JP5257781B2 - Printing device - Google Patents

Description

  The present invention relates to a printing apparatus.

  Dot size data stored in the database of the data processing device when printing a form having a fine dot pattern (hereinafter referred to as a “dot pattern”) that is read using an electronic pen (digital pen). A dot pattern is generated based on the print data, and the dot pattern is printed on the form by applying print data including the dot pattern, and the dot pattern in the form is read with a reader such as an electronic pen, and the read result is used. A technique for correcting the dot size data is known (see, for example, Patent Document 1).

JP 2007-279961 A

  The problem of the present invention is that the dot size is adjusted so that the dot size when an image including a dot pattern is printed out on a recording medium by a printing device is suitable for reading the dot pattern using an electronic pen or the like. It is in providing the technique which can correct | amend by.

  The invention described in claim 1 is a print output unit that prints an image on a recording medium using an image carrier, and an element that affects the dot size of a dot pattern printed on the recording medium by the print output unit. A detection unit that detects a value; a prediction unit that predicts a dot size when the dot pattern is printed on the recording medium based on the element value detected by the detection unit; and a prediction unit that is predicted by the prediction unit The present invention relates to a printing apparatus including correction means for obtaining a correction amount to be applied to a print output of an image including the dot pattern based on the predicted value of the dot size.

  According to a second aspect of the present invention, in the printing apparatus according to the first aspect, the correction unit corrects the correction amount so that a difference between the predicted value of the dot size and a preset target value of the dot size is reduced. Is what you want.

  According to a third aspect of the present invention, in the printing apparatus according to the first or second aspect, the detection means detects a time-dependent change value of the print output means as the element value.

  According to a fourth aspect of the present invention, in the printing apparatus according to the first or second aspect, the detection unit detects a printing environment value as the element value.

  According to a fifth aspect of the present invention, in the printing apparatus according to the first or second aspect, the detection unit includes a patch image including the dot pattern formed on the image holding body of the print output unit as the element value. The density value is detected.

  According to a sixth aspect of the present invention, in the printing apparatus according to the first or second aspect, the detection means detects a density value of a background portion of the dot pattern as the element value.

  According to a seventh aspect of the present invention, in the printing apparatus according to the first or second aspect, the correction unit obtains a correction amount of a print output condition applied to the printing of the dot pattern as the correction amount.

  According to an eighth aspect of the present invention, in the printing apparatus according to the first or second aspect, the correction unit obtains a correction amount of a dot size applied to the printing of the dot pattern as the correction amount.

  According to a ninth aspect of the present invention, in the printing apparatus according to the first or second aspect, the correction unit obtains a density correction amount of a dot pattern background portion applied to the printing of the dot pattern as the correction amount. is there.

  According to the invention described in claim 1, the dot size when the image including the dot pattern is printed out on the recording medium by the printing apparatus is adapted to the dot pattern reading using an electronic pen or the like. The size can be corrected by the printing device alone.

  According to the second aspect of the present invention, it is possible to print out a dot pattern on a recording medium with a dot size close to the target value as compared with the case without this configuration.

  According to the third aspect of the present invention, the dot size can be corrected in accordance with the temporal change of the print output means.

  According to the invention described in claim 4, the dot size can be corrected in accordance with the printing environment of the printing apparatus.

  According to the fifth aspect of the invention, the dot size can be corrected in accordance with the density of the patch image formed on the image carrier of the print output means.

  According to the invention described in claim 6, the dot size can be corrected in accordance with the density of the background portion of the dot pattern.

  According to the seventh aspect of the invention, the dot size of the dot pattern printed out on the recording medium can be changed by correcting the print output condition applied to the printing of the dot pattern.

  According to the eighth aspect of the invention, the dot size of the dot pattern printed out on the recording medium can be changed by correcting the dot size applied to the printing of the dot pattern.

  According to the ninth aspect of the present invention, the dot size of the dot pattern printed out on the recording medium can be changed by correcting the density of the dot pattern background portion applied to the printing of the dot pattern.

1 is a schematic configuration diagram of a printing system including a printing apparatus according to a first embodiment of the present invention. It is a figure which shows an example of a dot pattern. It is a figure which shows an example of the correlation data of the print number of prints, and dot size. It is a figure explaining the correlation of exposure light intensity and dot size. 3 is a flowchart showing a procedure of image printing processing performed by the printing apparatus according to the first embodiment of the present invention. 6 is a flowchart illustrating a procedure of correction amount generation processing performed by the printing apparatus according to the first embodiment of the present invention. It is a figure which shows an example of the correlation data of a density sensor reading value and dot size. It is a figure which shows the change of the dot size which arises by the difference in a background. It is a figure which shows an example of the correlation data of the density | concentration of a background part and dot size. It is a figure which shows the structural example of a density sensor. It is a figure which shows an example of the dot size applied to printing of a dot pattern. It is a figure which shows an example of the correlation data of the density | concentration of a dot pattern background part, and exposure light intensity.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. The technical scope of the present invention is not limited to the embodiments described below, and various modifications and improvements have been made within the scope of deriving specific effects obtained by the constituent requirements of the invention and combinations thereof. Also includes form.

<First Embodiment>
FIG. 1 is a schematic configuration diagram of a printing system including a printing apparatus according to a first embodiment of the present invention. The printing apparatus 1 is connected to a network 4 together with a plurality (two in the illustrated example) of terminal apparatuses 2 and 3. The terminal devices 2 and 3 are each configured using a personal computer or the like. The network 4 is configured using, for example, a LAN (Local Area Network) or the like. Here, the printing apparatus 1 and the terminal apparatuses 2 and 3 are connected via the network 4, but the present invention is not limited to this, and may be connected via a local interface capable of bidirectional communication (for example, a parallel port, a USB port, etc.). Good.

(Configuration of printing device)
The printing apparatus 1 includes a print control unit 10, a print image input unit 11, a page description language analysis unit 12, a print image drawing unit 13, a dot pattern detection unit 14, a print output unit 15, and an element value detection unit. 16, a dot size prediction unit 17, a print correction unit 18, and a storage unit 19.

  The print control unit 10 controls the overall processing and operation of the printing apparatus 1.

  The print image input unit 11 is for inputting image data for printing. In the present embodiment, it is assumed that image data for printing is transmitted from the terminal device 2 or the terminal device 3 to the printing device 1 via the network 4. In such a case, the print image input unit 11 inputs the print image by receiving the image data transmitted from the terminal device 2 or the terminal device 3. However, the input of the print image is not limited to transmission / reception of image data using the network 4, but may be performed by reading from a portable storage device such as a USB memory, for example.

  The page description language analysis unit 12 converts the image data into intermediate data (intermediate code) for generating a bitmap image by analyzing the image data for printing input by the print image input unit 11. is there.

  The print image drawing unit 13 draws (renders) a bitmap image from intermediate data obtained as an analysis result in the page description language analysis unit 12.

  The dot pattern detection unit 14 detects a dot pattern from the bitmap image by sequentially scanning and analyzing the bitmap image drawn by the print image drawing unit 13. A dot pattern is a dot image represented by a set of fine dots (dots). For example, the dot pattern detection unit 14 detects a dot pattern from a bitmap image by pattern matching processing using a reference dot pattern that defines a dot size and a dot interval of a dot pattern to be detected. As the reference dot pattern, for example, a known Anoto (registered trademark) dot pattern (see FIG. 2) may be used as a dot pattern for embedding information. In the pattern matching process, the similarity with the reference dot pattern is obtained, and a pattern having this similarity higher than a preset threshold is detected as a dot pattern.

  The print output unit 15 prints out the bitmap image drawn by the print image drawing unit 13 on a recording medium (such as paper) (not shown). The print output unit 15 prints out an image based on an electrophotographic system using an image carrier such as a photoconductor (photosensitive drum or the like) or a transfer body (intermediate transfer belt or the like). The image printing process based on the electrophotographic method includes a charging process, an exposure process, a development process, a transfer process, and a fixing process.

  The element value detection unit 16 detects an element value that affects the dot size of the dot pattern printed on the recording medium by the print output unit 15. The dot size of the dot pattern is a dimension representing the size (outer diameter) of each point constituting the dot pattern. Various elements are conceivable as elements that affect the dot size. In the present embodiment, the temporal change value of the print output unit 15 is detected as an example of the element value. The time-dependent change value of the print output unit 15 is a value that changes over time while the printing apparatus 1 is used, and particularly reflects a change in print characteristics of the print output unit 15.

  The element value detection unit 16 detects, for example, the cumulative number of prints of the recording medium as the temporal change value of the print output unit 15. The accumulated number of prints of the recording medium is counted by using an accumulation counter or the like so that one is added each time a recording medium on which an image is printed using the print output unit 15 is discharged from the main body of the printing apparatus. Is. In the case of a printing apparatus having a double-sided printing function, the accumulated number of prints is incremented by one each time an image for one page is printed. As the time-dependent change value of the print output unit 15, in addition to the cumulative number of prints, for example, a value obtained by integrating the exposure light source drive time (light emission time) or the rotation number of the photosensitive drum (or rotation drive time) is integrated. It is also possible to use values that have been adjusted.

  The dot size prediction unit 17 predicts the dot size when the dot pattern is printed on the recording medium (hereinafter also referred to as “dot size at the time of printing”) based on the element value detected by the element value detection unit 16. Is. As described above, when the value of the accumulated print number is used as the element value, the dot size prediction unit 17 predicts the dot size at the time of printing using the correlation data indicating the correlation between the accumulated print number and the dot size.

  The correlation data is data indicating how the dot size of the dot pattern that is actually printed on the recording medium changes with the change (increase) in the cumulative number of prints that accompanies the use of the printing apparatus. And obtained in advance by experiments or the like. The correlation data is stored in the storage unit 19 in advance. The dot size prediction unit 17 predicts the dot size at the time of printing by referring to the correlation data stored in the storage unit 19.

  FIG. 3 is a diagram showing an example of correlation data indicating the correlation between the accumulated print number and the dot size. In the illustrated correlation data, the horizontal axis represents the value of the accumulated print number, and the vertical axis represents the dimensional ratio (%) applied to dot size prediction. Even if the dot size of the dot pattern printed on the recording medium is printed by applying the same dot size data electronically, the components constituting the machine of the print output unit 15 (exposure device, photosensitive drum, transfer) It changes gradually (over time) due to wear of the belt. For this reason, in the correlation data shown in the figure, the dot size size ratio (%) gradually increases with the increase in the print cumulative number until the print cumulative number reaches 10,000. After the number of sheets reaches 10,000, the dimensional ratio of the dot size remains constant (100%).

  The print correction unit 18 obtains a correction amount to be applied to the print output of the image including the dot pattern, based on the predicted dot size predicted by the dot size prediction unit 17. An image including a dot pattern refers to an image including a dot pattern that is determined to have a similarity higher than a threshold value by comparison with a reference dot pattern set in advance (pattern matching processing) as described above. The print correction unit 18 obtains the correction amount so that the difference between the predicted dot size predicted by the dot size prediction unit 17 and a preset target dot size value is reduced.

  The target value of the dot size is set in advance based on the readability of a reader (such as an electronic pen) used for reading the dot pattern. For example, when a dot pattern printed on a recording medium is read by a reader, a target value is set in accordance with an intermediate value of a dot size range (readable range) that can be read by the reader. The target value of the dot size is stored in the storage unit 19 in advance. Therefore, the print correction unit 18 obtains the correction amount so that the difference between the predicted dot size predicted by the dot size prediction unit 17 and the target dot size value stored in the storage unit 19 becomes small. . The dot correction target value stored in the storage unit 19 may be read by the print correction unit 18 itself, or may be read by the print control unit 10 and notified to the print correction unit 18.

  The print correction unit 18 is configured to obtain a print output condition correction amount to be applied to dot pattern printing as the correction amount. There are various print output conditions. Here, as one of the print output conditions affecting the dot size, the correction amount of the exposure light intensity when forming the electrostatic latent image is obtained. The exposure light intensity is the intensity of exposure light output from a light source for exposure (for example, a semiconductor laser element). When the exposure light intensity is increased, the exposure amount increases accordingly, and when the exposure light intensity is decreased, the exposure amount decreases accordingly. As for the exposure light intensity, as shown in FIGS. 4A and 4B, when the exposure light intensity is relatively weak (when the exposure amount is relatively small), the exposure light intensity is relatively When the dot size of the dot pattern actually formed on the recording medium is compared when the intensity is increased (when the exposure amount is relatively increased), the dot size becomes larger when the exposure light intensity is increased.

  The print output condition that affects the dot size is not limited to the exposure light intensity (exposure amount) described above, and may be a development bias, for example. The developing bias is a voltage applied between the electrostatic latent image holding body that holds the electrostatic latent image and the developing device (developing electrode) when the electrostatic latent image is developed by the developing device. When the developing bias is increased, the electrostatic latent image is developed with more developer. For this reason, when printing the dot pattern by applying the same dot size data, the dot size at the time of printing becomes larger when the developing bias is increased.

  The storage unit 19 is used to store various data and information necessary for processing of the printing apparatus 1 including the correlation data for dot size prediction and the target value of the dot size. The storage unit 19 is configured using, for example, a nonvolatile storage element.

  FIG. 5 is a flowchart showing the procedure of the image printing process performed by the printing apparatus according to the first embodiment of the present invention. First, the print control unit 10 repeatedly checks whether or not there has been a print instruction from the terminal devices 2 and 3 (step S1). When it is determined that there is a print instruction from any one of the terminal devices (2, 3), the print image input unit 11 inputs the image data for printing designated as a print target by the print instruction (step S2). . The image data for printing is transmitted to the printing apparatus 1 in a PDL (page description language) format together with the printing instruction from the terminal apparatus that has issued the printing instruction to the printing apparatus 1. For this reason, the print image input unit 11 receives the image data for printing sent together with the print instruction in step S <b> 2 and takes it into the printing apparatus 1.

  Next, the page description language analysis unit 12 analyzes the print image data (PDL data) input by the print image input unit 11 in step S2, and generates intermediate data for drawing (step S3).

  Next, the print image drawing unit 13 draws the intermediate data generated by the page description language analysis unit 12 in step S3 on a bitmap image (step S4).

  Next, the dot pattern detection unit 14 performs a process of detecting a dot pattern from the bitmap image drawn by the print image drawing unit 13 in step S4 (step S5). As described above, the dot pattern detection unit 14 detects the dot pattern by the pattern matching process.

  Next, the print controller 10 confirms whether or not the dot pattern detector 14 has actually detected a dot pattern in the detection process of step S5 (step S6). If it is determined that a dot pattern has been detected, a correction amount generated by a correction amount generation process to be described later is acquired (step S7), and then the process proceeds to step S8. The correction amount generated by the correction amount generation process is stored in the storage unit 19. For this reason, the print control unit 10 reads and acquires the correction amount from the storage unit 19. If it is determined that no dot pattern has been detected, the process proceeds to step S8 without acquiring the correction amount.

  In step S8, the print output unit 15 prints out the bitmap image drawn by the print image drawing unit 13 in step S4 on a recording medium. At that time, when a dot pattern is included in the bitmap image (in other words, when the dot pattern detection unit 14 detects a dot pattern), the correction amount acquired by the print control unit 10 in step S7 is applied. An image including a dot pattern is printed out. Further, when the dot pattern is not included in the bitmap image (in other words, when the dot pattern detection unit 14 does not detect the dot pattern), the image is printed out without applying the correction amount.

  FIG. 6 is a flowchart showing a procedure of correction amount generation processing performed by the printing apparatus according to the first embodiment of the present invention. First, the print control unit 10 repeatedly checks whether or not the correction amount update time has come (step S11). If it is determined that it is time to update the correction amount, the element value detection unit 16 reads and detects the value (element value) of the accumulated print number from the accumulation counter or the like (step S12).

  Next, the dot size prediction unit 17 predicts the dot size when the dot pattern is printed on the recording medium based on the value of the accumulated print number detected by the element value detection unit 16 in step S12 (step S13). . The dot size is predicted using the correlation data shown in FIG. Specifically, the dimensional ratio (%) of the dot size corresponding to the value of the accumulated print number detected by the element value detection unit 16 is specified from the correlation data. Then, the dot size at the time of printing is predicted by multiplying the dimensional ratio of the specified dot size by, for example, the target value of the dot size read from the storage unit 19. For this reason, for example, when the target value of the dot size is 120 μm and the size ratio of the dot size specified from the correlation data is 90%, the dot size prediction unit 17 calculates “120 × 0.90”. Therefore, the dot size at the time of printing is predicted to be 108 μm.

  Next, the print correction unit 18 obtains a correction amount to be applied to the print output of the image including the dot pattern, based on the predicted dot size predicted by the dot size prediction unit 17 in step S13 (step S14). For example, when the predicted dot size value is 108 μm and the target dot size value is 120 μm as described above, the print correction unit 18 reduces the difference between them (ideally zero). Calculate the correction amount. If the target value of dot size is 120 μm and the predicted value of dot size is 108 μm, the difference between them is 12 μm. For this reason, the print correction unit 18 sets the correction amount to be applied to the printing of the dot pattern under the condition that the dot size when the dot pattern is actually printed on the recording medium is larger than the predicted dot size (108 μm). Ask.

  In the first embodiment, the print correction unit 18 obtains a correction amount of exposure light intensity that is one of print output conditions applied to dot pattern printing as the correction amount. In such a case, when the predicted dot size value is smaller than the target dot size value, the print correction unit 18 determines the exposure light intensity correction amount so that the exposure light intensity is stronger than the current print output conditions. Become. If the predicted dot size is larger than the target dot size, the print correction unit 18 determines the exposure light intensity correction amount so that the exposure light intensity is weaker than the current print output condition. .

  Next, the print control unit 10 stores the correction amount obtained by the print correction unit 18 in step S14 in the storage unit 19 (step S15). At this time, if the correction amount generated by the previous correction amount generation process is stored in the storage unit 19, it is stored in the storage unit 19 by rewriting it with the correction amount generated by the current correction amount generation process ( Update the correction amount to be set. The correction amount thus stored in the storage unit 19 is read out by the print control unit 10 in step S7 of the image printing process, and is applied to the print output of the image in the subsequent step S8.

  The timing for executing the correction amount generation process varies depending on the conditions under which the correction amount update timing is set. For example, when the correction amount update time is set at the time of executing the image printing process, the correction amount generation process is performed in parallel with the image printing process every time the above-described image printing process is performed. If the correction amount update time is set when the printing apparatus 1 is turned on, the correction amount generation process is performed in parallel with the warm-up process every time the printing apparatus 1 is turned on.

  If the process of step S12 is performed before the process of step S11, the correction amount update time may be determined based on the change amount of the element value with time. Specifically, the detection of the element value is repeatedly performed at a preset time interval. In addition, it is assumed that the element value used for the predicted dot size in step S13 is stored in the storage unit 19. Then, the print control unit 10 obtains a difference between the element value detected by the element value detection unit 16 at a certain timing and the element value stored in the storage unit 19 at that time, and the difference is set in advance as a reference value. Alternatively, the print control unit 10 may determine that it is time to update the correction amount.

  In the first embodiment, when the dot pattern detection unit 14 detects a dot pattern from the bitmap image developed using the print image data, the print control unit 10 corrects the correction amount. The image is printed out by applying the correction amount, but the present invention is not limited to this. For example, if the attribute information indicating that the image data for printing is image data including a dot pattern is added to the print instruction transmitted from the terminal device, this attribute information is added to the print instruction. If the print control unit 10 determines that the correction has been performed, the print control unit 10 may acquire a correction amount and apply the correction amount to print out an image.

<Second Embodiment>
The basic configuration of the printing apparatus 1 according to the second embodiment of the present invention is the same as that of the first embodiment (FIG. 1). However, the element value detected by the element value detection unit 16 is different from that in the first embodiment. That is, the element value detection unit 16 detects a printing environment value as an element value that affects the dot size of the dot pattern printed on the recording medium by the print output unit 15. The printing environment value is a value indicating the printing environment of the printing apparatus 1 and corresponds to, for example, values such as temperature and humidity. When detecting temperature and humidity as printing environment values, the element value detection unit 16 may be configured by a temperature sensor, a humidity sensor, or the like.

  The dot size prediction unit 17 uses correlation data indicating a correlation between temperature and dot size, correlation data indicating a correlation between humidity and dot size, or the like according to the type of element value detected by the element value detection unit 16. It is configured to predict the dot size during printing. Any correlation data is obtained in advance by experiments or the like and is stored in the storage unit 19 in advance. Note that the procedures of the image printing process and the correction amount generation process in the second embodiment and third to sixth embodiments to be described later are the same as those in the case of the first embodiment. Is omitted.

<Third Embodiment>
The basic configuration of the printing apparatus 1 according to the third embodiment of the present invention is the same as that of the first embodiment (FIG. 1). However, the element value detected by the element value detection unit 16 is different from that in the first embodiment. That is, the element value detection unit 16 detects the density value of the patch image including the dot pattern as an element value that affects the dot size of the dot pattern printed on the recording medium by the print output unit 15. The patch image is a test image formed on, for example, a transfer belt used as an image carrier when the print output unit 15 prints an image on a recording medium. In general, the patch image is formed for gradation correction of the print output unit 15. For this reason, a patch image for gradation correction may be formed as a dot pattern, and its density value may be detected as an element value, or a dedicated patch image may be formed for the purpose of correcting the dot size of the dot pattern. The density value may be detected as an element value. When the density value of the patch image is detected as an element value, the element value detection unit 16 may be configured by a density sensor.

  The dot size prediction unit 17 is configured to predict the dot size at the time of printing using correlation data indicating the correlation between the density value of the patch image and the dot size according to the type of element value detected by the element value detection unit 16. It has become. Basically, the density value of the patch image including the dot pattern formed on the image carrier is the same as the dot size of the dot pattern included in the patch image even if the same dot size data is applied to form the patch image. The larger it is, the higher it is (the density of the patch image is higher). Therefore, for example, when there is a correlation as shown in FIG. 7 between the sensor reading value and the dot size when the density of the patch image including the dot pattern is detected by the density sensor, the dot size prediction unit 17 performs the correlation. The dot size at the time of printing is predicted using the data. Therefore, for example, when the density value (sensor reading value) of the patch image detected by the element value detection unit (density sensor) 16 is 150, the dot size prediction unit 17 refers to the correlation data so as to perform printing. The dot size is predicted to be 103 μm.

<Fourth embodiment>
The basic configuration of the printing apparatus 1 according to the fourth embodiment of the present invention is the same as that of the first embodiment (FIG. 1). However, the element value detected by the element value detection unit 16 is different from that in the first embodiment. That is, the element value detection unit 16 detects the density value of the background portion of the dot pattern as an element value that affects the dot size of the dot pattern printed on the recording medium by the print output unit 15. The density value of the background part of the dot pattern may be detected by using a density sensor like the density value of the patch image described above, or the density value specified for the background part of the dot pattern in the image data for printing is used. You may read and detect.

  When a dot pattern is printed out on a recording medium using a printing apparatus that supports color printing, the dot size of the dot pattern formed thereon changes between a white background portion and a color background portion of the dot pattern. Specifically, when comparing the dot pattern formed on the white background portion with the dot pattern formed on the background portion of the color background, the dot pattern can be formed by applying the same dot size data. As shown in FIGS. 8A and 8B, the dot size of the white background is larger than that of the color background. The background portion of the color background refers to a background portion formed using at least one color developer among the three color developers (toner and the like) of yellow, magenta, and cyan. When a dot pattern is formed using a black developer on the background portion of such a color background, even if the dot pattern is formed by applying the same dot size data, the dot size of the dot pattern is the background. It depends on the concentration of the part. Specifically, the higher the density of the background portion of the color background (the greater the amount of developer in the background portion), the smaller the dot size of the dot pattern formed thereon.

  The dot size prediction unit 17 uses the correlation data indicating the correlation between the density value of the background portion of the dot pattern and the dot size according to the type of the element value detected by the element value detection unit 16, and determines the dot size at the time of printing. It is a configuration to predict. When a dot pattern having a white background portion and a dot pattern having a color background portion are mixed in one page of image data, the dot size prediction portion 17 determines the density value of each background portion. Predict the dot size when printing. In this case, if the predicted dot size predicted from the density value of the white background portion is deviated from the target value of the dot size, the print correction unit 18 obtains the correction amount so as to eliminate the deviation. Similarly, when the predicted dot size predicted from the density value of the background portion of the color background is deviated from the target value of the dot size, the print correction unit 18 obtains a correction amount so as to eliminate the deviation. For this reason, when printing an image containing a dot pattern with a white background and a dot pattern with a color background on a recording medium, it is applied depending on whether the background of the dot pattern is white or color. The correction amount is different.

  Further, the density of the dot pattern having the background portion of the color background varies depending on the area ratio (Cin) of the developer constituting the background portion of the dot pattern. For this reason, assuming that the density value of the background portion of the dot pattern is expressed by the sum of the developer area ratios of the three colors of yellow, magenta, and cyan (300% at the maximum), the dot size prediction unit 17 The dot size at the time of printing is predicted using correlation data indicating the correlation between the developer area ratio in the background portion and the dot size. For example, as shown in FIG. 9, correlation data used (referenced) for dot size prediction is yellow, magenta, cyan, and process black 3K (Y, Y) obtained by superimposing these three colors of developer. The correlation data indicating the correlation between the developer area ratio: Cin (%) of the background portion and the dot size may be stored in the storage unit 19 for each of the colors M, C).

  In the first to fourth embodiments, the element value that affects the dot size of the dot pattern printed on the recording medium by the print output unit 15 is the print output unit in the first embodiment. 15 are detected, the printing environment value is detected in the second embodiment, and the patch image including the dot pattern formed on the image holding member of the print output unit 15 in the third embodiment. Although the density value is detected and the density value of the background portion of the dot pattern is detected in the fourth embodiment, the element value detection unit 16 included in the printing apparatus 1 according to the present invention is included in each embodiment. Of the four corresponding element values, two or more element values (for example, a temporal change value and a printing environment value of the print output unit 15) may be detected.

  Further, when the density of the patch image including the dot pattern and the density of the background portion of the dot pattern are detected using the density sensor, as shown in FIG. It is preferable to use a density sensor 20 in which the optical sensors 22 are combined. The optical sensor 21 corresponding to the visible light region has a light emitting element 21a that emits light toward the transfer belt 23 on which the patch image is formed, and a light receiving sensitivity in the visible light region, and is emitted from the light emitting element 21a to be transferred to the transfer belt. And a light receiving element 21b that receives light reflected from the patch image on the image sensor 23. The optical sensor 22 corresponding to the infrared region has a light emitting element 22a that emits light toward the transfer belt 23 on which the patch image is formed, and has a light receiving sensitivity in the infrared region, and is emitted from the light emitting element 22a to be on the transfer belt 23. And a light receiving element 22b for receiving light reflected from the patch image.

  When the density sensor 20 having the above configuration is used, as shown in FIG. 10A, the density of a patch image formed for tone correction using a developer of each color of yellow Y, magenta M, and cyan C. Alternatively, the density of the background portion (color background) of the dot pattern formed using the black K developer may be detected by the optical sensor 21 corresponding to the visible light region. Further, as shown in FIG. 10B, when the background portion of the dot pattern is a color background and the dot pattern is formed thereon using a black K developer, the dots of the dot pattern The density of the patch image for predicting the size may be detected by the optical sensor 22 corresponding to the infrared region. Incidentally, the yellow, magenta, and cyan color developers used in printing do not absorb infrared light, and the black developer has characteristics of absorbing infrared light.

<Fifth embodiment>
The basic configuration of the printing apparatus 1 according to the fifth embodiment of the present invention is the same as that of the first embodiment (FIG. 1). However, the amount of correction required by the print correction unit 18 is different from that of the first embodiment. That is, the print correction unit 18 obtains a dot size correction amount to be applied to dot pattern printing as a correction amount to be applied to print output of an image including a dot pattern. The dot size applied to the dot pattern printing is set according to the dot size data stored in the storage unit 19 in advance. The dot size data is data that designates the dot size with, for example, an m × n pixel configuration. Since the minimum pixel size is common, the dot size specified by the m × n pixel configuration increases as the values of m and n increase. Therefore, for example, as shown in FIGS. 11A and 11B, when the dot size specified by the 2 × 2 pixel configuration is compared with the dot size specified by the 3 × 3 pixel configuration, the latter The dot size is larger than the former.

  Accordingly, when printing the image on the recording medium by applying the correction amount of the dot size obtained by the print correction unit 18, the print control unit 10 changes the dot size data itself stored in the storage unit 19, or The dot size data read from the storage unit 19 is changed, the changed dot size data is applied, and the print output unit 15 executes print output of the image. Thereby, when the dot size indicated by the dot size data after the change is larger than the dot size indicated by the dot size data before the change, the dot pattern is exposed so that the dot size becomes larger than before the change. . Conversely, when the dot size indicated by the dot size data after the change is smaller than the dot size indicated by the dot size data before the change, the dot pattern is exposed so that the dot size becomes smaller than before the change. .

<Sixth Embodiment>
The basic configuration of the printing apparatus 1 according to the sixth embodiment of the present invention is the same as that of the first embodiment (FIG. 1). However, the amount of correction required by the print correction unit 18 is different from that of the first embodiment. That is, the print correction unit 18 obtains the density correction amount of the dot pattern background portion to be applied to the printing of the dot pattern as the correction amount to be applied to the print output of the image including the dot pattern. As described above, as the density of the dot pattern background increases, the dot size of the dot pattern formed thereon decreases. For this reason, if the predicted dot size is larger than the target value for dot size, the density correction amount is calculated under the condition that the density of the dot pattern background is high, and the predicted dot size is greater than the target value for dot size. Is smaller, the density correction amount is obtained under the condition that the density of the dot pattern background is low.

Accordingly, assuming that the density correction amount of the dot pattern background portion is expressed by a value (300% at maximum) obtained by adding the developer area ratio (Cin) of each color of yellow, magenta, and cyan, the print control unit 10 From the developer area ratios (Cin) for the three colors obtained by the print correction unit 18 as the density correction amount of the dot pattern background portion, the exposure light intensity applied to the dot pattern exposure is determined. For example, when the three-color developer area ratio (total) obtained by the print correction unit 18 as the density correction amount of the dot pattern background portion is 210%, the print control unit 10 uses the correlation data shown in FIG. The exposure light intensity is determined to be 2.0 (nJ / mm ² ).

  In the first embodiment, the correction amount of the print output condition (exposure light intensity) applied to the printing of the dot pattern is obtained as the correction amount applied to the print output of the image including the dot pattern. In the fifth embodiment, the correction amount of the dot size applied to the dot pattern printing is obtained. In the sixth embodiment, the density correction amount of the dot pattern background portion applied to the dot pattern printing is obtained. However, the print correction unit 18 may obtain two types of correction amounts arbitrarily selected from the three types of correction amounts or all three types of correction amounts. For example, when two types of correction amounts are obtained, a correction ratio may be allocated to each correction amount at a ratio of 50% and the other correction amount at 50%.

  In the first to sixth embodiments, when an image including a dot pattern is printed by applying the correction amount obtained by the print correction unit 18, dots in the image area of the bitmap image are printed. An area where a pattern exists and an area where a dot pattern does not exist are discriminated by the dot pattern detection unit 14, and based on the discrimination result, printing is performed by applying the correction amount only to an area where a dot pattern exists. In addition, the print control unit 10 may control the print output unit 15.

  DESCRIPTION OF SYMBOLS 1 ... Printing device, 2, 3 ... Terminal device, 4 ... Network, 10 ... Print control part, 11 ... Print image input part, 12 ... Page description language analysis part, 13 ... Print image drawing part, 14 ... Dot pattern detection part , 15 ... print output unit, 16 ... element value detection unit, 17 ... dot size prediction unit, 18 ... print correction unit, 19 ... storage unit

Claims (9)

Print output means for printing out an image on a recording medium using an image carrier;
Detecting means for detecting a density value of a background portion of the dot pattern as an element value affecting the dot size of the dot pattern printed on the recording medium by the print output means;
Predicting means for predicting the dot size when the dot pattern is printed on the recording medium, based on the element value detected by the detecting means;
And a correction unit that obtains a correction amount to be applied to a print output of an image including the dot pattern based on the predicted value of the dot size predicted by the prediction unit. The correction means obtains the correction amount so that a difference between the predicted dot size value and a preset dot size target value is small.
The printing apparatus according to claim 1 . The correction means obtains a density correction amount of a dot pattern background portion applied to the printing of the dot pattern as the correction amount.
The printing apparatus according to claim 1 or 2. The correction means obtains a correction amount of a print output condition applied to the printing of the dot pattern as the correction amount.
The printing apparatus according to claim 1 . The correction means obtains a dot size correction amount to be applied to the printing of the dot pattern as the correction amount.
The printing apparatus according to claim 1 . Print output means for printing out an image on a recording medium using an image carrier;
Detecting means for detecting an element value that affects a dot size of a dot pattern printed on the recording medium by the print output means;
Predicting means for predicting the dot size when the dot pattern is printed on the recording medium, based on the element value detected by the detecting means;
Based on the predicted value of the dot size predicted by the prediction means, the correction amount of the dot pattern background portion applied to the printing of the dot pattern is used as the correction amount applied to the print output of the image including the dot pattern. And a correction device to obtain . The detection means detects a time-dependent change value of the print output means as the element value.
The printing apparatus according to claim 6 . The detection means detects a printing environment value as the element value.
The printing apparatus according to claim 6 . The detection unit detects a density value of a patch image including the dot pattern formed on the image holding body of the print output unit as the element value.
The printing apparatus according to claim 6 .

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