JP2009016937A - Image forming apparatus and control method of image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which embeds a digital watermark of high detectability while maintaining ink discharge performance and detects the digital watermark information precisely. <P>SOLUTION: In order to maintain high discharge performance of a recording element, a preliminary discharge data adding means adds data for discharging ink preliminarily from the recording element to a recording medium. A means for embedding a digital watermark is also provided. A duplicate processing prevention means prevents a preliminary discharge permission region and a digital watermark embedding region from being processed in duplicate. The preliminary discharge permission region is a region where the preliminary discharge data adding means is allowed to add the preliminary discharge data to the recording medium, and the digital watermark embedding region is a region where the digital watermark embedding means embeds of the digital watermark. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a control technique for embedding a digital watermark in an image forming apparatus employing an ink jet method.

  In recent years, the distribution of digital data has increased along with the worldwide spread of networks. Under such circumstances, digital watermarks are attracting attention from the viewpoint of copyright protection and the like. “Digital watermark” is a technique for embedding information in digital data so that it cannot be perceived by humans.

  As a method for embedding a digital watermark in an image, there are a method for replacing low-order bits of an image with digital watermark information, a method for embedding after performing frequency conversion, and the like. These methods are embedded so that it is difficult for humans to perceive.

  This digital watermark is effectively used by embedding copyright information, history management, and the like when buying and selling electronic content data. For this reason, a popular low-priced printer, digital camera, and the like are also required to have a digital watermark function.

  In recent years, printers using an ink jet system that forms an image by ejecting liquid have become widespread as popular low-cost printers. This apparatus forms an image by injecting ink into a thin nozzle and ejecting the ink onto a recording medium. As a method of ejecting ink, there are a method of ejecting ink droplets by expanding moisture in the ink by applying heat, a method of ejecting ink droplets using a piezo element that expands and contracts by application of voltage, and the like.

  The nozzles of the ink discharge section of such an image forming apparatus have a very fine configuration in order to improve image quality. For this reason, there is a problem in that a discharge failure occurs due to adhesion of foreign matter and dyes or pigments used as ink.

As a countermeasure against such a problem, a technique for preliminarily ejecting a nozzle with a small number of ejections on a recording medium during recording to an inconspicuous image is disclosed (for example, see Patent Documents 1, 2, and 3). . Such preliminary ejection onto the recording medium is referred to as “paper preliminary ejection” in this specification.
JP-A-55-139269 JP-A-6-40042 JP-A-2005-161615

  However, in order to maintain such print quality, in an image forming apparatus that performs preliminary paper ejection, if the digital watermark process and the paper preliminary ejection process are performed in duplicate, the detectability may decrease. .

The present invention provides an image forming apparatus and an image processing apparatus control method capable of embedding highly-detectable digital watermarks while maintaining ink ejection performance, and thus accurately detecting digital watermark information. The purpose is to do.

The present invention is an ink jet type image forming apparatus in which an image is formed on a recording medium by ejecting ink by a recording element. In addition, the present invention provides a preliminary ejection in which preliminary ejection data for preliminarily ejecting ink from the recording element to the recording medium is added to the print image data in order to maintain good ejection performance of the recording element. Data adding means is included. Furthermore, the present invention includes a digital watermark embedding unit that embeds a digital watermark. In addition, the present invention includes an overlapping process preventing unit that prevents the preliminary ejection permission area and the digital watermark embedding area from being processed in an overlapping manner. The preliminary ejection permission area is an area where the preliminary ejection data adding means is permitted to add the preliminary ejection data to the recording medium, and the digital watermark embedding area is an electronic watermark embedding means. This is an area for executing processing for embedding a watermark.

According to the present invention, since the area in which the digital watermark information is embedded and the area in which preliminary ejection is performed are separated, it is possible to embed a highly detectable digital watermark while maintaining ink ejection performance. It is possible to detect the above with high accuracy.

  The best mode for carrying out the invention is the following embodiment.

  FIG. 1 is a block diagram showing an image forming apparatus PR1 that is Embodiment 1 of the present invention.

  The image forming apparatus PR1 is connected to the host PC 190.

  The image forming apparatus PR1 includes a controller unit 10, an operation panel unit 31, a head unit 32, a carriage motor unit 33, and a paper conveyance motor unit 34.

  The operation panel unit 31 includes an LCD, an LED, and a switch, and is used by the user to set the image forming apparatus PR1 and check the state of the image forming apparatus PR1. The head unit 32 performs control for forming an image. The carriage motor unit 33 performs an operation of a carriage described later on which the head unit 32 is mounted. The paper transport motor unit 34 transports the paper P to be printed.

  The controller unit 10 performs electrical control of the image forming apparatus PR1. The controller unit 10 includes a CPU 11, an interface control unit 12, a ROM 13, a RAM 14, an EEPROM 15, an operation panel control unit 16, and an image processing unit 17. In addition, the image forming apparatus PR1 includes a head control unit 18, a carriage motor control unit 19, and a paper transport motor control unit 20.

  The CPU 11 controls the image forming apparatus PR1. The interface control unit 12 connects to the host PC 190 and controls communication. The ROM 13 stores a program for controlling the printer. The RAM 14 is a data readable / writable memory. The EEPROM 15 is a memory that can hold data even when the power is shut off.

  The operation panel control unit 16 controls communication with the operation panel unit 31. The head control unit 18 controls the head unit 32. The carriage motor control unit 19 controls the carriage motor unit 33. The paper transport motor control unit 20 controls the paper transport motor unit 34.

  In the embodiment in the present specification, the image forming apparatus PR1 is directly connected to the host PC 190, but the image forming apparatus PR1 may be connected to the host PC 190 via a network. The present invention is effective regardless of the form of connection with the host PC 190.

  The image processing unit 17 is an example of a processing unit having functions of a digital watermark embedding unit, a preliminary ejection data adding unit, and a duplication processing preventing unit. However, it is not necessary to limit the processing unit including the digital watermark, and for example, the CPU 11 may embed the digital watermark by software control.

  FIG. 2 is a diagram illustrating an image forming method in the image forming apparatus PR1.

  The paper P is an example of a recording medium. Instead of the paper P, a recording medium such as a cloth or a film may be used.

  The carriage unit 40 mounts the head unit 32. The carriage motor shaft 41 is an axis of operation in the main scanning direction in the control of the carriage motor. The carriage motor bearings 42 are provided at both ends of the carriage motor shaft 41 so that the carriage motor operates with high accuracy.

  When the timing belt 43 operates, the carriage unit 40 operates. The timing belt rotation shaft 44 operates the timing belt 43 under the rotation control of the carriage motor unit 33. The timing belt fixing shaft 45 restricts the timing belt to operation only in the rotation direction, and the timing belt rotation shaft 44 rotates to operate the carriage unit 40.

  The paper transport motor shaft 51 rotates under the control of the paper transport motor unit 34. The paper transport motor bearing 52 is provided in order to restrict the paper transport motor shaft 51 only in the rotation direction and perform paper transport with high accuracy. The paper transport roller 53 is provided in connection with the paper transport motor shaft 51, transmits the rotation operation of the paper transport motor shaft to the paper P, and operates the paper P in the sub-scanning direction.

  Next, the printing operation in Example 1 will be described.

  The carriage unit 40 is normally present at the home position. During the printing operation, the carriage is operated in the main operation direction, and the paper P is operated in the sub operation direction. The head unit 32 forms an image by ejecting appropriate ink droplets at appropriate positions.

  FIG. 3 is a diagram illustrating a printing process in image formation in the first embodiment.

  FIG. 3A is a diagram illustrating a state before the printing operation. The head unit 32 is in a standby state at the upper left of the paper P. FIG. 3B is a diagram illustrating a state during the printing operation of the first pass. Ink droplets are ejected from the head and the head is moved in the main scanning direction.

  FIG. 3C is a diagram illustrating a state when the printing operation for the first pass is completed. FIG. 3D shows the state before the paper P is fed and before the second pass printing operation. By transporting the paper P in the sub-scanning direction, the position of the head relative to the paper P moves. Here, in the case of the image forming apparatus PR1 capable of reciprocal printing, the head unit 32 performs printing from the position shown in FIG. If the printer does not have a reciprocating printing function, the same operation as described above is performed in the main scanning direction after returning to the position shown in FIG.

  Next, a description will be given of dot arrangement when normal paper surface preliminary ejection is performed.

  FIG. 4 is a diagram for explaining dot arrangement when preliminary ejection is performed on the paper P in the first embodiment.

  The grids in FIG. 4 are pixels obtained by binarizing the image data, and the black area indicates dots arranged on the paper P. Black grids indicate dot positions where preliminary ejection is performed, and white grids indicate dot positions where preliminary ejection is not performed. The origin P1 of the dot position where the preliminary ejection is performed is expressed as coordinates (0, 0). From the origin P1, the coordinate value increases as it goes to the right in the main scanning direction, and the coordinate value increases as it goes down in the sub-scanning direction. A dot moved from the origin P1 in the main scanning direction by X and by Y in the sub scanning direction is expressed as (X, Y).

  In the case of the example shown in FIG. 4, preliminary discharge is performed on the origin P1. Further, preliminary discharge is performed also on the coordinates (6, 1) of the position P2 which has moved 6 dots in the X direction from the origin P1 and moved 1 dot in the Y direction. Similarly, preliminary ejection is performed also on the coordinates (12, 2) of the position P3 which has moved 6 dots in the X direction from the position P2 and moved 1 dot in the Y direction. The same applies to the position P4.

  In this way, by arranging dots at intervals in the X direction, the dots are dispersed and made inconspicuous. In addition, by disposing one dot at a time in the Y direction, preliminary ejection can be performed with all nozzles.

  FIG. 5 is a diagram illustrating that the area in which the digital watermark is embedded and the preliminary ejection portion are arranged so as not to overlap in the first embodiment.

  The hatched area is a digital watermark embedding area, and the black area is a preliminary discharge location. In this way, the arrangement and control are performed so that the digital watermark embedding area and the preliminary ejection portion do not overlap.

  In the first embodiment, prior to the digital watermark embedding process and the preliminary ejection data adding process, the process is divided into areas to be processed. The image forming apparatus PR1 that is Embodiment 1 is an apparatus that performs preliminary ejection at a constant rate regardless of image data.

  FIG. 6 is a flowchart for performing the digital watermark embedding process and the preliminary ejection process in the first embodiment.

  First, in S1, the area dividing means realized by the CPU 11 divides the area of the paper P into a digital watermark embedding area and a preliminary ejection permission area. In S2, the digital watermark embedding means realized by the CPU 11 embeds the digital watermark in the digital watermark embedding area. In S3, the preliminary ejection data adding means realized by the CPU 11 performs preliminary ejection at a necessary location in the preliminary ejection permission area. The above process is performed and the process ends.

  Next, each process will be described in detail.

  FIG. 7 is a diagram illustrating an example in which the area dividing unit divides the area in the first embodiment.

  In FIG. 7, the hatched area is a digital watermark embedding area, and the white area is a preliminary ejection permission area. The “digital watermark embedding area” is an area where processing for embedding a digital watermark is performed. The “preliminary ejection permission area” is an area where preliminary ejection processing may be performed. Preliminary ejection needs to be performed within a certain period. For this reason, as shown in FIG. 7, it is necessary to disperse and arrange preliminary ejection permission areas.

  The numbers described in FIG. 7 are area numbers, which are numbers indicating the order of processing in the first embodiment. The processing is started from the area of area number “1” described in the upper left corner, and sequentially in the right direction. When processing of this line is completed, processing is performed on the next lower line. This process is repeated and finally the process is performed up to the lower right corner area.

  FIG. 8 is a flowchart illustrating the digital watermark embedding process performed by the digital watermark embedding unit in the first embodiment.

  In S11, the area number X is initialized. In S12, the region number X is added. In S13, it is determined whether or not the area of area number X is a digital watermark embedding area. If it is an electronic watermark embedding area, an electronic watermark embedding process is performed in S14, and the process proceeds to S15. If it is not a digital watermark embedding area, it is determined in S15 whether the processing area is the last area. If it is the last processing area, the digital watermark embedding process is terminated. If it is not the last processing area, the process returns to S12.

  FIG. 9 is a flowchart illustrating the operation of adding preliminary ejection data in the first embodiment.

  When the preliminary ejection data addition process is started, the area number X is initialized in S21. In S22, the region number X is added. In S23, it is determined whether or not the area of area number X is a preliminary ejection permission area. If it is the preliminary ejection permission area, preliminary ejection data addition processing is performed in S24, and the process proceeds to S25. If it is not the preliminary ejection permission area, it is determined in S25 whether or not the processing area is the last area. If it is the last processing area, the preliminary ejection data adding process is terminated. If it is not the last processing area, the process returns to S22.

  FIG. 10 is a diagram illustrating an example of a processing result in the first embodiment.

  In FIG. 10, the hatched area is a digital watermark embedding area, the white area is a preliminary ejection permission area, and the black area is a preliminary ejection location.

  By executing the control operations shown in FIGS. 6 to 9, it is possible to control the electronic watermark embedding area and the preliminary ejection portion so as not to overlap each other.

(Modification of Example 1)
In the first embodiment, the preliminary ejection data adding process is executed after the area is divided and the digital watermark process is performed. In the modification of the first embodiment, the digital watermark embedding process and the preliminary ejection data addition process are executed in parallel, the next process is determined according to the processing area, and the digital watermark embedding process or the preliminary ejection data addition process is executed. This is an example.

  FIG. 11 is a flowchart illustrating a digital watermark embedding process and a preliminary ejection process in a modification of the first embodiment.

  In S31, the area dividing unit divides the area into a digital watermark embedding area and a preliminary ejection permission area. In step S32, the digital watermark embedding unit performs a digital watermark embedding process for the area designated as the digital watermark embedding area. For the area designated as the preliminary ejection permission area, in S33, the preliminary ejection data adding means performs preliminary ejection at a necessary position in the preliminary ejection permission area. The above process is performed and the process ends.

  FIG. 12 is a flowchart illustrating a specific processing procedure in a modification of the first embodiment.

  In S41, the region number X is initialized, and in S42, the region number X is added. In S43, it is determined whether the area of area number X is a digital watermark embedding area. If it is a digital watermark embedding area, a digital watermark embedding process is performed in S44. If it is not a digital watermark embedding area, preliminary ejection data addition processing is performed in S45. In S46, it is determined whether or not the processing area is the last area. If it is the last processing area, the digital watermark embedding process and the preliminary ejection data adding process are terminated. If it is not the last processing area, the process returns to S42.

As a result of performing the processing shown in FIGS. 11 and 12, the same result as the processing shown in FIG. 10 can be obtained.

  The image forming apparatus PR2, which is Embodiment 2 of the present invention, is an embodiment that performs processing for embedding a digital watermark while avoiding a place where preliminary ejection is performed.

  The configuration of the image forming apparatus PR2 is basically the same as the configuration of the image forming apparatus PR1 shown in FIGS. Assume that the image forming apparatus PR2 is a device that performs preliminary ejection at a constant rate regardless of image data.

  FIG. 13 is a flowchart for performing the digital watermark embedding process and the preliminary ejection process in the second embodiment.

  In S51, the preliminary ejection data adding means adds preliminary ejection data. In S53, the preliminary ejection area avoiding means realized by the CPU 11 designates the area other than the area where preliminary ejection is performed as the digital watermark embedding area. In S52, the digital watermark embedding unit realized by the CPU 11 determines the digital watermark embedding area based on the information of the digital watermark embedding unit, and performs the digital watermark embedding process. The above process is performed and the process ends.

  FIG. 14 is an explanatory diagram of an operation in which the preliminary ejection region avoiding unit designates a region in the second embodiment.

  FIG. 14A is a diagram illustrating image data to which preliminary ejection data is added in the second embodiment. FIG. 14B is a diagram illustrating image data in which digital watermark information is embedded while avoiding the preliminary ejection area in the second embodiment.

  In the state shown in FIG. 14A, as shown in FIG. 4, the preliminary discharge portions are arranged in a distributed manner. In the state shown in FIG. 14B, the area designated by the preliminary ejection area avoiding means as the digital watermark embedding area is an area indicated by hatching. As shown in FIG. 14B, the digital watermark embedding area is designated avoiding the preliminary ejection point.

  FIG. 15 is a flowchart illustrating a digital watermark embedding process procedure by the digital watermark embedding unit in the second embodiment.

  First, X is used as an area number for distinguishing areas. In S61, the area number X is initialized. In S62, the region number X is added. In S63, it is determined whether or not the area indicated by the area number X is a digital watermark embedding area. If it is an electronic watermark embedding area, an electronic watermark embedding process is performed in S64, and the process proceeds to S65. If it is not the digital watermark embedding area, it is determined in S65 whether the processing area is the last area. If it is the last processing area, the digital watermark embedding process is terminated. If it is not the last processing area, the process returns to S62.

As a result of performing the above processing flow, it is possible to control so that the digital watermark embedding area and the preliminary ejection portion do not overlap.

  The image forming apparatus PR3, which is Embodiment 3 of the present invention, is an embodiment that performs a process of predicting a place to perform preliminary ejection and embedding a digital watermark.

  The configuration of the image forming apparatus PR3 is basically the same as the configuration of the image forming apparatus PR1 shown in FIGS. The image forming apparatus PR3 is a device that controls preliminary ejection according to image data and performs preliminary ejection when “0” continues as a data value.

  FIG. 16 is a flowchart illustrating the digital watermark embedding process and the preliminary ejection process in the third embodiment.

  In S71, the digital watermark embedding unit realized by the CPU 11 embeds the digital watermark. The preliminary ejection area prediction means realized by the CPU 11 predicts an area where preliminary ejection is performed in S72. As a result of this prediction, an area where preliminary ejection is not performed is assumed to be an electronic watermark embedding area, and this information is transmitted to the electronic watermark embedding means. The digital watermark embedding unit embeds a digital watermark only in a digital watermark embedding area. In S73, the preliminary ejection data adding means realized by the CPU 11 performs preliminary ejection at a necessary location in the preliminary ejection permission area. The above process is performed and the process ends.

  FIG. 17 is a diagram illustrating a prediction operation performed by the preliminary ejection region prediction unit in the third embodiment.

  FIG. 17A shows an original image. FIG. 17B is a diagram showing an image in which a digital watermark embedding area is designated.

  In FIG. 17A, there is a white data area in the image data. The image forming apparatus PR3 according to the third embodiment controls the preliminary ejection according to the image data, and predicts that the preliminary ejection processing is performed in an area where the data value “0” continues.

  In FIG. 17B, the hatched area is a digital watermark embedding area, and the white area is a preliminary ejection permission area. In the area where the data value “0” continues, it is predicted that the preliminary ejection process will be performed. Therefore, the area other than this area is designated as the digital watermark embedding area.

  In the third embodiment, preliminary ejection is performed when “0” continues as an image data value. However, preliminary ejection is performed by another control method, a region where preliminary ejection is performed is predicted, and an electronic watermark is embedded while avoiding this region. You may do it.

  FIG. 18 is a flowchart illustrating an operation of the digital watermark embedding unit performing digital watermark embedding processing in the third embodiment.

  X is an area number for distinguishing areas. An electronic watermark embedding process is started, and an area number X is initialized in S81. In S82, the region number X is added. In S83, it is determined whether or not the area indicated by the area number X is a digital watermark embedding area. If it is an electronic watermark embedding area, an electronic watermark embedding process is performed in S84, and the process proceeds to S85. If it is not a digital watermark embedding area, it is determined in S85 whether or not the processing area is the last area. If it is the last processing area, the digital watermark embedding process is terminated. If it is not the last processing area, the process returns to S82.

  FIG. 19 is a diagram illustrating a result of performing processing for predicting a place where preliminary ejection is performed and embedding a digital watermark in the third embodiment.

  Preliminary ejection is performed in the preliminary ejection permitted area of image data, and preliminary ejection is not performed in the digital watermark embedding area.

As a result of performing the above processing, it is possible to control so that the digital watermark embedding area and the preliminary ejection portion do not overlap.

  The image forming apparatus PR4, which is Embodiment 4 of the present invention, is a method for performing a process of adding preliminary ejection data while avoiding the digital watermark embedding area.

  The configuration of the image forming apparatus PR4 is basically the same as the configuration of the image forming apparatus PR1 shown in FIGS. The image forming apparatus PR4 is an apparatus that performs preliminary ejection at a constant rate regardless of image data.

  FIG. 20 is a flowchart showing operations for performing the digital watermark embedding process and the preliminary ejection process in the fourth embodiment of the present invention.

  In S91, the digital watermark embedding means realized by the CPU 11 embeds the digital watermark. In S93, the digital watermark embedding area avoiding means realized by the CPU 11 designates the area other than the area where the digital watermark is embedded as the preliminary ejection permission area. In S92, the preliminary ejection data adding unit realized by the CPU 11 performs preliminary ejection at a necessary position in the preliminary ejection permission area based on the information of the digital watermark embedding area avoiding unit. The above process is performed and the process ends.

  FIG. 21 is a diagram for explaining a digital watermark data embedding method in the fourth embodiment.

  In FIG. 21, the hatched area is a digital watermark embedding area, and the white area is a preliminary ejection permission area.

  As shown in FIG. 21, the digital watermark is embedded without laying out the digital watermark embedding area while sandwiching the preliminary ejection permission area. The reason why the digital watermark embedding area is arranged with the preliminary ejection permission area in between is because it is necessary to perform preliminary ejection within a certain period.

  FIG. 22 is a diagram illustrating a normal preliminary ejection data adding method in the fourth embodiment.

  The grids in FIG. 22 are pixels obtained by binarizing the image data, and the black area indicates dots arranged on the paper P. As in the areas 61 to 64, the dots are dispersed and made inconspicuous by arranging the dots at intervals in the X direction. In addition, by disposing one dot at a time in the Y direction, preliminary ejection can be performed with all nozzles. Further, since the preliminary ejection needs to be performed within a certain period, even if the nozzle has performed preliminary ejection in the region 61, it is necessary to perform preliminary ejection again in the region 65 after the set ejection cycle.

  FIG. 23 is a diagram for explaining a normal preliminary ejection data adding method for each line in the fourth embodiment.

  The preliminary discharge addition process for the first line will be described.

  Ct is a discharge period, and Cs is a pixel counter initial value. If the discharge cycle is 17 pixels and there are no restrictions, preliminary discharge is performed every 17 pixels. A pixel counter C is used for preliminary ejection every 17 pixels. The pixel counter C counts every time a pixel is processed. When the count value of the pixel counter C coincides with the ejection cycle, preliminary ejection data is added and the count value is cleared. These processes are repeated until the end of the line.

  Since the initial value of the count value of the pixel counter C is dispersed in the main scanning direction, it differs for each line. In particular, the adjacent counters C are preferably arranged so that the preliminary discharge pixels are aligned when the initial values match, so that the initial values do not match.

  FIG. 24 is a diagram for explaining the operation of adding preliminary ejection data while avoiding the digital watermark embedding area in the fourth embodiment.

  FIG. 24A is a diagram showing normal preliminary ejection data. FIG. 24B is a diagram showing preliminary ejection data when processing for avoiding the digital watermark embedding area is performed.

  In FIG. 24A, the preliminary ejection data 71 exists in the digital watermark embedding area. In FIG. 24B, the preliminary discharge data 72 is moved to the dot position 73 in the preliminary discharge permission area. By controlling in this way, it is possible to control so that the digital watermark embedding area and the preliminary ejection portion do not overlap.

  FIG. 25 is a flowchart illustrating processing of the preliminary ejection data adding unit in the fourth embodiment.

  In S101, the pixel counter C is initialized with the value set as the pixel counter initial value Cs. In S102, the pixel moves to the next pixel to be processed, and the pixel counter C is added. In S103, it is determined whether or not the processing line has been completed. When the processing line ends, the process proceeds to S109. If the processing line has not ended, in S104, the process is compared with the ejection cycle Ct. If the pixel counter C does not coincide with the ejection cycle Ct, the process returns to S102 and the same processing is performed.

  If the pixel counter C coincides with the ejection cycle Ct, the pixel counter C is cleared in S105. In S106, it is determined whether it is a preliminary discharge permission area. If it is not the preliminary ejection permission area, in S107, the pixel counter C is incremented at the same time as moving to the next pixel, the process returns to S106, and the same processing as described above is performed.

  If it is a preliminary discharge permission area, preliminary discharge data is added in S108, and the process returns to S102 and the same processing is performed. In S109, it is determined whether or not the processing of all areas of the image data has been completed. If the processing of all the areas has not been completed, the process returns to S101 and the unprocessed line is processed. When the process for all the regions is completed, the preliminary ejection data adding process is terminated.

  FIG. 26 is a diagram illustrating a result of performing the process of adding preliminary ejection data while avoiding the digital watermark embedding area in the fourth embodiment.

  An area 81 is a digital watermark embedding area. The dot position 82 is a position from which the dot moved to another location is moved. The dot position 83 is a position to which the moved dot is moved. Preliminary ejection is performed in the preliminary ejection permitted area of image data, and preliminary ejection is not performed in the digital watermark embedding area.

  As a result of performing the above processing, it is possible to control so that the digital watermark embedding area and the preliminary ejection portion do not overlap.

  In the fourth embodiment, when the pixel counter C value is within the digital watermark embedding area when reaching the ejection cycle, the preliminary ejection is not performed, and the preliminary ejection is performed when the preliminary ejection permission area is reached after the processing is continued.

  If the count value of the pixel counter C is predicted to reach the ejection cycle in the digital watermark embedding area, the preliminary ejection may be controlled before reaching the digital watermark embedding area.

  The above-described embodiment may be applied by a printer driver of the host PC 190.

  That is, the above embodiment is an ink jet type image forming apparatus in which an image is formed on a recording medium by ejecting ink from the recording element. Further, in the above-described embodiment, in order to keep the ejection performance of the recording element good, preliminary ejection data for preliminarily ejecting ink from the recording element to the recording medium is added to the print image data. It has discharge data adding means. Further, the above embodiment has a digital watermark embedding means for embedding a digital watermark. In addition, the above-described embodiment has the overlapping process preventing means for preventing the preliminary ejection permission area and the digital watermark embedding area from being processed in an overlapping manner. The preliminary ejection permission area is an area where the preliminary ejection data adding means is permitted to add the preliminary ejection data to the recording medium, and the digital watermark embedding area is an electronic watermark embedding means. This is an area for executing processing for embedding a watermark.

  In this case, the duplication processing preventing means is an area dividing means for dividing the preliminary ejection permission area and the digital watermark embedding area prior to the processes of the preliminary ejection data adding means and the digital watermark embedding means.

  The area dividing means is a means for distributing and arranging the preliminary ejection permission area and the digital watermark embedding area.

  Further, the overlap processing prevention means is preliminary discharge area avoiding means for arranging the digital watermark embedding area by avoiding the preliminary discharge permission area after the preliminary discharge data is added by performing the processing by the preliminary discharge data adding means. is there.

  In addition, the duplication processing prevention means is preliminary ejection area prediction means for performing control so that the digital watermark embedding area is not arranged in an area where paper preliminary ejection is predicted to be performed.

  The preliminary ejection region predicting means is an means for predicting that preliminary ejection is performed when the predetermined number of pixels is continuous as the value of the print image data in the data that does not eject ink. Forming equipment.

  In addition, the duplication processing preventing means is a digital watermark embedding area avoiding means for performing the processing by the digital watermark embedding means and arranging the inside of the preliminary ejection permission area while avoiding the electronic watermark embedding area.

  The digital watermark embedding area avoiding means is a means for arranging the digital watermark embedding areas in a distributed manner.

  Further, the electronic watermark embedding area avoiding means moves the pre-ejection data to the pre-ejection permission area when the arrangement position of the pre-ejection data added by the preliminary ejection data adding means exists in the digital watermark embedding area. It is means to arrange.

  In addition, the digital watermark embedding area avoiding means may perform preliminary ejection when the preliminary ejection data added by the preliminary ejection data adding means is located in the digital watermark embedding area and reaches the preliminary ejection permitted area. It is a means to perform.

  The electronic watermark embedding area avoiding means predicts that the location of the preliminary ejection data added by the preliminary ejection data adding means is present in the electronic watermark embedding area, and then reserves the preliminary watermark data before reaching the electronic watermark embedding area. It is means for performing discharge.

Moreover, the said Example can be grasped | ascertained as invention of a method. That is, the above embodiment is a control method of an ink jet type image forming apparatus in which an image is formed on a recording medium by ejecting ink by the recording element. In the above embodiment, in order to keep the ejection performance of the recording element good, preliminary ejection data for preliminarily ejecting ink from the recording element to the recording medium is added to the print image data, A preliminary ejection data adding step for storing in the storage device; In addition, the above embodiment has a digital watermark embedding step of embedding a digital watermark and storing it in a storage device. The above-described embodiment includes an overlapping process preventing step for preventing the preliminary ejection permission area and the digital watermark embedding area from being processed in an overlapping manner.

1 is a block diagram illustrating an image forming apparatus PR1 that is Embodiment 1 of the present invention. FIG. It is a figure explaining the image forming method in image forming apparatus PR1. 6 is a diagram illustrating a printing process in image formation in Embodiment 1. FIG. 6 is a diagram illustrating dot arrangement when preliminary ejection is performed on paper P in Embodiment 1. FIG. FIG. 6 is a diagram illustrating that the embodiment in which the area where the electronic watermark is embedded and the preliminary ejection portion do not overlap in the first embodiment. 6 is a flowchart for performing a digital watermark embedding process and a preliminary ejection process in the first embodiment. In Example 1, it is a figure which shows the example of the operation | movement which an area | region division means divides | segments an area | region. 6 is a flowchart illustrating an operation of digital watermark embedding processing by the digital watermark embedding unit in the first embodiment. 6 is a flowchart illustrating an operation of adding preliminary ejection data in the first embodiment. It is a figure which shows the process result in Example 1. FIG. 10 is a flowchart illustrating a digital watermark embedding process and a preliminary ejection process in a modification of the first embodiment. 6 is a flowchart illustrating a specific processing procedure in a modification of the first embodiment. 9 is a flowchart for performing digital watermark embedding processing and preliminary ejection processing in the second embodiment. In Example 2, it is explanatory drawing of the operation | movement which a preliminary | backup ejection area | region avoiding means designates an area | region. 9 is a flowchart illustrating a digital watermark embedding process procedure by a digital watermark embedding unit in the second embodiment. 10 is a flowchart for performing digital watermark embedding processing and preliminary ejection processing in the third embodiment. In Example 3, it is a figure explaining the prediction operation | movement by the preliminary discharge area | region prediction means. 10 is a flowchart in which a digital watermark embedding unit performs a digital watermark embedding process in the third embodiment. In Example 3, it is a figure which shows the result of having performed the process which estimates the location which performs preliminary discharge and embeds a digital watermark. 14 is a flowchart illustrating an operation of performing digital watermark embedding processing and preliminary ejection processing in Embodiment 4 of the present invention. In Example 4, it is a figure explaining the digital watermark data embedding method. In Embodiment 4, it is a figure explaining the normal preliminary discharge data addition method. In Example 4, it is a figure explaining the normal preliminary discharge data addition method for every line. FIG. 10 is a diagram illustrating an operation of adding preliminary ejection data while avoiding a digital watermark embedding area in the fourth embodiment. 10 is a flowchart showing processing of preliminary ejection data adding means in the fourth embodiment. In Example 4, it is a figure which shows the result of having performed the process which avoids a digital watermark embedding area and adds preliminary discharge data.

Explanation of symbols

PR1 ... image forming apparatus,
10 ... Controller part,
11 ... CPU,
12 ... Interface control unit,
13 ... ROM,
14 ... RAM,
15… EEPROM,
16 ... operation panel control unit,
17. Image processing unit,
18 ... Head control unit,
19 ... Carriage motor controller,
20 ... paper transport motor controller,
31 ... Operation panel section,
32. Head part,
33 ... Carriage motor section,
34 ... paper transport motor section,
190 ... Host PC,
P ... paper,
40. Carriage part,
41 ... carriage motor shaft,
42 ... carriage motor bearing,
43. Timing belt,
44. Timing belt rotating shaft,
45. Timing belt fixed shaft,
51 ... paper transport motor shaft,
52 ... Paper transport motor bearing,
53. Paper transport roller,
P1 ... origin P2 to P4 ... dot position,
61-64 ... area,
71, 72 ... preliminary ejection data,
73 ... dot position,
81 ... dot position,
82: The original dot position,
83: Destination dot position.

Claims (12)

In an inkjet image forming apparatus in which an image is formed on a recording medium by ejecting ink by a recording element.
Preliminary discharge data adding means for adding, to the print image data, preliminary discharge data for preliminarily discharging ink from the recording element to the recording medium in order to keep the discharge performance of the recording element good;
An electronic watermark embedding means for embedding an electronic watermark;
A preliminary ejection permission area, which is an area where the preliminary ejection data adding means is permitted to add preliminary ejection data to the recording medium, and an electronic area, where the digital watermark embedding means executes a process of embedding a digital watermark. Duplication processing prevention means for preventing the watermark embedding area from being processed in an overlapping manner;
An image forming apparatus comprising: In claim 1,
The duplicate processing prevention means is:
An image forming apparatus, comprising: an area dividing unit that divides the preliminary ejection permission area and the digital watermark embedding area prior to processing of the preliminary ejection data adding unit and the digital watermark embedding unit. In claim 2,
The region dividing means is
An image forming apparatus, wherein the preliminary ejection permission area and the digital watermark embedding area are arranged in a distributed manner. In claim 1,
The duplicate processing prevention means is:
An image forming apparatus, comprising: a preliminary ejection area avoiding means for arranging a digital watermark embedding area by avoiding the preliminary ejection permitted area after the preliminary ejection data is added by performing the processing by the preliminary ejection data adding means. . In claim 1,
The duplicate processing prevention means is:
An image forming apparatus, comprising: a preliminary ejection area predicting unit that performs control so that the digital watermark embedding area is not disposed in an area where preliminary ejection on paper is predicted to be performed. In claim 5,
The preliminary ejection area prediction means includes
An image forming apparatus comprising: a unit that predicts that preliminary ejection is performed when a predetermined number of pixels continue as data for not ejecting ink as a value of print image data. In claim 1,
The duplicate processing prevention means is:
An image forming apparatus, comprising: a digital watermark embedding area avoiding unit that arranges a preliminary ejection permission area while avoiding an electronic watermark embedding area after processing by the digital watermark embedding means. In claim 7,
The digital watermark embedding area avoiding means is:
An image forming apparatus, characterized in that the electronic watermark embedding area is a means for arranging the areas in a distributed manner. In claim 8,
The digital watermark embedding area avoiding means is:
The preliminary ejection data added by the preliminary ejection data adding means is a means for moving and arranging preliminary ejection data to the preliminary ejection permission area when the location of the preliminary ejection data added exists in the digital watermark embedding area. Image forming apparatus. In claim 9,
The digital watermark embedding area avoiding means is:
An image characterized in that when the preliminary ejection data added by the preliminary ejection data adding means is located in the digital watermark embedding area, the preliminary ejection data is a means for performing preliminary ejection when the preliminary ejection permission area is reached. Forming equipment. In claim 9,
The digital watermark embedding area avoiding means is:
When the preliminary ejection data added by the preliminary ejection data adding means is predicted to be located in the digital watermark embedding area, the preliminary ejection data adding means is a means for performing preliminary ejection before reaching the digital watermark embedding area. Image forming apparatus. In a control method of an image forming apparatus of an ink jet system in which an image is formed on a recording medium by ejecting ink by a recording element,
Preliminary ejection for preliminarily ejecting ink from the recording element to the recording medium and preliminarily ejecting ink from the recording element to the print image data and storing it in a storage device in order to maintain good ejection performance of the recording element A data addition step;
A digital watermark embedding step of embedding the digital watermark and storing it in a storage device;
A preliminary ejection permission area, which is an area where the process of adding preliminary ejection data to the recording medium in the preliminary ejection data adding process is permitted, and an electronic area, in which the digital watermark embedding process executes a process of embedding a digital watermark A duplication processing preventing step for preventing the watermark embedding area from being processed in an overlapping manner;
A control method for an image forming apparatus, comprising:

Images