JPH02235752A - Ink jet recording apparatus and method - Google Patents

Abstract

PURPOSE:To obtain a good image having no white or black stripes even when recording is performed in any ink amount by confirming the amount of ink emitted at the time of recording due to a recording head in a predetermined direction and controlling the relative moving quantity of the recording head and a material to be recorded corresponding to the confirmation result. CONSTITUTION:At each time when one main scanning is started, a control part 30 clears an integrator 23 to again operate the same. When the recording of one line is completed, a carriage 6 is subjected to main scanning in a reverse direction and the integral value of image data recorded on one line is outputted. This integral value becomes an amount showing the amount of the ink recorded during one main scanning. The integral value of an image signal and the driving quantity of a pulse motor 3 at the time of proper sub-scanning corresponding to said value are stored in an ROM 25 in corresponding relation and the ROM 25 is used to obtain the optimum auxiliary scanning feed quantity (the number of the driving pulses of the motor in said ink amount) and the pulse motor 3 is driven to perform sub-scanning.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an inkjet recording device and an inkjet recording method, and is particularly suitable for application to a serial scan type inkjet recording device.

[Prior Art] Conventionally, as an image recording device, an inkjet recording device that performs recording by ejecting ink onto a recording material is known. Inkjet recording devices are non-impact recording devices with features such as low noise and the ability to easily record color images by using multicolored inks, and have become rapidly popular in recent years. be.

FIG. 9 shows an example of a schematic configuration of a serial scan type inkjet recording apparatus.

In FIG. 9, 1 is a recording material in the form of roll paper;
The paper is supported by a feeding roller 2 via conveying rollers 4 and 5, and is sent in the direction f in the figure by driving a sub-scanning pulse motor 3 coupled to the feeding roller 2. A guide rail 10 is arranged in a predetermined direction with respect to the recording surface of the recording material 1, and an inkjet recording head 7 mounted on a carriage 6 is moved along the guide rail 10 by a main scanning motor 9 via a timing belt 8. main scan from left to right.

This recording head 7 is connected via a tube 11 to an ink tank 12 which serves as an ink supply source. Further, this recording head has a plurality of ink ejection ports arranged in the sub-scanning direction, and has an ejection energy generating element such as an electrothermal transducer corresponding to each ejection port.

The recording material 1 is intermittently sub-scanned in the f direction by an amount corresponding to the recording width of the inkjet head 7 during main scanning, that is, the array range of the ejection ports. The recording head scans in the P direction while the printer is in use, and in the process, ink is ejected in accordance with the image signal input via the flat cable l3.

In such an inkjet recording apparatus, the amount of sub-scanning of the recording material has a significant effect on image quality. In other words, when the sub-scanning amount is smaller than the recording width of the recording head, an unrecorded area remains between the strip-shaped parts recorded in each main scan, and white stripes occur in that area. This is because when the size is small, the recorded portions partially overlap, resulting in black stripes. For this reason, it is simply necessary that the sub-scanning amount exactly match the recording width.

[Problem 8 to be solved by the invention] However, some commonly used recording materials have the property of expanding when they absorb ink, and the required sub-scanning feed amount changes depending on the amount of ink to be recorded. As a result, a problem arises in that white stripes or black stripes occur at the boundaries between the strip-shaped recorded portions.

This problem will be explained using FIG. 10.

When the amount of recorded ink is small, such as when recording bright halftones, the elongation of the recording material is not so great, so the width of the recorded image is approximately equal to the recording width d of the head 7. Therefore, if the recording head is main-scanned in the A direction to perform recording, and then the recording material is sub-scanned in the B direction by d, the recording for each main scan will be completed as shown in Figure 1θ (^). Seams are not a problem.

However, when recording an image in a high-density area, the amount of ink recorded becomes large and the recording material stretches due to ink absorption, so the width of the recorded image becomes d+Δd. At this time, if the sub-scanning amount of the recording material is d, the images will overlap with a width of Δd, and a black stripe will occur in this portion, as shown in FIG. 10 (CB). On the other hand, if the sub-scanning amount is set to d+Δd, there will be no problem when recording an image in a high density area, but white streaks will occur in a bright highlight area.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet recording apparatus and method that can produce images of good quality without white streaks, black streaks, etc., regardless of the amount of ink recorded.

[Means for Solving the Problems] To this end, in a first embodiment of the present invention, inkjet recording performs image recording by relatively moving a recording head that performs recording by ejecting ink and a recording material. The apparatus is characterized in that it includes a recognition means for recognizing the amount of ink ejected during printing in a predetermined direction by the print head, and a control means for controlling the relative movement amount according to the recognition result by the recognition means.

Further, in the inkjet recording method according to the second aspect of the present invention, when recording an image by relatively moving the recording head that performs recording by ejecting ink and the recording material, The present invention is characterized in that when the head prints in a predetermined direction, the amount of ink ejected from the print head is recognized, and the relative movement amount is controlled in accordance with the recognition result to perform image printing.

[Function] In the present invention, for example, in a serial scan type inkjet recording device, one recording in a predetermined direction (main scan)
By comprising a means for detecting the amount of ink recorded in the recording material, and a means for changing the relative movement amount (sub-scanning amount) between the printing end and the recording material according to the detected amount of ink. , No matter what amount of ink is used for recording, a good image without white streaks or black streaks can always be obtained.

[Example] Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a sub-scanning control system of an inkjet recording apparatus according to an embodiment of the present invention, which is specifically applicable to the configuration shown in FIG. 9.

Here, 21 is an image signal supplied from the control section 30. The inkjet recording head 7 includes a plurality of ink ejection ports arranged in the sub-scanning direction and an ejection energy generating element disposed corresponding to each ejection port. It has an electrothermal conversion element. 23 is an integrator that integrates image signals for each main scan, and 24 is an output signal that indicates the integrated value.

Reference numeral 25 denotes a ROM that stores the integrated value of the image signal and the appropriate drive amount of the motor 3 during sub-scanning in correspondence with the integrated value. 26 is a signal indicating the drive amount, and the drive circuit 2
7 drives the pulse motor 3 accordingly. for example,
When the length of the recording material being used in the sub-scanning direction changes as shown in FIG. 2 depending on the amount of recording ink, the ROM 25 stores a table as shown in FIG. It is converted into a signal indicating the number of drive pulses of the motor 3 at the time.

Here, Fig. 2 shows the elongation of the recording material for one main scanning recording when d = 16 mm, for example.
It shows that it extends by ~60 μm. Also, Figure 3 shows 6
This shows the case where sub-scanning of 5μ peaks is performed with one pulse when the length is extended by 0 μm. Normally, sub-scanning is performed with 3200 pulses, but in the case of solid printing, sub-scanning is performed with 3212 pulses.

The drive circuit 27 generates a pulse motor drive signal 28 having the same number of pulses as the sub-scanning pulse number signal 26, thereby driving the sub-scanning pulse motor 3.

FIG. 4 shows the operation procedure during recording processing with the above configuration, which can be performed under the control of the control section 30, for example.

First, at each start of one main scan, the control unit 30 controls the integrator 2.
3 is cleared and it is operated again (step St).

Subsequently, the carriage 6 is moved to a predetermined home position in step S2, the main scanning motor 9 is driven in step S3 to start main scanning of the carriage 6, and the main scanning of the carriage 6 is started in step S4.
Start recording. When the recording of one line is completed in step S5, the carriage 6 is caused to main scan in the reverse direction in step S6, and the integrated value of the image data recorded in one line is outputted in step S7. This integrated value represents the amount of ink printed during one main scan. Next, in step S8, the ROM 25 is used to obtain the maximum sub-scanning feed amount (motor drive pulse number) for the ink amount, and in step S9, the pulse motor 3 is driven accordingly to perform sub-scanning. I do.

Next, in step 510, it is determined whether recording for one sheet has been completed, and if it has not been completed, the process returns to step S1 and the above-described sequence is repeated. On the other hand, if it is finished,
The carriage 6 is returned to the home position in step Sll, the paper is ejected in step 512, and the series of operations ends in step 513.

According to the tree example, even if the required sub-scanning amount changes due to an increase in the amount of recording ink and the elongation of the recording material, the pulse motor 3 for sub-scanning will perform the sub-scanning by the number of pulses corresponding to the amount of ink. Therefore, optimal sub-scanning is always performed, resulting in a good image without white or black lines.

Next, a second embodiment of the present invention will be described.

Although the embodiment described above is applied to the configuration shown in FIG. 9 that performs single-color recording, this embodiment can also be applied to an apparatus that performs color recording.

FIG. 5 shows the sub-scanning control system of this embodiment, in which the same components as in FIG. 1 are denoted by the same reference numerals.

In this embodiment, the inkjet recording head 7a corresponds to four colors, for example, cyan, magenta, yellow, and black.
~7d, respectively, in cyan, magenta, and yellow. Ink is ejected according to image signals 21a to 21d of each color of black to form a full-color image.

Then, the four color signals 2]a to 21d are manually input to an adder 31, and the sum of the four color signals is output as an addition signal 32. The integrator 23 outputs an integrated signal 24 for each main scan. Therefore, this integrated signal 24 represents the total amount of ink recorded by the heads for four colors during one scan. Next, the ROM 25, the drive circuit 27, and the pulse motor 29 perform sub-scanning with an optimal sub-scanning amount according to the total amount of ink, as in the first embodiment, to obtain a good image without white or black lines. Full color images can be obtained.

Next, a third embodiment of the present invention will be described.

Some inkjet recording devices contain coated paper. plain paper,
There are devices that can record images on various recording materials, such as OHP films. However, since the relationship between the amount of recording ink and the amount of elongation of the recording material differs depending on the type of recording material, the conversion table from the integrated signal to the number of sub-scanning pulses is 1 fffi type, as shown in FIG. In some cases, it may not be possible to handle multiple recording materials.

This embodiment solves this problem by switching the conversion table depending on the type of recording material.

FIG. 6 shows a third embodiment of the present invention, in which the same components as in FIG. 1 or 5 are given the same reference numerals.

In FIG. 6, reference numeral 33 denotes a recording material selection means, which generates a recording material selection signal 3i indicating the type of recording material to be used, and stores a conversion table corresponding to the type of recording material. Input to a certain ROM 25. This recording material selection means is
The operator may identify the recording material used and specify the type of recording material from an operation section (not shown), and also detect the thickness, reflectance, whiteness, shape, etc. of the recording material. It may also be possible to automatically determine the type.

In the case of an inkjet recording apparatus that uses three types of recording materials with different relationships between the amount of recording ink and the length of the recording material in the sub-scanning direction as shown in A, B, and C in FIG. 7, the ROM 25
stores three types of conversion tables such as E, F, and G in FIG. When the selection signal 34 corresponding to the recording material C is manually entered into the ROM 25, the conversion tables E, F, and G are used, respectively.

With this configuration, even if the type of recording material changes, a good image without white streaks or black streaks can always be obtained.

In each of the above embodiments, the inkjet recording head performed only the main scan, and the sub-scan was performed by conveying the recording material, but the present invention is not limited to this, and the recording material is fixed. The head may perform main scanning and sub-scanning.

[Effects of the Invention] As explained above, according to the present invention, there is provided a means for detecting the amount of ink recorded during one main scan, and a means for changing the amount of sub-scanning according to the detection result. As a result, it is now possible to obtain good images free of white streaks and black streaks no matter what amount of ink is used for recording.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the sub-scanning control system of the inkjet recording apparatus of the present invention, FIG. 2 is an explanatory diagram showing the relationship between the amount of recording ink and the elongation of the recording material, and FIG. 3 is an image signal FIG. 4 is a flowchart showing an example of the operating procedure of this embodiment. FIGS. 5 and 6 show two other embodiments of the present invention. The block diagram, Figures 7 and 8 respectively show the relationship between the amount of recording ink and the elongation of the recording material depending on the type of recording material, and the relationship between the integrated value of the image signal and the sub-scanning amount. FIG. 9 is a perspective view showing a configuration example of a serial scan type inkjet recording apparatus, and FIGS. 10 (A) and (B) are explanatory views for explaining the mechanism of streak generation due to sub-scanning. DESCRIPTION OF SYMBOLS 1... Recording material, 3... Sub-scanning pulse motor, 7.7a-7d... Inkjet recording head, 23
...Integrator, 25...ROM, 27...Drive circuit, 30...Control unit, 3l...Adder, 33...Recording material selection means. Figure 2 Figure 3 = (Summa 鴛t蓓; q１一冫鵠(ノ一N7χ→ト二(A)) Figure 10

Claims (1)

[Scope of Claims] 1) In an inkjet recording apparatus that records an image by relatively moving a recording head that performs recording by discharging ink and a recording material, the recording head discharges ink when recording in a predetermined direction by the recording head. An inkjet recording apparatus comprising: a recognition means for recognizing an amount of ink that is moved; and a control means for controlling the relative movement amount according to a recognition result by the recognition means. 2) The inkjet recording apparatus according to claim 1, further comprising means for changing the relative movement amount depending on the type of recording material. 3) The inkjet recording apparatus according to claim 1, wherein the recognition means includes an integrator that integrates image signals for each main scan. 4) When performing image recording by relatively moving a recording head that performs recording by discharging ink and a recording material, the amount of ink discharged from the recording head when recording in a predetermined direction by the recording head. An inkjet recording method, characterized in that the image is recorded by recognizing the relative movement amount according to the recognition result.