JP2007136951A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change calibration conditions according to a selected print mode when performing calibration in an image forming apparatus having a plurality of print modes.
SOLUTION: In the normal printing mode, relatively standard calibration is performed, in the quality priority mode, more detailed calibration can be performed, and in the draft mode, labor is saved so that color matching can be easily performed. Control is performed such that the optimum means is automatically selected according to the print mode selected to perform calibration. An image forming apparatus.
[Selection] Figure 1

Description

  The present invention is an image forming apparatus having image forming means for forming an image mainly by discharging ink, and in particular, a recording head for recording by discharging ink to a recording medium at the time of image formation moves the recording medium. This is an image forming method related to a so-called multi-scan type image forming method in which image formation is performed while scanning substantially perpendicularly to a direction. These relate to, for example, an image forming apparatus having functions such as a printer, a copying machine, a facsimile, or the like, or an image forming apparatus used as an output device of a multifunction peripheral including a computer or a word processor or a workstation.

  Typical image forming methods of recording means (or recording units) that have been widely used in image forming apparatuses conventionally include ink jet methods, wire dot methods, thermal methods, sublimation / thermal transfer methods, electrophotographic methods, and silver halide photography. There are methods. Among them, the ink jet method has an advantage that high image quality can be obtained for various recording media with relatively simple means and configuration, and has been widely used.

  This ink jet type image forming method is roughly classified into a serial type and a full line type. In a serial type image forming apparatus in which the main scanning direction is a direction crossing the conveyance direction of the recording medium, the recording medium is set at a predetermined recording position and then moved on the carriage that moves along the recording medium (main scanning). An image (including characters and symbols) is formed by the mounted recording means (recording head), a predetermined amount of paper is fed (sub-scanning) after the recording for one line is completed, and then the image of the next line By repeating the operation of forming (main scanning), an image is formed in a desired range of the recording medium. This serial type includes a one-way printing method in which printing is performed only from the image writing position (HP) side and a bidirectional printing method in which printing is performed while scanning from the opposite side after scanning on the HP side. Furthermore, in the serial type, the multi-scanning image forming method for forming an image at a plurality of times (overlapping multiple times), instead of forming an image at a single main scan as described above, as described above. This is called a method.

  On the other hand, in a full-line type image forming method in which the recording medium is recorded only by sub-scanning in the transport direction, the recording medium is set at a predetermined recording position, and recording for one line is continuously performed all at once. A predetermined amount of paper feed (pitch feed) is performed. Then, an image is formed on the entire recording medium.

  Most of the image forming methods that have been widely used in recent years are multi-scan image forming methods among the serial types. In an image forming apparatus using such an image forming method, when the quality is poor, image formation is performed by one or two main scans. When high quality output is performed, the image forming apparatus performs 10 times or more. It is not uncommon to superimpose. Such differences include not only the type of paper used for output, but also the image forming apparatus having various types of print modes when the person who wants to output selects the quality, or a combination of both.

  Therefore, in the present invention, an image forming apparatus in which at least two types of print modes can be selected as described above is most suitable and widely used. Therefore, the present system will be described as a representative in detail below. .

  However, of course, even in a full-multi type recording apparatus, the sub-scanning (conveyance) speed of the recording medium is changed depending on the recording medium, and in the case of the electrophotographic system, similarly, the output speed is reduced for paper such as thick art paper. In such a case, the same effect as in the above case can be obtained.

  First, the present invention is characterized in a method of selecting an image adjusting unit and a method of changing the operation of the adjusting unit, and a device configuration to which the present application is applied basically does not require a special configuration. Although it will be described later with reference to an embodiment, typical adjustment means will be described before that.

  A typical configuration of the adjusting means includes a case where an ink droplet actually ejected is measured and a case where an output result is measured. The latter is most easily used. Therefore, the latter case will be described as an example. In this method, a means for printing a patch (or image) for measuring density or ink density on a recording medium recorded by an ink jet recording system or on a recording medium that substitutes the recording medium and reading the patch is read. It is common to have density correction means that can perform density correction according to the reading signal from the means and reading means. That is, not only the image forming unit but also a reading unit is required. This reading means may also be a conventionally proposed one. For example, it is common that there is a reading means in the apparatus as in Patent Document 1, for example. Further, as proposed in Patent Document 2, a recording medium may be recorded and read on a belt that carries and conveys a recording medium. Such an example will be described with reference to the drawings. First, FIG. 7 shows an image forming apparatus in the form of a copying machine (and a multi-function) using a full multi-head described in Patent Document 3. In the case of an apparatus having a scanner as described above, the output recording medium as described above can be read by a dedicated scanner. In such a case, if density correction is necessary, if the main unit has a liquid crystal display, a message such as `` Nodose Shitaku Daisai '' will be displayed there, a warning system with an error lamp, buzzer, etc. It was effective to prompt density correction by displaying an operation warning via a printer driver or a dedicated utility. The case where a reading sensor is provided inside the main body (inline) is no exception. An example is shown in FIG. This figure is also a full-line type recording apparatus (see Patent Document 2), but in the case of this example, a reading sensor is provided on the conveyor belt, and reading is performed in-line after recording. Further, in this case, since the patch is printed on the conveying belt instead of printing on the recording medium, there is an advantage that the type of the recording medium is not bothered and the paper is not wasted. .

  FIG. 9 shows an example of serial scanning. This example is an example described in Patent Document 1 and has an exclusive recording medium outside the recording paper for image output.

  As described above, various types of conventional examples have been proposed, but the present invention is not related to these configurations, but only to a control method.

Furthermore, a scanner represented by a general-purpose flatbed system that can be connected to a widely used personal computer or the like, or a reading unit of a copying machine may be used. It is not an exception.
Japanese Patent Laid-Open No. 5-124221 (FIG. 16) JP-A-6-95474 (FIG. 21, Example) Japanese Patent Laid-Open No. 4-18357 (FIG. 3)

  However, in the example such as the above-mentioned reference, the time for outputting the pattern may differ depending on the paper type as the labor and control time, even if it is desired to match colors easily or in detail. However, since there is no means for deliberately optimizing the adjustment accuracy after scanning, the time required for adjustment, ink consumption, paper usage, etc. may be wasted, and it is required to make detailed adjustments. There was a problem that the accuracy to be obtained could not be obtained.

(the purpose)
As described above, according to the present invention, when the adjustment unit is executed in the image forming apparatus having a plurality of print modes, the user can select the print quality, the paper type, etc. by changing the operation condition of the adjustment unit according to the selected print mode. The purpose is to provide an image forming method that optimizes the time and paper consumption, as well as the output result, by selecting the optimum operating condition of the adjustment means according to the printing mode being used and the environment It is said.

  As described above, the data conversion means for converting to output data based on the image data, the image forming means for forming an image based on the output data, and the output result by the image forming means is not a desired output or desired output An adjustment unit that adjusts the data conversion unit when it is expected to be different from the image, and further selects or predicts a desired output quality to determine a print mode and performs image formation by the image formation unit The forming apparatus includes an adjustment method selection unit that changes the adjustment method of the adjustment unit in accordance with the quality of the determined printing mode, thereby optimizing the effort and effect applied to the adjustment unit.

  Further, the second aspect of the invention is that when the adjustment method selection means is at least low quality, either the time required for the adjustment means, the number of operations, or the consumables to be consumed is reduced or the quality is high. By using either or both means for selecting the adjustment method so that the adjustment accuracy is improved, the time and paper consumption are optimized according to the quality to be output.

  According to a third aspect of the present invention, there is provided a data conversion unit that converts output data based on image data, an image forming unit that forms an image based on the output data, and an output result by the image forming unit that is not a desired output or desired The adjustment means for adjusting the data conversion means and the adjustment amount of the adjustment means are determined in accordance with the output of the adjustment pattern, the reading of the adjustment pattern, and the read value thereof. In the image forming apparatus as the adjusting unit, when the adjusting unit is executed, an output quality is selected or predicted to determine a print mode of the adjustment pattern, and when the image forming unit performs image formation, the determined print mode By changing the time interval from the output of the adjustment pattern of the adjustment means to the reading according to the quality or the paper type Spend the accuracy of the adjustment means required paper type is obtained so as to optimize the time and.

  In the fourth invention, the adjustment method is changed for each color to further optimize for each color.

  As described above, the invention according to the present proposal is optimal for an image forming apparatus having an adjustment unit necessary for maintaining the quality of an output image according to the quality that a user using the image forming apparatus is to output. By providing an adjustment method selection means for adjustment methods, it is necessary to adjust more carefully than necessary using more time and consumables, or adjust more easily than necessary, and the desired adjustment accuracy may not be obtained. This has the effect of suppressing the operation.

  Therefore, as described above, the present invention suppresses the waste of consumable materials and user's labor and time, and solves the insufficient function, and can suitably stabilize the configuration of each image forming apparatus.

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

(Image forming device)
(Description of configuration)
FIG. 1 illustrates the most typical flow of this embodiment. FIG. 2 shows changes in patch density over time when an arbitrary patch is read by the image forming apparatus used in the embodiment. FIG. 3 is a diagram for explaining a time difference from when a patch is output to when the patch is read. FIG. 4 shows a printing operation of a typical printer when carrying out these operations.

  In the embodiments of the present invention to be described below, the image forming apparatus to be used is a serial type ink jet printer that has been widely implemented and proposed as described above. It is assumed that the image forming apparatus is a bidirectional printing type that forms an image by superimposing by direction scanning. In addition, the number of times of superimposition at this time is referred to as the number of passes. (For example, when image formation is performed by overlapping an arbitrary image four times, this is referred to as four passes.) In this image forming apparatus, the moving direction of the recording medium is generally set as the sub-scanning direction. On the other hand, the substantially vertical direction is defined as the main scanning direction. At this time, the recording head includes a nozzle row in which a plurality of ink ejection ports are arranged in the sub-scanning direction. In general, one nozzle row corresponds to one color of ink, and there are often a plurality of rows in the main scanning direction. The present invention is not particularly limited to the number and arrangement order of the nozzle rows. For the sake of simplification of description, 4 (black (BK), cyan (C), magenta (M), yellow (Y)) is used. A case where colors are used will be described.

  In FIG. 4, the recording head 1 can scan in a substantially vertical direction (arrows X and X ′ in the figure) with respect to the moving direction (Y direction in the figure) of the recording medium (so-called recording paper) 50 on which the recording head 1 is simply displayed. Indicates the state. The recording head 1 is provided with nozzle rows for each color as shown in the order of black 1K, cyan 1C, magenta 1M, and yellow 1Y.

  First, a normal printing operation will be described. When an image signal is first input and recording is started, the recording medium 50 is conveyed to the state (1) in the figure. Then, the recording head 1 scans in the X direction in the drawing, and as shown in the drawing, the first line is formed by the lower end of the nozzle row (in the figure, since there are 8 passes, any 1/8 nozzle from the bottom). Thereafter, the recording medium 50 is conveyed to the state (2). Then, scanning is performed in the direction of the arrow X ′ in the figure, and the first and second lines are imaged by an arbitrary 2/8 nozzle from the lower end. (Of these, the second line refers to a line that is overlapped twice at the same location.) In this way, the repeated scanning is continued in the reciprocating direction, and the seventh line corresponds to the nozzle row. Then, after an image is formed by an arbitrary nozzle of 7/8 from the lower end and the recording medium is conveyed to the next state (8), image formation is performed by the entire nozzle row for the first time. Thereafter, as shown in (9) in the figure, an image is formed while forming only lines from 1 line to 8 lines.

  .., 7 and odd scans, the forward direction (X direction in the figure), and 2, 4,... 8 and even scans, the reverse direction (X ′ in the figure) is printed.

  Next, adjustment means in the recording apparatus will be described. The adjusting means used in this embodiment forms an image of an arbitrary patch on a recording sheet prepared in advance so that an image can be formed on the image forming apparatus. The patch or recorded recording medium is moved to a predetermined location. Read by the reading means in the machine at that place. If the patch is in an ideal state, a predetermined density should be obtained, but if a deviation is detected, a predetermined amount is corrected. Here, the correction is to change the parameters of the data conversion means so that if the density is low, the density is high, and if the density is low, the density is reduced.

  Here, in the above-described embodiment, it has been described that the patch or the recording medium on which the patch is formed is moved. However, the reading unit may be moved without moving the recording medium, or both may be moved. If the output result can be read and the parameters of the conversion means can be optimized based on the result, there is no problem in the present invention.

(Description of operation)
In this embodiment, first, a case where the present invention is applied to the image forming apparatus will be described.

  In FIG. 1, an image forming apparatus using four colors of ink for each of cyan (C), magenta (M)), yellow (Y), and black (K) will be described as an example. The normal printing operation and the operation at the time of adjusting means, and the flow for selecting the adjusting means are described, which will be described below.

  Image data used in a normal printing operation is input from (10) in the figure. In recent years, this image data (10) is often taken with a flatbed scanner, a digital camera, and the like, and since there are many multivalued signals expressed in RGB color space, the case of RGB multivalued data is described as a representative example. is doing. However, the present invention is not particularly limited to such a format of input image data. As another example, a multilevel signal in the CMYK color space, a signal binarized for each color space, a quantized / encoded signal, or the like may be used, and monochrome data may be used.

  The input image data (10) is color-separated into CMYK ink color data in a printer color reproduction color conversion table (abbreviated as TBL in the figure). Then, the image data corresponding to each ink color is converted into a binary signal corresponding to the pixel, and transmitted to the recording head as an ejection signal so as to determine whether ejection is possible for each pixel. On the other hand, the recording head receives the ejection signal while performing the scanning operation at this time, and forms an image ((11) in the figure).

  In the image forming apparatus that performs the normal output operation as described above, the adjustment unit will be described below.

  First, when (12) is input as a detection signal indicating that adjustment is necessary, first, the method of the adjustment means is determined.

  The detection signal that adjustment is necessary is counted from the number of ink ejection operations, the count value of the number of printed sheets, the operation elapsed time, the head temperature signal, the temperature / humidity signal where the image forming apparatus is placed, etc. The image forming apparatus may automatically detect and create the image, or the person using the image forming apparatus may select it artificially.

  The determination of the adjustment method may be the printing mode used when the printing mode used before and after the selection is known. The print mode referred to here is typically color, quality, paper, and the like. First, the color is the number of colors used in monochrome, color, and color (for example, in the embodiment of FIG. 1, the case where four colors C, M, Y, and K are used has been described, but red (R), blue ( B), green (G), gray (Gy), gold, silver, and the case where special colors such as fluorescent color are used, these are represented by. Next, the quality is what ink jet printers that have been released recently, such as fast and beautiful, select at the time of output. Generally, the thinning rate, the maximum amount of ink used, the number of multi-passes, etc. are different. Is. Further, the paper includes designated paper and other papers in addition to the material type in the recording medium, such as plain paper, glossy paper, coated paper, and the like.

  How to adjust the adjustment means for the printing mode described above will be described separately.

  When the method of the adjusting means is determined, an output pattern corresponding to the method is determined and printed. Thereafter, the pattern stored in advance in the main body is output by the image means. Thereafter, time counting is started from printing, and reading is started when a reading start time is reached from a predetermined adjustment method, and a reading signal is acquired. Whether or not to perform the adjustment again is determined based on the read signal value or the number of repetitions determined in advance when the adjustment means method is determined, and if it is repeated, printing and reading of an appropriate pattern are repeated. When there is no need to repeat, the adjustment means is terminated by correcting the correction amount or the numerical value of the color conversion TBL according to each read signal value.

  Here, the repetition is also used to read the same number of patches as a large paper or a small paper when it is desired to improve the adjustment accuracy in addition to determining whether the reading has been normally performed.

  Next, the color adjustment pattern and how it is read will be described with reference to FIG. FIG. 3A shows a color adjustment pattern used by the color adjustment means. A, B, C, and D are patches of C, M, Y, K, and 4 colors, respectively. FIG. 3B simply illustrates the time from when the adjustment pattern FIG. 3A is printed to when each patch is read (in the figure, the time between measurements after printing).

  For simplicity of explanation, if patches of each color are printed from the left in the figure in one pass, the patches are printed in the order of A, B, C, and D. If all of them are read by one sensor, they are similarly read in the order of A, B, C, and D. At this time, by reading in the same order as the order of printing, the time between measurements after printing was prevented from being shortened by an arbitrary color. Here, FIG. 3B shows that the time is controlled so that each color has the same measurement time after printing.

  However, the pigment inks used in this example have almost the same tendency until any color is stabilized, but this is the case. However, as in the case of the dye R ink shown in FIG. If the characteristics are different so as not to stabilize, it is necessary to optimize the time between measurements after printing for each color. For example, as shown in FIG. 3A, in order to print the color according to the color stabilization as soon as possible, the pattern A is printed, the reading starts from B, and finally A is read. Is preferred.

  Thus, it is also a feature of the present invention that the time between measurements after printing is optimized for each color, and further, the time between measurements after printing is optimized according to the application. It is said.

  FIG. 2 is a graph showing how the color difference (ΔE94) changes with time when patches are output with a variety of inks on a certain glossy paper.

  In general, pigment inks have better color stability after printing than dye inks. Also in the figure, in the case of dye red (R), it can be seen that ΔE94 changes by about 3 while the pigment ink satisfies ΔE ≦ 1.4 even for bad colors. Thus, it can be seen from the figure that even with a relatively preferred ink, the color does not stabilize unless it takes about 3 minutes.

  However, if the user always waits for reading for 3 minutes after patch printing at the time of color adjustment, the user is made to wait very much. In particular, when the apparatus automatically detects that color adjustment is necessary, the user waits for optimization or assurance as a manufacturer even though accuracy is not so required.

  Therefore, in this embodiment, the level 1 that matches the high accuracy is 3 minutes, the intermediate level is 90 seconds, the level 2 and the level 3 immediately after rushing are prepared, and the level required by the user is prepared. The three levels are automatically selected as appropriate in anticipation and the accuracy after adjustment.

  As an example of predicting the accuracy after adjustment, there is a paper type set at the time of color adjustment. If the paper loaded by the user at the time of color adjustment is other than the paper expected by the main body, it cannot be accurately adjusted because it is unknown whether the paper has changed due to different paper. Originally, in such an adjustment means, control is performed so as to correct an error from the case where ideal printing is performed on a sheet designated in advance by a manufacturer. Therefore, when a sheet other than the designated sheet is used, the color is changed. It cannot be adjusted. However, it is possible to estimate whether the paper is a predetermined paper by using an optical sensor as the paper detection sensor and estimating from the reflection amount or from the paper thickness. In this way, when the paper is other than the predetermined paper, it cannot be expected that it will match with high accuracy from the beginning even if the color is stabilized as described above. However, if the color adjustment means is selected, the user wants a reasonable color adjustment. Therefore, if it is detected that the paper is different from the designated paper, a warning that “the loaded paper is wrong” is displayed.

  In general, the user can select level 1 as level 2.

  By doing so, it was possible to optimize by automatically selecting or selecting at least part of the accuracy and time required by the user.

(Reading method of the second embodiment)
In the above embodiment, even one type of paper designated to be used for the color adjusting means can be implemented. However, when there are several types of designated sheets to be used by the color adjusting means, the optimization can be easily achieved by determining according to the sheets.

  One example thereof will be described with reference to FIG. In this embodiment, for simplification of description, the flow of printing and adjustment is the same as that in FIG. 1 described in the above embodiment. As described in the above embodiment, the time until the color stabilizes depends on the paper and humidity. Particularly in a high humidity environment, the time required for drying is relatively long. Therefore, in this embodiment, as shown in FIG. 5, the image forming apparatus is provided with a humidity sensor. When the humidity sensor is 70% RH or less, a normal humidity state is obtained. It was. As described in the above embodiment, the time from printing to measurement is provided in five stages from level 1 to level 5. Here, “immediately after level 5” means that reading is started immediately if it is in a state that can be read after patch printing without particularly controlling the time. In actual operation, since it is determined by the sequence operation time of the image forming apparatus, it is basically constant at any short time. After that, the time after the patch printing is shown, and all the patches are printed before the time as shown in FIG.

  In addition, five types of paper used for color adjustment are provided, and standard color parameters are prepared in advance for the designated paper used for each. In FIG. 5, the coated paper and the glossy paper have different color developability, so the prepared color parameters are different. However, regarding the control of the time until measurement after printing, the accuracy required for the application is almost the same as it is almost the same. I tried to control it.

  In addition, since plain paper does not require relatively high accuracy, it is not necessary to extend the time spent in an environment that requires time to stabilize, so the same is applied. However, since the colors that are stabilized even when the same density is read in different environments can be easily predicted to be different, it goes without saying that the correction amount is controlled to be different. Thus, as shown in FIG. 5, all the correction coefficients or methods for converting the correction amount from the read density are the same even if the level is the same.

In addition, proof paper as a paper often cares about color stabilization as an application. In this case, the paper is stabilized over time.
As described above, depending on the paper used for color adjustment, the use can be expected to be different. Therefore, it is possible to easily control to select the optimum accuracy and time spent for the use.

(Operation of Image Forming Apparatus of Third Embodiment)
Further, even if there is only one type of color adjusting means, if the application or paper to be used mainly and the paper are made known, optimization can be achieved by changing according to the information.

  An example will be described with reference to FIG. In this embodiment, level 1 to level 6 are set as shown. In this embodiment, the color adjustment is performed before the printing operation is executed after the user decides the printing operation before the printing operation. This tells you what kind of printing the user is trying to make color adjustments. The color adjustment paper at this time may be any one paper. If the paper specified for printing and the color adjustment paper are different, after determining the correction amount for the color adjustment paper, the correction amount is predicted for the paper used for printing and the color of the printing paper What is necessary is just to determine the correction amount with respect to conversion TBL.

  In FIG. 6, the level 6 is reached when the color adjustment paper is not designated paper, or when the paper set for printing is not designated paper. Level 6 has the same operation as level 5 in the above embodiment.

  In addition, when the printing paper is proof paper, basically, the time until measurement after printing is set to be relatively long to give priority to accuracy, but when the printing quality is selected as “fast”. Is based on level 5 because it can be assumed that speed is given priority over quality.

  In this way, when the paper to be printed is known in advance, it is easy to effectively change the level by controlling as in this embodiment.

  In addition to the control for automatically selecting the level as described above, the user can further specify the level by allowing the user to specify the level.

It is explanatory drawing of the flow used in the 1st Example of this invention. FIG. 3 is an elapsed time change in post-printing color for explaining the first embodiment of the present invention. FIG. It is an example of the elapsed time after printing explaining the 1st example of the present invention. It is the schematic explaining the multi scan of this invention. It is a printing ratio table of the image forming method used in the second embodiment of the present invention. It is explanatory drawing of the flow used in the 3rd Example of this invention. An example of an image forming apparatus provided with a copying machine type reading means. An example of an image forming apparatus provided with a reading sensor in a belt conveyance path. An example of an image forming apparatus provided with a serial scan type dedicated recording medium.

Explanation of symbols

1 recording head 1K black nozzle row 1C cyan nozzle row 1M magenta nozzle row 1Y yellow nozzle row X forward direction X ′ backward direction 50 recording medium

Claims (4)

  Data conversion means for converting to output data based on image data, image forming means for forming an image based on the output data, and an output result by the image forming means is not a desired output or is different from a desired output An adjustment unit that adjusts the data conversion unit when expected, and further selecting or predicting a desired output quality to determine a print mode and performing image formation by the image formation unit, An image forming apparatus comprising: an adjustment method selection unit that changes an adjustment method of the adjustment unit in accordance with the quality of the determined printing mode.   The adjustment method selection means means that at least the time required for the adjustment means, the number of operations, or the consumables to be consumed is reduced when the quality is low, or the adjustment accuracy is improved when the quality is high. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is one or both means for selecting an adjustment method.   Data conversion means for converting to output data based on image data, image forming means for forming an image based on the output data, and an output result by the image forming means is not a desired output or is different from a desired output An adjustment unit that adjusts the data conversion unit when expected, and an adjustment amount of the adjustment unit is an adjustment unit that determines the output of the adjustment pattern, the reading of the adjustment pattern, and the read value. In the apparatus, when the adjustment unit is executed, an output quality is selected or predicted to determine a print mode of the adjustment pattern, and when image formation is performed by the image forming unit, according to the determined print mode quality or paper type And changing the time interval from output to reading of the adjustment pattern of the adjustment means. .   4. The image forming apparatus according to claim 1, wherein the adjustment method is changed for each color.

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