JPH03199052A - Copying apparatus - Google Patents

Abstract

PURPOSE:To correct the unevenness of printing density by equipping an image- reading means for reading the printing result on a recording material and a correcting means for conducting the correcting of printing density on the basis of the output of the image-reading means. CONSTITUTION:When the unevenness of density of a printing result occurs or a print head is exchanged, a specified pattern is first generated by a printing pattern generator and converted into a binary by a binary converter 208 to form printing bit data. On the basis of the data, print heads 109(C), 109(M), 109(Y) and 109(K) perform printing actions by a print controller 117. Then, when a printing paper 116 with printed letters is transferred onto a manuscript stand glass, the printing result is read by an image sensor 108 and corrected data from the image sensor are stored by a corrected data sampling part 210. On the basis of the corrected data, an operation work is conducted by an arithmetic controller 211 and the corrected data for every bit of each head are prepared and transferred to a printing density correction part 209. In this manner, the density correction part controls gamma characteristics of image data for every bit to adjust a printing density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a copying apparatus using an inkjet method.

[Conventional technology]

Conventionally, printers and copying devices using inkjet have been equipped with a system for detecting the print spot position and print diameter in order to prevent uneven density of printed matter, as described in Japanese Patent Publication No. 57-501568. It is equipped with a printing means and an optical reading means, and based on the results, printing timing, printing intensity, etc. are corrected to obtain an appropriate image.

Furthermore, when correcting the print density, when using a copying machine with multiple nozzles, the number of correction data increases as the number of nozzles increases, so it is necessary to create correction data for each bit of the head in advance. . Therefore, in order to create correction data, a predetermined amount of printing is performed at a certain uniform density, the print result is read by another reading device, correction data is created for each bit based on this sampling data, and the ROM etc. , and the density is corrected for each bit installed in the main device.

Here, the cause of print density unevenness will be explained with reference to FIG. FIG. 5 shows an example of copying in which a plurality of nozzles are arranged at uniform intervals, printing is performed at the same timing, and the printing paper moves at a constant speed.

In FIG. 5, (1) is a normal case, where printing is evenly printed on the left and right sides, and no density unevenness occurs.

In FIG. 5(2), the printing is shifted to the left by α in the nozzle arrangement direction, so that the left side is thinner and the right side is thinner, resulting in uneven density.

(3) in Figure 5 is a case where the center nozzle is shifted by β in the printing paper movement direction, and since the overlapping printing and non-printing areas are different from (1) above, density unevenness occurs in the center. .

The above example is a case in which all print diameters are the same, and even if the print diameters are different, density unevenness will similarly occur.

[Problem to be solved by the invention]

However, in the above conventional example, it is necessary to have a dedicated light source and reading sensor to detect the print dot diameter and printing misalignment, and in order to perform highly accurate detection, it is necessary to configure an expensive reading system. However, there were drawbacks such as high cost.

Furthermore, in the case of a copying machine with multiple nozzles, it is necessary to create correction data for each head in ROM, and
M creation work is required, which is not only time-consuming, but also requires a one-to-one correspondence between the head and the ROM, so for distribution purposes, it is necessary to package the head together with the ROM.
The disadvantage is that the packaging method becomes difficult.

Furthermore, if the number of printing nozzles is greater than the number required for position control when installing the print head, it is necessary to create more of the above correction data than necessary, and for pattern printing to sample the correction data. A special printing device other than a copying device is required.

SUMMARY OF THE INVENTION In view of the above-mentioned points, an object of the present invention is to provide a copying apparatus with print correction that reads uneven print and performs density correction.

[Means for Solving the Problems 1] The present invention provides a copying apparatus using an inkjet system, which includes an image reading means for reading a print result on a recording material, and correction of print density based on the output of the image reading means. The apparatus is equipped with a correction means for performing the following.

[Function J] According to the present invention, for example, print density unevenness is automatically read using a high-resolution reading system of a copying machine without installing a new reading section, and the print density unevenness is corrected by image processing or a print correction section. By performing the correction, low-cost print density correction is realized.

Furthermore, since the print density correction data can be sampled using only this device, there is no need for a data ROM for print density correction, which is conventionally required in the case of multiple nozzles.

〔Example] Examples of the present invention will be described in detail below.

Aishi Shiyu FIG. 1 is a drawing showing an entire embodiment of the present invention.

In the figure, reference numeral 101 denotes a document table glass on which a copy original and a copy result for print correction are placed; 102 and 103 a light source and a reflective shade for illuminating the original on the document table glass; 104;
．． 105 and 106 are reflecting mirrors for guiding the light from the original to the reading section; 107 is a lens for condensing the light from the original guided by the reflecting mirrors 104, 105, and 106; and 10g is an image sensor that photoelectrically converts the light from the original. be. 109 (C
), 109 (M), 109 (Y), 1
09 (K) are print heads, C, M, Y
, represents the color.

110 is a belt on which printing paper is placed; 111 is a distinguishing claw that distinguishes between normal paper ejection and paper feeding for returning the print result during correction to the platen glass; 112 is a paper ejection roller; 113.1
14. 115 is a conveyance roller for feeding the print result at the time of correction to the platen glass; 116 is a sheet of paper to be printed; 1
17 is a print control unit that controls the print head 109;

FIG. 2 shows the electrical configuration of the image processing section 117.

This device is operated by the operation unit 212 shown in FIG.
Normally, a copy operation is performed. In this case, the print paper is printed by the print head 109 while moving from right to left on the print belt 110 at a constant speed, and the print result is ejected by the paper ejection roller 112. Note that the distinguishing water 111 at this time is upward.

Therefore, when density unevenness occurs or changes in the print result, or when the print head is replaced, by selecting the correction mode using the operation unit 312, the distinguishing water 111 moves downward, and the following steps are performed. Sample the print correction data using .

First, a specified pattern is generated by a print pattern generation section, and is binarized by a binarization section 208 to create print bit data.

Based on this data, the print control unit 117 controls the print heads 109 (C), 109 (M),
109 (Y) and 109 (K) perform printing operations. However, in order to prevent color mixing in the print results, the print timing of the print heads is controlled in accordance with the movement of the paper.

Next, the printing paper 116 on which the pattern has been printed is carried upward by the distinguishing water 111, and the correction paper feeding rollers 113, 1
14 and 115 onto the document table glass.

Furthermore, the image sensor 108 detects that the printing paper 116 is placed on the document table glass, the image sensor 108 reads the printing result, and this correction data is stored in the correction data sampling section 210.

Then, based on this correction data, the calculation control section 221 performs calculation work to create correction data for each bit of each head, and transfers this correction data to the print density correction section 209.

This operation completes the print density correction operation, and based on this correction data, the print head density correction section controls the γ characteristic of the image data for each bit to control the print density.

It goes without saying that by transferring this correction data to a RAM that can be backed up, it can be saved regardless of whether the power source is 0N10FF.

The above explanation is shown in a flowchart as shown in FIG.

Another embodiment is shown in FIG. 4. In contrast to the first embodiment, the present embodiment is a system in which there is no need to convey the print paper 116 on which the print correction pattern is printed onto the platen glass in order to perform print correction, and the reflecting mirror 106 is moved by 90 degrees. Reflection mirrors 402 and 403 are added to enable the image sensor 108 to read the pattern printed on the printing paper 116 placed on the conveyor belt. Reflection mirror 4
01 is provided to guide light from light sources 102 and 103. As for illuminating the print paper 116, by providing another light source at the position 404, it can also be used for drying the print.

It should be noted that the present invention provides excellent effects particularly in bubble jet recording heads and recording apparatuses among ink jet recording systems.

This is because such a system can achieve higher recording density and higher definition.

As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796. 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, it is necessary to arrange the liquid (ink) in accordance with the sheet and liquid path that hold it. The electrothermal converter that is
Generating thermal energy in the electrothermal transducer and producing film boiling on the thermally active surface of the recording head by applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise above nucleate boiling. As a result, bubbles in the liquid (ink) can be formed in a one-to-one correspondence with this drive signal, which is effective. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one droplet. If this drive signal is in the form of a pulse, bubble growth and contraction will occur immediately and appropriately.
Particularly responsive liquid (ink) ejection can be achieved,
More preferred. This pulse-shaped drive signal is described in U.S. Pat. Nos. 4,463,359 and 4,345,262.
Those described in the specification are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

The configuration of the recording head includes, in addition to the combination configuration of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, a heat acting section. 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 wafer is placed in a bending region. In addition, Japanese Patent Application Laid-Open No. 1989-5 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters.
No. 9-123670 and Japanese Patent Application Laid-Open No. 59/1989 which discloses a configuration in which a discharge portion is made to correspond to an opening that absorbs pressure waves of thermal energy.
The effects of the present invention are also effective even if the structure is based on the publication No.-138461. In other words, regardless of the form of the recording head, recording can be performed reliably and efficiently.

Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by a recording apparatus.

Such a recording head may have either a configuration in which the length is satisfied by a combination of a plurality of recording heads, or a configuration as a single recording head formed integrally. In addition, even the serial type shown above can be installed on the main body of the device, allowing for electrical connection to the main body of the device and supply of ink from the main body of the device.Replaceable chip type recording heads. Alternatively, the present invention is also effective when using a cartridge type recording head that is integrally provided with the recording head itself.

In addition, in addition to being used as an image output terminal for information processing equipment such as a computer, the inkjet recording apparatus of the present invention may also take the form of a copying machine combined with a league, etc., or a facsimile machine having a transmission/reception function. It may be something.

Ru.

Therefore, a special device (a printing device compatible with multiple nozzles) for creating the above-mentioned correction data ROM becomes unnecessary.

〔Effect of the invention〕

As explained above, according to the present invention, in a copying machine with print correction that corrects print unevenness and reading density in an inkjet type copying machine, for example, by using the document reading section of the copying machine, the printing There is no need to provide a special advanced reading device to detect the dot diameter and deviation of the dots, and costs can be reduced.

Furthermore, since there is no longer a need for a ROM that stores correction data for each bit for print density correction when multiple nozzles are used, not only is the cost reduced, but it has been previously impossible to store this correction data for each head. Since the previously created motion is no longer necessary, the time required to create the head is shortened, mass productivity is improved, and since only the head needs to be packed, handling becomes easier.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the entire embodiment of the present invention, Fig. 2 is a block diagram showing the detailed configuration of the printing control section, Fig. 3 is a flowchart showing an example of the control procedure, and Fig. 4 is another example of the implementation. A diagram showing an example, FIG. 5, is a diagram illustrating uneven print density. ...Document table glass, ...Light source, ~106...Reflection mirror...Lens, ...Image sensor, ...Belt, ...Sheet discharge roller, ...Print control unit. Figure 4 (Miqmi

Claims (1)

[Scope of Claims] 1) In a copying apparatus using an inkjet method, an image reading means for reading a print result on a recording material, and a correction means for correcting print density based on the output of the image reading means. A copying device characterized by comprising: 2) The copying apparatus according to claim 1, wherein ink is ejected from a plurality of nozzles when printing on the recording material. 3) The copying apparatus according to claim 1, wherein a reading system of a main body of the copying apparatus is used as the image reading means.