufacturing head supporting mechanism, or the like, is absorbed by delaying the ink ejection time of each nozzle so that positional shift of the nozzle is offset. SOLUTION: Image data for each bit being imparted to each nozzle is delayed by a specified time by a delay circuit 20 of an image data control circuit 15 before being delivered to a head drive circuit 12. The specified time is suitable for correcting the difference between actual recording results and ideal recording results and it can be calculated by reading out the actual recording results by means of an image reader, e.g. a scanner, and comparing it with the ideal recording results. When the maximum delay is set at a large level, relatively large distortion in the linearity of head or so-called kink of each nozzle can be corrected. Since the output timing of image data can be controlled not mechanically but through an electric delay circuit, image recording quality can be enhanced without increasing the number of parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus and an image recording method for correcting a print position deviation when recording an image of a single color or a plurality of colors using a single or plural long heads.

[0002]

2. Description of the Related Art Long recording head (hereinafter, long head)
In the case of several hundred ink ejection nozzles per inch, a total of several thousand ink ejection nozzles are formed in the direction perpendicular to the recording paper conveyance direction. In an image recording apparatus such as a printer using this long head, while conveying the recording paper, ink is ejected from the ink ejection nozzles of the long head onto the recording paper to form an image.

Further, in an image recording apparatus using a long head, it has been known that the deviation of the ink ejection position occurs due to the following factors. That is, the positional deviation of the recording position along the recording paper conveyance direction is (1) variation in the ink ejection direction from the nozzle (2) variation in the ink ejection speed from the nozzle (3) variation in the linearity of the head (4) Changes in head linearity due to thermal expansion and contraction of the head (5) Variations in mounting position of the head (6) Changes in head mounting position due to thermal expansion and contraction of the head support member (7) Fluctuations in sheet conveyance speed it is conceivable that.

Further, the positional deviation of the recording position along the nozzle row direction is (1) variation in the ink ejection direction from the nozzles (5) variation in the mounting position of the head (8) extension of the total head length due to thermal expansion and contraction of the head Contraction (6) It is considered that the change in the head mounting position due to thermal expansion and contraction of the head support member is a factor.

In the conventional image recording apparatus, the factors (1) to (3) relating to the head among the above factors depend on the quality improvement in the manufacturing process of the head.

Further, the factors (4) and (8) have kept their effects to a minimum by keeping the temperature of the head constant.

Factor (5) related to the main body of the apparatus has been minimized by increasing mechanical dimensional accuracy.

The factor (6) has minimized its influence by promoting heat dissipation and using a material having a low coefficient of thermal expansion.

The factor (7) is to minimize its influence by improving the mechanism control accuracy such as suppressing the variation in the conveying speed of the recording paper.

[0010]

With respect to the factors (1) to (4) and (8) which these prior arts have, the following technical points are taken when trying to maintain and enhance the image quality by improving the head. , There are financial problems. That is, (i)
The quality requirement for the head becomes high, which hinders the improvement of the production yield of the head (ii) and the cost reduction of the head (iii).

Regarding the factors (5) and (6), if the mechanical dimensional accuracy of the member supporting the head is increased or the mechanical material is improved so as to maintain or increase the accuracy, the following technical points are required. There are financial problems. That is, (i
v) The quality requirement for the head support mechanism becomes high, (v) the improvement of the production yield of the head support mechanism is hindered, and (vi)
This hinders cost reduction of the head support mechanism.

The present invention has been made in view of the above problems, and an object thereof is to provide an image recording apparatus and an image recording method capable of controlling ink ejection timing so as to absorb variations in manufacturing of heads, head support mechanisms, and the like. It is to be.

[0013]

In order to solve the above problems and achieve the object, the image recording apparatus of the present invention has the following constitution. That is, a recording head in which a plurality of ink ejection nozzles are arranged in a line, a nozzle drive unit that ejects ink from the nozzles according to image data, and a recording medium is conveyed to the nozzle drive unit at a predetermined speed. In an image recording apparatus having a conveyance unit and a control unit that controls the operation timing of each unit, an ink ejection timing delay unit that delays the ink ejection timing of each nozzle so as to cancel the positional deviation of the nozzle. Provided.

The image recording method of the present invention has the following features. That is, a recording head in which a plurality of ink ejection nozzles are arranged in a line, a nozzle drive unit that ejects ink from the nozzles according to image data, and a recording medium is conveyed to the nozzle drive unit at a predetermined speed. In an image recording apparatus having a conveyance means and a control means for controlling the operation timing of each means, the ink ejection timing for each nozzle is delayed so as to cancel the positional deviation of the nozzle.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The first to third embodiments of the present invention will be described below.
Embodiments will be described in detail with reference to the accompanying drawings.

In the first embodiment, a method of delaying the drive timing for each nozzle regardless of the image data management mode will be described.

Further, in the second embodiment, when image data is managed for each raster in the nozzle row direction (hereinafter referred to as horizontal raster), a single raster is selected from a plurality of horizontal rasters as image data for each nozzle. A method of enabling selection will be described.

Further, in the third embodiment, when the image data is managed for each raster (hereinafter referred to as a vertical raster) in the recording paper conveyance direction, the drive timing is delayed for each nozzle and the image data for each nozzle is delayed. As a first method, a single raster can be selected from a plurality of vertical rasters, various logical operations between adjacent rasters are possible, and image data for each nozzle is shifted in bit units. [First Embodiment] The image recording apparatus according to the first embodiment is
When managing the image data as raster data along the nozzle row direction, it has a function of delaying the ink ejection timing independently for each nozzle in the recording paper conveyance direction.

The variable range of the delay amount and the maximum delay amount may be determined in consideration of the balance of the actual size of the head or the main body device and the effect of improving the recorded image.

In this embodiment, since only the delay amount is changed, the adjustment width and the adjustment range are limited only by the circuit scale. Therefore, it is possible to flexibly respond to the performance required for an actual device. [Hardware Configuration of Image Recording Apparatus] FIG. 1 is a hardware configuration diagram of the image recording apparatus of the first embodiment.

In FIG. 1, the image recording apparatus of this embodiment is provided with a long head, a recording paper conveying mechanism and an ink supplying mechanism as mechanical hardware.

The long head is provided for each color of Y, M, C, and K, and a total of several thousand ink ejection nozzles are linearly integrally formed at a rate of several hundred per inch. There is.

The recording paper conveyance mechanism is composed of a motor 8, a motor belt 9, a belt pulley 10 and a recording paper conveyance belt 11, and the recording paper conveyance belt 11 is driven by the driving force of the motor 8 transmitted through the motor belt 9. The recording paper 14 is moved at a predetermined speed in the recording paper conveyance direction.

The ink supply mechanism is composed of ink tanks 16 for accumulating the inks of the colors corresponding to the long heads of the respective colors. The ink tanks 16 of the respective colors are mounted on the long heads of the corresponding colors, and the long heads The ink of the color corresponding to is supplied.

Further, the image recording apparatus of this embodiment comprises an image data control circuit 15, a head drive circuit 12, and a motor drive circuit 7 as electrical hardware.

The image data control circuit 15 has a delay circuit 20 for delaying the ejection timing for each nozzle as shown in FIG.

The head drive circuit 12 applies image data to the head 13. The motor drive circuit 7 drives the motor 8 at a timing corresponding to the ink ejection timing of the head 13.
To drive.

Motor drive circuit 7 and recording data control circuit 1
The entire device including 5 is centrally controlled by the system controller.

The system controller includes a microcomputer 1 as a central processing unit, a ROM 2 for storing operation control programs, a RAM 3 for temporarily storing image data and operation control programs, image data and An NVRAM 6 that holds other data, a sensor that detects the recording paper conveyance position and the head position, an arithmetic processing circuit that takes in a detection signal from the sensor and gives a control signal to the motor drive circuit 7 and the image data control circuit 15. 4. An interface circuit 5 with an external device or a peripheral circuit is provided. [Operation of First Embodiment] FIG. 2 is a diagram showing an operation of the delay circuit 20.

As shown in FIG. 2, the image data for each bit given to each nozzle is delayed by a delay circuit 20 of the image data control circuit 15 for a predetermined time and output to the head drive circuit 12.

The predetermined time is a value suitable for correcting the difference between the actual recording result and the ideal recording result, and the actual recording result is read by an image reading device such as a scanner.
It can be calculated by comparing with the ideal recording result.

Further, if the maximum delay amount is set to a large value, it is possible to correct a relatively large distortion of head linearity and so-called deviation for each nozzle. [Effects of the First Embodiment] In the first embodiment, the output timing of the image data can be controlled by the electrical delay circuit without controlling the ink ejection timing of the head due to the mechanical structure. The quality of image recording can be improved without increasing.

Further, since the precision required for the mechanical structure can be relaxed, the cost can be reduced.

The image recording apparatus according to the present embodiment can independently select a raster for each nozzle in the recording paper conveyance direction when managing image data as raster data in the nozzle row direction.

The maximum front-rear width of the raster that can be selected may be determined in consideration of the balance of the actual size of the head and the main unit and the effect of improving the printed image.

Further, the image recording apparatus of the present embodiment can control the deviation of the recording position to 1 dot or less for the adjustment in raster units. [Second Embodiment] FIG. 3 is a block diagram showing a raster selection circuit mounted in the image recording apparatus of the second embodiment.

In the following description, description of the same structure as the image recording apparatus of the first embodiment will be omitted, and different parts will be described.

The image data control circuit 15 shown in FIG.
A raster selection circuit 30 is provided for each nozzle as shown in FIG. [Operation of Second Embodiment] As shown in FIG. 3, each nozzle of the head is provided with image data from a single raster selected by a raster selection circuit 30 that selects a single raster from a plurality of rasters. It

The raster selection circuit 30 selects a desired raster pointer from the raster pointers 0 to n indicating the head position of the raster on the memory in accordance with the raster pointer selection signal, and at the same time, the actual recording result and the ideal recording. Select a raster suitable for correcting the difference from the result.

The selection criterion can be calculated by reading an actual recording result with an image reading device such as a scanner and comparing it with an ideal recording result.

When the selectable raster front-rear width is set large, a relatively large distortion of the head linearity and so-called deviation of each nozzle can be corrected. [Effects of Second Embodiment] In the second embodiment, the same effects as in the first embodiment can be obtained. The effects of this embodiment can be increased by configuring the first embodiment and the second embodiment in combination. [Third Embodiment] An image recording apparatus according to the third embodiment is
When managing image data as raster data in the recording paper conveyance direction, logical operation between adjacent rasters is possible, pre-computation rasters or post-computation rasters can be selected independently for each nozzle, and selected. The ink ejection timing relating to the raster data can be arbitrarily shifted within a predetermined range.

The maximum shift front / rear width of the discharge timing that can be selected may be determined in consideration of the balance of the actual size of the head and the main body apparatus and the effect of improving the recorded image.

Further, in the present embodiment, the deviation of the ink ejection position can be suppressed to 1 dot or less for the adjustment in the dot unit in the nozzle row direction, and the ink for the adjustment in the dot unit or less than the dot unit in the recording paper conveyance direction. Displacement of the ejection position can be suppressed to less than 1 dot. [Structure of Third Embodiment] In the following description, description of the same structure as the image recording apparatus of the first embodiment will be omitted, and different parts will be described.

The image data control circuit 15 shown in FIG. 1 includes a vertical raster selection circuit 40 and a bit operation circuit 4 as shown in FIG.
1, a data selection circuit 42, and a data delay circuit 43.

As shown in FIG. 5, the vertical raster selecting circuit 40 adds bit data 0 to 8 before addition to bit data adjacent to each other in the vertical direction.

As shown in FIG. 6, the bit operation circuit 41 selects a single bit as the post-selection data from a plurality of pre-selection data in response to the selection signal over several bits before and after the reference position. Then, after the selection, the data adjacent to the data is selected. The bit arithmetic circuit 41 is provided for each nozzle.

As shown in FIG. 7, the data selection circuit 42 selects each bit signal as pre-selection data and post-addition data in accordance with the selection signal.

The data delay circuit 43 delays the data and the shift number according to the shift clock as shown in FIG.

The data delay circuit 43 is an example using shift means among various delay circuits. [Operation of Third Embodiment] As shown in FIG. 4, in the image recording apparatus of the third embodiment, data of a single raster selected from a plurality of vertical rasters is sequentially applied to each nozzle of the head. To be done. At this time, for the data to be recorded, a single raster and its adjacent raster are selected by the vertical raster selection circuit 40, and the two selected rasters are logically ORed by the bit calculation circuit 41.

After that, the data selection circuit 42 further selects one of the selected raw raster data and logical sum data. Then, in the data delay circuit 43,
It is delayed by a predetermined time and output to the head drive circuit 12.

Here, the selection criterion for selecting a raster from a plurality of vertical rasters, the selection criterion for selecting a raw raster or a logical sum raster after selection, the delay time in the data delay circuit, etc. are the actual recording result and the ideal recording. It is an appropriate value for correcting the difference of the result.

Each standard can be calculated by reading an actual recording result with an image reading device such as a scanner and comparing it with an ideal recording result.

If the selection width of each adjustment value is set to be large, a relatively large distortion of the head linearity and so-called deviation of each nozzle can be corrected. [Effects of Third Embodiment] In the third embodiment, the first,
The same effect as that of the second embodiment can be obtained.

In the third embodiment, the vertical raster selection circuit 40, the data selection circuit 42, and the data delay circuit 43 are mainly combined, but when the actual equipment is constructed, the requirements of the equipment are required. It goes without saying that these elements can be selected according to the performance.

In the above-described embodiment, particularly in the ink jet recording system, means for generating thermal energy as energy used for ejecting ink (for example, electrothermal converter or laser light) is provided, and High density and high definition recording can be achieved by using a method in which the state of ink is changed by thermal energy.

Regarding its typical structure and principle, 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 the liquid crystal is held, which corresponds to the recorded information and gives a rapid temperature rise exceeding the film boiling. Since heat energy is generated in the electrothermal converter to cause film boiling on the heat acting surface of the recording head, air bubbles in the liquid (ink) corresponding to this drive signal in a one-to-one correspondence can be formed. It is valid. The 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 in a pulse shape, because bubbles can be grown and contracted immediately and appropriately, and thus a 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 configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations in which the heat-acting surface is arranged in a bending region. In addition, for multiple electrothermal converters,
Japanese Unexamined Patent Publication No. 59-123670, which discloses a configuration in which a common slot is used as a discharge portion of the electrothermal converter, and Japanese Patent Laid-Open No. 59-63, which discloses a configuration in which an opening for absorbing a pressure wave of thermal energy is associated with the discharge portion. A configuration based on Japanese Patent No. 138461 may be used.

Further, as a full line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length can be increased by combining a plurality of recording heads as disclosed in the above-mentioned specification. Either of the structure satisfying the requirement or the structure as one recording head integrally formed may be used.

In addition to the cartridge type recording head in which the ink tank is integrally provided in the recording head itself described in the above-mentioned embodiment, the recording head is electrically connected to the apparatus main body by being attached to the apparatus main body. A replaceable chip-type recording head that enables physical connection and ink supply from the apparatus main body may be used.

Further, it is preferable to add recovery means for the recording head, preliminary means, etc. to the structure of the recording apparatus described above because the recording operation can be made more stable. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or sucking means, electrothermal converters or heating elements other than these, or preheating means by a combination thereof. Further, provision of a preliminary ejection mode for performing ejection different from recording is also effective for stable recording.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but the recording head may be integrally formed or a plurality of combinations may be used. Alternatively, the device may be provided with at least one of full-color mixed colors.

In the above-described embodiments, the explanation is made on the assumption that the ink is a liquid. However, even if the ink is solidified at room temperature or lower, it should be softened or liquefied at room temperature. Or, in the inkjet method, it is general that the temperature of the ink itself is 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 in a stable ejection range.
It suffices that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent the temperature rise due to thermal energy from being used as the energy for changing the state of the ink from the solid state to the liquid state,
Alternatively, in order to prevent the ink from evaporating, an ink that solidifies in a standing state and liquefies by heating may be used. In any case, by applying heat energy, such as ink that is liquefied by applying heat energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In such a case, the ink is retained as a liquid or solid in the recesses or through holes of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. 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, as a form of the recording apparatus according to the present invention, in addition to the one provided integrally or separately as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and further transmission / reception It may take the form of a facsimile machine having a function.

Other Embodiments Even when the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus including one device (for example, a copying machine). Machine, facsimile machine, etc.).

Further, an object of the present invention is to supply a storage medium having a program code of software for realizing the functions of the above-described embodiment to a system or apparatus, and to supply a computer (or CPU) of the system or apparatus.
It is needless to say that it can be achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD
-R, magnetic tape, non-volatile memory card, ROM, etc. can be used.

Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) running on the computer based on the instruction of the program code. It is needless to say that this also includes a case where the above) performs a part or all of the actual processing and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that a case where the CPU or the like included in the function expansion board or the function expansion unit performs some or all of the actual processing and the processing realizes the functions of the above-described embodiments is also included.

When the present invention is applied to the above-mentioned storage medium, the storage medium stores a program code of "a step of delaying the ink ejection timing for each nozzle so as to cancel the nozzle position deviation". do it.

As described above, in the present embodiment, the factors (1) to (6) of the print position deviation in the recording paper conveyance direction can be corrected in dot units for each nozzle.

It becomes possible to make corrections in units of less than dots for each nozzle.

It is possible to perform correction for each nozzle in dot units or in units of less than dots.

Further, the factors (1) to (6) of the displacement of the print position in the nozzle row direction can be corrected in dot units for each nozzle.

It is possible to perform correction for each nozzle in dot units or in units of less than dots.

Regarding the factor (8) of the print position deviation in the nozzle row direction, it is possible to correct dot by nozzle for each nozzle as an effect of combining the first and second embodiments.

The above-described effect of improving the accuracy of the printing position is obtained.

Further, from the viewpoint of the quality of the entire image, a monochromatic recording image has an effect of improving image distortion in that the influence of a relatively gentle position variation factor in the recording paper conveyance direction can be mitigated.

Further, in a recorded image using a plurality of heads,
There is a so-called registration accuracy improving effect in a multi-head multi-color image recording apparatus that can mitigate the influence of a relatively gentle position variation factor in the recording paper conveyance direction between a plurality of heads.

As described above, not only the effect of improving the performance of the image recording apparatus can be expected, but also the great economic effect is obtained. That is, because it is solved by software or an electric circuit without depending on the mechanical dimensional accuracy of the apparatus body or quality improvement in the manufacturing process of the head, without increasing the manufacturing cost of the head or parts, The image can be improved.

Further, since there is also an effect of relaxing the accuracy required in the manufacturing process, it is possible to further reduce the cost.

[0083]

As described above, according to the present invention, it is possible to control the ink ejection timing so as to absorb the variations in manufacturing the head, the head supporting mechanism and the like.

[0084]

[Brief description of drawings]

FIG. 1 is a hardware configuration diagram of an image recording apparatus according to a first embodiment.

FIG. 2 is a diagram showing a delay circuit for each nozzle shown in FIG.

FIG. 3 is a diagram showing a horizontal raster selection circuit provided in the image recording apparatus of the second embodiment.

FIG. 4 is a diagram showing an image data control circuit provided in an image recording apparatus of a third embodiment.

5 is a diagram showing the bit operation circuit of FIG. 4;

FIG. 6 is a diagram showing the vertical raster selection circuit of FIG. 4;

FIG. 7 is a diagram showing the data selection circuit of FIG. 4;

FIG. 8 is a diagram showing the data delay circuit of FIG. 4;

Claims (9)

[Claims] 1. A recording head in which a plurality of ink ejection nozzles are arranged in a line, a nozzle driving unit for ejecting ink from the nozzles according to image data, and a recording medium at a predetermined speed with respect to the nozzle driving unit. In an image recording apparatus having a conveyance unit that conveys the ink at a nozzle and a control unit that controls the operation timing of each unit, an ink ejection timing for delaying the ink ejection timing for each nozzle so as to cancel the positional deviation of the nozzle. An image recording apparatus comprising a delay unit. 2. The image recording apparatus according to claim 1, further comprising a data selection unit capable of arbitrarily selecting a plurality of image data for each nozzle. 3. The apparatus further comprises arithmetic means for performing a logical operation between adjacent raster lines, and data selection means for selecting either the arithmetic result by the arithmetic means or the image data before the arithmetic operation. The image recording apparatus according to item 1. 4. The image recording apparatus according to claim 1, wherein the recording head is an inkjet recording head that ejects ink to perform recording. 5. The recording head is a recording head for ejecting ink by utilizing thermal energy, and is provided with a thermal energy converter for generating thermal energy applied to the ink. The image recording apparatus according to item 1. 6. A recording head in which a plurality of ink ejection nozzles are arranged in a line, a nozzle drive means for ejecting ink from the nozzles according to image data, and a recording medium at a predetermined speed with respect to the nozzle drive means. In an image recording apparatus having a transporting means for transporting with each other and a control means for controlling an operation timing of each of the means, an ink ejection timing for each nozzle is delayed so as to cancel the positional deviation of the nozzle. Image recording method. 7. The image recording method according to claim 6, wherein a plurality of image data for each nozzle can be arbitrarily selected. 8. A method further comprising a calculation step of performing a logical calculation between adjacent raster lines, and a data selection step of selecting either a calculation result in the calculation step or image data before calculation. The image recording method according to item 6. 9. A recording head in which a plurality of ink ejection nozzles are arranged in a line, a nozzle drive means for ejecting ink from the nozzles according to image data, and a recording medium at a predetermined speed with respect to the nozzle drive means. A computer-readable storage medium storing a program code of an image recording method in an image recording apparatus having a conveying means for conveying by means of and a control means for controlling the operation timing of each means, and offsetting the positional deviation of the nozzle. As described above, the storage medium is provided with a code for the step of delaying the ink ejection timing for each nozzle.