JP4760221B2 - Image forming apparatus and dod size setting method of image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus and a dod size setting method for an image forming apparatus.

Conventionally, a dot pattern (tracking information) composed of a plurality of dots has been embedded in an image in order to suppress counterfeiting of securities such as banknotes. As described above, embedding a dot pattern composed of a plurality of dots is effective for specifying an image forming apparatus. However, on the other hand, there is a concern that the image quality may deteriorate after the dot pattern is added. In view of this, a proposal has been made to prevent the deterioration of image quality by suppressing the color unevenness of the dots by making the number of dots constituting the dot pattern constant (for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-112787

However, limiting the number of dots to a constant means that the amount of tracking information added to the image is limited, and there is room for improvement in this regard.
The present invention has been completed based on the above circumstances, and has a high color reproducibility (the same when an identical image is formed) with a wide range of the number of dots constituting the tracking information. It is an object of the present invention to provide an image forming apparatus that can ensure printing with such a hue, and a method for manufacturing the image forming apparatus.

  As a means for achieving the above object, the invention according to claim 1 is directed to an image forming apparatus that outputs a specific pattern composed of a plurality of dots added to a plurality of positions in an image forming area. The specific patterns are configured such that the specific patterns having different numbers of dots constituting the specific patterns are used, and the area ratio of the dots in the specific patterns is close to each other between the specific patterns having different numbers of dots. It has a feature in that an adjusting means for changing the size of the dot according to the number of dots used is provided.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the minimum dot constituting the specific pattern is set larger than the minimum dot that can be read by a reading device that reads the specific pattern.

  The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the size of the area occupied by the specific pattern is constant regardless of the number of dots used in the specific pattern. Have.

  The invention of claim 4 is characterized in that the same specific pattern is repeatedly given to a plurality of positions in the region where the image can be formed in any one of claims 1 to 3.

  According to a fifth aspect of the present invention, in the apparatus according to any one of the first to fourth aspects, the adjusting means is configured so that the adjusted area ratio is smaller than an area ratio that is a predetermined reference. It is characterized by changing the size of the dots.

  A sixth aspect of the invention is characterized in that, in any of the first to fifth aspects, the dot size is changed by adjusting the dot size in the main scanning direction.

  A seventh aspect of the invention is characterized in that the specific pattern is constituted by dots of the same size in any one of the first to sixth aspects.

The invention of claim 8, a particular pattern consisting of several dots double, in addition to a plurality of positions of the image forming area A dot size setting process of images forming apparatus that to form an image, a specific pattern in where the area ratio occupied by the dots, so as to approach each other between specific pattern number of dots are different from each other, which was previously determined size of dots in accordance with the number of used dots forming the specific pattern is stored in memory in It has the characteristics.

<Invention of Claims 1 and 8>
According to the first and eighth aspects of the invention, since the size of the dots is adjusted so that the area ratios of the specific patterns are close to each other, the same image is printed even if the number of used dots is different. In this case, it is possible to perform printing with the same hue and to secure high color reproducibility.

<Invention of Claim 2>
If the dots that make up the specific pattern are determined without considering the performance of the reading device, the minimum dot may be smaller than the size that can be read in some cases, which may interfere with the reading of the specific pattern. According to the configuration of the second aspect, since each dot constituting the specific pattern is set to be larger than the minimum one that can be read by the reading device, it is possible to avoid such trouble beforehand.

<Invention of Claim 3>
In order to keep the area ratio constant, for example, it may be possible to change the size of the area according to the number of dots used. In this case, if the area is made too wide, a specific pattern is printed on the image part (actually printed). There is a risk that the reading of a specific pattern may be hindered. In this regard, according to the invention of claim 3, since the area is kept constant and is not expanded, the probability that the specific pattern overlaps the image portion can be lowered, thereby avoiding the trouble beforehand. It becomes possible.

<Invention of Claim 4>
If the specific pattern overlaps the colored part of the image, the specific pattern cannot be read, so it is desirable to repeatedly apply the specific pattern within the area where the image can be formed. If the configuration is given, the processing is time-consuming and the printing speed may be reduced. In this regard, according to the invention of claim 4, the same specific pattern is repeatedly given to a plurality of positions. With such a configuration, the process of applying the specific pattern can be performed quickly, and the printing speed does not decrease.

<Invention of Claim 5>
According to the invention of claim 5, the dots constituting the specific pattern are changed so that the adjusted area ratio becomes smaller than the reference area ratio. In this way, since the dot area ratio is always adjusted to be lower than the reference, the specific pattern can be made thinner (becomes thinner as a whole) and made inconspicuous.

<Invention of Claim 6>
According to the sixth aspect of the present invention, the size of the dots can be easily changed simply by adjusting the laser irradiation time.

<Invention of Claim 7>
According to the seventh aspect of the present invention, since the specific pattern is configured by dots of the same size, the process of providing the specific pattern can be performed more rapidly.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
1. Overall Configuration FIG. 1 is a side sectional view of a main part of a laser printer. In the following description, for the front and rear directions, the front direction of the apparatus will be described as the front side (the right side in FIG. 1).
A laser printer (corresponding to the image forming apparatus of the present invention) 1 is configured as a four-cycle color laser printer, and includes a sheet feeding unit 7 that accommodates sheets 5 as recording media in a stacked manner on the bottom side of a main body casing 3. Above that, a paper transport path Y is formed.

  The sheet conveyance path Y is as shown by a solid line in FIG. 1, and is reversed at about 180 degrees to the rear of the laser printer 1 at the upper front portion of the paper feeding unit 7 and then toward the rear portion of the laser printer 1. Then, when reaching the rear end side, this time, it is reversed forward by about 180 degrees to take a path to the paper discharge tray 69 provided on the upper surface wall of the main casing 3. As will be described in detail below, a toner image in the process of being conveyed through the sheet conveyance path Y is formed on the sheet fed from the sheet feeding unit 7, and this is thermally fixed by the fixing unit 29 so as to be desired. Images are formed.

2. Configuration of Each Unit The sheet feeding unit 7 includes a sheet feeding tray 11, a sheet feeding roller 13, a conveying roller 15, and a registration roller 17. The paper feed roller 13 takes out the paper 5 one by one, and the transport roller 15 transports the fed paper 5 to an image forming position (a contact position with a transfer roller 27 described later).

  The image forming unit 9 includes a scanner unit 21, a process unit 23, and an intermediate transfer belt mechanism unit 25. The scanner unit 21 includes a laser light emitting unit (not shown), a polygon mirror, a plurality of lenses, and a reflecting mirror. In the scanner unit 21, a belt photoconductor (OPC: Organic Photo Conductor) that moves along the sub-scanning direction by passing or reflecting the laser light emitted from the laser light emitting section through a polygon mirror, a reflecting mirror, and a lens. ) Irradiate the surface of 33 by high-speed scanning along the main scanning direction.

  The process unit 23 includes a belt photoreceptor mechanism unit 31 and a developing cartridge 35. The belt photosensitive member mechanism 31 includes a first belt photosensitive roller 39, a second belt photosensitive roller 41, a third belt photosensitive roller 43, and belt photosensitive members wound around the three photosensitive rollers 39, 41, and 43. The belt photoconductor charger 45, the potential adder 47, and the potential gradient controller 49 are additionally provided.

  The surface of the belt photoconductor 33 is uniformly positively charged by the belt photoconductor charger 45 and then exposed by high-speed scanning of laser light from the scanner unit 21. Since the charged portion is eliminated in the exposed portion, an electrostatic latent image is formed on the surface of the belt photosensitive member 33 in which a positively charged portion and an uncharged portion are arranged.

  The developing cartridge 35 includes a developing roller 37, a separation solenoid 38, a supply roller (not shown), a toner storage unit, and the like, and is dedicated to each color, that is, a yellow developing cartridge 35Y that stores yellow toner, and cyan toner. Are provided, a cyan developing cartridge 35C containing magenta toner, a magenta developing cartridge 35M containing magenta toner, and a black developing cartridge 35K containing black toner.

  These developing cartridges 35K, 35C, 35M, and 35Y are arranged in the vertical direction with the developing roller 37 facing the belt photosensitive member 33, and drive the separation solenoids 38K, 38C, 38M, and 38Y. As a result, the developing rollers 37K, 37C, 35M, and 35Y can be brought into contact with the surface of the belt photosensitive member 33 individually.

  Then, for example, when the developing roller 37Y of the yellow developing cartridge 35Y is brought into contact with the belt photoreceptor 33 on which the electrostatic latent image is formed (the other developing rollers are separated), the positively charged yellow toner Adheres only to the uncharged portion of the belt photoreceptor 33. As a result, a yellow visible image is formed on the belt photoreceptor 33.

  The intermediate transfer belt 51 constituting the intermediate transfer belt mechanism unit 25 is for sequentially transferring visible images of respective colors formed on the belt photoreceptor 33 to form a color image (toner image). The first intermediate transfer belt roller 53, the second intermediate transfer belt roller 55, and the third intermediate transfer belt roller 57 are supported by three rollers. An intermediate transfer belt roller 53 is disposed opposite to the intermediate transfer belt roller 53. Therefore, in the previous example, when the belt photoconductor 33 moves, the yellow visible image is transferred to the surface of the intermediate transfer belt 51 when facing the intermediate transfer belt 51.

  In order to form a color image on the intermediate transfer belt 51, it is necessary to transfer other colors other than yellow. For this purpose, the same transfer procedure as that for yellow may be repeated. That is, if the image is a magenta visible image, the magenta separation solenoid 38M is driven to contact only the developing roller 37M of the magenta developing cartridge 35M with the belt photosensitive member 33.

  As a result, a magenta visible image is formed on the belt photoreceptor 33. The magenta visible image has already been transferred to the yellow visible image when the belt photosensitive member 33 moves and the magenta visible image faces the intermediate transfer belt 51 in the same manner as described above. Then, the image is transferred onto the intermediate transfer belt 51 in an overlapping manner. Such a similar operation is repeated with cyan toner accommodated in the cyan developing cartridge 35C and black toner accommodated in the black developing cartridge 35K, whereby a color image is formed on the intermediate transfer belt 51. .

  The transfer roller 27 is for collectively transferring the color image formed on the intermediate transfer belt 51 onto the paper 5, and is formed by coating a roller made of a conductive rubber material on a metal roller shaft. . The transfer roller 27 is disposed opposite to the third intermediate transfer belt roller 57 with the intermediate transfer belt 51 interposed therebetween. Therefore, the color image formed on the intermediate transfer belt 51 is transferred onto the paper 5 by the transfer roller 27 while the paper 5 passes between the intermediate transfer belt 51 and the transfer roller 27.

  The fixing unit 29 is disposed behind the intermediate transfer belt mechanism unit 25, and includes a heating roller 61, a pressing roller 63 that presses the heating roller 61, and a pair of downstream rollers of the heating roller 61 and the pressing roller 63. A conveyance roller 65. The heating roller 61 includes a halogen lamp for heating, with an outer layer made of silicon rubber and an inner layer made of metal. The heating roller 61 heat-fixes the color images collectively transferred onto the paper 5 by the transfer roller 27 while the paper 5 passes between the heating roller 61 and the pressing roller 63.

3. Electrical Configuration Next, the electrical configuration of the laser printer 1 will be described. FIG. 2 is a block diagram conceptually showing the electrical configuration of the laser printer 1. As shown in FIG. 2, the control device 90 includes a CPU 91, ROM 92, RAM 93, image memory 94, control unit 97, additional information memory 110, and additional pattern generation unit (corresponding to the adjusting means of the present invention) 100. Reference numeral 95 denotes an interface (IF) for connecting to an external device such as a personal computer (PC) 150.

  The ROM 92 stores various control programs for controlling the printer 1, and the RAM 93 is used as a work area from which various control programs are read. The image memory 94 temporarily stores image data obtained by developing a print job received through the interface 95.

  The additional information memory 110 stores additional information such as the manufacturer name of the laser printer 1, the printer model name, the transmission date and time of the print job sent along with the print job, and the user name. The additional pattern generation unit 100 generates an additional pattern (corresponding to the specific pattern of the present invention) as tracking information based on the additional information stored in the additional information memory 110.

  The control unit 97 is composed of an ASIC (Application Specific Integrated Circuit), and is electrically connected to the image forming unit 9 described above, the operation unit 98 including an input panel, and the display unit 99 including various lamps. The CPU 91 controls each of these units, that is, the control unit 97, the image memory 94, the additional information memory 110, and the additional pattern generation unit 100 according to a flowchart described below to form a color image on the paper 5. is there.

FIG. 3 is a flowchart showing the flow of print processing executed by the CPU 91.
When the power of the laser printer 1 is turned on by the operator, first, initialization processing (for example, processing for initializing the RAM 93, the image memory 94, and the additional information memory 110) is performed by the CPU 91, and then from the host device. The process waits for a print job to be transmitted (step 10). Then, when a print job is transmitted from the personal computer 150 as the host device, this is received by the control device 90 through the interface 95 (step 20).

Then, the process proceeds to step 30 following the reception of the print job. In step 30, the CPU 91 performs processing for expanding the received print job (PDL data) into image data (raster data), and then processing for storing the generated image data in the image memory 94 is performed.
Note that the data transmitted from the personal computer 150 includes additional information such as a print job transmission date and time and a user name in addition to the print job, and the CPU 91 stores the additional information in the additional information memory 110. The processing to be performed is also performed.

Following the processing in step 30, this time, the routine proceeds to step 40. In step 40, a process for generating an additional pattern to be superimposed on the image data is performed.
The additional pattern is a dot pattern generated based on the additional information stored in the additional information memory 110, and represents the manufacturer name, printer model name, print job transmission date and time, and user name by the dot arrangement. .

  As will be described in detail later, the additional pattern generation unit 100 has an adjustment function for adjusting the size of each dot. When generating a dot pattern (additional pattern), the additional pattern generation unit 100 generates a dot pattern. A process of adjusting the dot size according to the number of uses is performed. As a result, the color reproducibility is reduced by embedding the additional pattern in the image, that is, the color of the formed image is changed due to the difference in the number of dots of the additional pattern embedded in the image despite the formation of the same image. The problem of being different is avoided.

  Thereafter, the process proceeds to step 50. In step 50, the image data is sequentially read from the image memory 94, and a process of superimposing an additional pattern on the read image data is performed by the CPU 91. The image data on which the additional pattern is superimposed is output to the control unit 97, and the control unit 97 controls the image forming unit 9 and each device in accordance with this.

  Accordingly, a series of image forming processes is started by driving a motor (not shown) as a drive source. That is, the conveyance of the paper 5 is started and laser light is irradiated at a predetermined timing, whereby an electrostatic latent image is formed on the surface of the belt photoreceptor 33 according to the image data on which the additional pattern is superimposed. Is done. Thereafter, a visible image obtained by developing the electrostatic latent image through the developing roller 37 is formed on the belt photoreceptor 33, and this is transferred to the intermediate transfer belt 51.

  By sequentially repeating this for each toner color, a color image including an additional pattern is formed on the intermediate transfer belt 51. The formed color image is then transferred onto the paper 5 by the transfer roller 27 when the paper 5 passes the image forming position. Thereafter, the color image is thermally fixed by passing through the fixing unit 29, and the sheet 5 is discharged onto a discharge tray 69 formed on the upper portion of the main body casing 3 by a discharge roller 67.

4). Specific Configuration and Generation Procedure of Additional Pattern FIG. 4 is a diagram illustrating an example of the additional pattern. The additional pattern is obtained by attaching a plurality of dots to a crossing portion of the lattice shown in FIG. 4 in a predetermined arrangement corresponding to the additional information. In the present embodiment, a basic block (a grid indicated by a thick line in FIG. 4) having a 4 × 4 intersection is used as one unit, and four such basic lattices are collected to form one block B. ing.

  In addition, the size of the basic grid, that is, the width between the grids, the narrower the interval between the arranged dots, and the dot traces become noticeable after image formation. In order to avoid this, it is sufficient to increase the width between the lattices. In this case, however, there is a high probability that the additional pattern overlaps the image portion (the portion colored by the toner), which may cause a reading failure. (Readability). From the above, the lattice width of the basic lattice is fixedly set in advance so as to ensure readability and not to deteriorate the color.

  The area surrounded by the basic grid corresponds to the “area occupied by the specific pattern” in the present invention, and the grid width of the basic grid is fixedly determined, so The size of the area occupied by the pattern is constant regardless of the number of dots used in the specific pattern ”.

  Each basic grid has different additional information, specifically, the manufacturer name for the basic grid A1, the printer model name for the basic grid A2, the transmission date and time of the print job for the basic grid A3, the basic User names are assigned to the grid A4.

  Among the additional information, the manufacturer name and printer model name are information that is unique to the apparatus, that is, the same laser printer 1 does not change.

  On the other hand, among the additional information, the transmission date and time of the print job and the user name are data transmitted from the personal computer 150, and the information contents are different each time. Therefore, for these additional information, it is necessary to change the dot arrangement according to the information content.

  The additional pattern generation unit 100 stores conversion data and adjustment data in advance. The conversion data replaces the additional information with a dot pattern. For example, when the transmission date and time of a certain print job is input, the number of dots and the arrangement of each dot in the basic grid are determined accordingly. Here, although it is the number of dots constituting the additional pattern, in this embodiment, the number of dots used is set to 4-8. In this way, by giving a certain range to the number of dots used, it becomes possible to give variations to the arrangement of dots, so that the amount of information of the additional information as a whole can be increased accordingly.

  On the other hand, as described above, the size of the basic lattice is constant. Therefore, as described above, if the number of dots used is wide, the total area of the dots changes depending on whether the number of dots used is large or small, so that the area ratio of the dots in the basic lattice is different. As a result, the color reproducibility is degraded.

Therefore, the dots of different sizes are set in advance, and when the number of dots is small, a larger dot is used, and when the number of dots is large, a smaller dot is used. The dot size is selected in accordance with the number of dots used, and the adjustment data is a collection of the use patterns (combinations of dot sizes) as data.
The area ratio occupied by dots in the basic lattice corresponds to the “area ratio occupied by dots in the specific pattern” of the present invention.

  FIG. 5 is a diagram illustrating an example of adjustment data. The dot No. in the figure represents the size of the dot, and the smaller the number, the smaller the dot. In this embodiment, eight types of dots No. 1 to No. 8 are set (the dot shape will be described later). Yes.

  According to the same data, for example, when the additional pattern is composed of 5 dots, the combination of 4 No. 5 dots and 1 No. 6 dot is used, and the additional pattern consists of 6 dots. When configured, the combination is 5 No3 dots and 1 No4 dot.

  In the lower column of the figure, the ratio of the total area of each combination (the total area of dots when the additional pattern is composed of four dots is used as a reference (100%)) is shown. Is also in the range of ± 1%. Thus, by using a combination of dots of different sizes, the total area can be set to be approximately equal regardless of the number of dots used.

Next, the shape of each dot (No1 to No8 dot) will be described.
Since the additional pattern must be readable after printing, each dot needs to be set larger than the smallest dot (hereinafter referred to as a reference dot) that can be read by the reading device (device that reads the printed dot). . Therefore, in the present embodiment, the shape and size of each dot are determined as follows based on the diameter L of the reference dot.

  FIG. 6 is a diagram showing the shape of the maximum dot. As shown in the figure, the maximum dot is an ellipse along the main scanning direction of the laser light (the direction perpendicular to the feeding direction of the paper 5 in the sub-scanning direction and the horizontal direction in the figure), specifically Is an ellipse having a diameter L and a distance L between centers.

  The distance between the centers (corresponding to the size of the dot in the main scanning direction of the present invention) L is divided into 8 and the total length of the dots is shortened stepwise to determine the remaining dots excluding the largest dot. . That is, if it is the smallest dot, it is an oval shape having a diameter of L and a distance between centers of L / 8, and if it is the second smallest dot after the smallest dot, the diameter is L and the distance between centers is 2L / 8. The shape is an ellipse, and the other shapes are determined in the same manner. FIG. 7 shows the shape of the fourth smallest dot.

  In this way, each dot is formed into an oval shape along the main scanning direction of the laser beam, and the size is changed by shortening the total length of the dots step by step. Therefore, with such a configuration, the dot size can be easily changed by simply adjusting the ON / OFF of the laser beam.

  The distance between the centers is equally divided into eight in response to a request from the drive circuit side that controls the lighting of the laser light. That is, the laser light cannot be turned off unless the drive circuit is synchronized with the operation clock.

Next, a specific additional pattern generation procedure will be described.
FIG. 8 is a flowchart showing an additional pattern generation procedure executed by the additional pattern generation unit 100. When the additional pattern generation unit 100 reaches the additional pattern generation stage (previous step 40), it reads out additional information from the additional information memory 110, that is, the manufacturer name, printer model name, print job transmission date and time, and user name. (Step 41).

  After reading the additional information, the process proceeds to step 43 to perform processing for converting the additional information into a dot pattern. That is, the additional pattern generation unit 100 determines the number of dots to be added to the basic grid and the arrangement of each dot based on the conversion data and the read additional information.

  When the generation of the dot pattern is completed, the process proceeds to step 45, where the additional pattern generation unit 100 performs a process of detecting the number of dots used. Here, it is assumed that five dots are detected from the dot pattern related to the transmission date and time of the print job, and eight dots are detected from the dot pattern related to the user name.

When the detection of the number of used dots is completed, the process proceeds to step 47, where the additional pattern generation unit 100 performs processing for determining the dot size by comparing the detected number of used dots with the adjustment data. That is, if the dot pattern is related to the transmission date and time of the print job, the number of dots used is 5, so that the combination of four No5 dots and one No6 dot is a dot pattern related to the user name. Since the number of dots used is eight, the number of No1 dots is a combination of eight.
In the above description, the generation process of the additional pattern has been described by taking the transmission date and time of the print job and the user name as examples. However, the same processing is performed for the manufacturer name and printer model name, that is, the number of used dots is detected. In addition, subsequent processing for determining the dot size is performed to determine the additional pattern.

Thus, the generation of the additional pattern related to the manufacturer name, printer model name, print job transmission date and time, and user name is completed.
In addition, by the processing of step 45 and step 47 executed in the additional pattern generation unit 100, “dots constituting a specific pattern so that the area ratio of dots in the specific pattern approaches each other between the specific patterns” of the present invention. "Change the size of the dot according to the number of used" is realized.

  When the additional pattern is generated in the above manner, the process proceeds to step 49, and processing for assigning each additional pattern to each basic lattice is performed. In other words, the additional pattern generation unit 100 assigns the additional patterns relating to the manufacturer name, printer model name, print job transmission date and time, and user name generated in the processing in step 47 to the basic grid A1 to the basic grid A4. To do.

  Thereafter, the process proceeds to step 50 described above, and the CPU 91 performs a process of superimposing the additional pattern on the image data. More specifically, the CPU 91 generates data in which one block B composed of four basic lattices A1 to A4 is allocated over almost the entire image forming area of the paper, and superimposes the data on the image data. . Then, the image data on which the additional pattern is superimposed is output to the control unit 97, and as shown in FIG. 9, the same additional pattern (in the figure, blocks are shown) at a plurality of positions on the paper 5. Will be printed repeatedly.

  As described above, according to the present embodiment, the number of dots used to form the additional pattern has a width (4 to 8). Therefore, since it is possible to give variations to the arrangement of dots, it is possible to give more variations to additional information.

  On the other hand, when the number of dots used is small, a larger dot is used, and when the number of dots used is large, a smaller dot is used. The dot size is selected according to the size. Therefore, the area ratio of dots occupying the basic grid can be kept almost constant regardless of the number of dots used. With such a configuration, even when different additional patterns are added, when the same image is printed, it is possible to perform printing with the same hue (color), and high color reproducibility. It can be secured. In other words, in spite of forming the same image, it is possible to avoid the problem that the color of the formed image is different due to the difference in the number of dots of the additional pattern embedded in the image.

  In addition, if the dots constituting the additional pattern are determined without considering the performance of the reading device, the minimum dot may be smaller than the readable size in some cases, which may hinder the reading of the pattern. In this embodiment, since each dot (No1 to No8) is set to be larger than the minimum dot that can be read by the reading device, it is possible to avoid such trouble beforehand.

  Further, since the additional pattern cannot be read at the portion where the image portion (colored portion) and the additional pattern overlap, in order to read the additional pattern after printing, the paper should be attached to the margin portion of the paper. It is preferable to repeatedly print additional patterns at a plurality of positions 5. On the other hand, if repeated printing is performed in this way, the processing takes time and the printing speed may decrease. However, in the present embodiment, the same additional pattern is repeatedly printed. Can be minimized.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.
The second embodiment is different from the first embodiment in that one dot type (No zero) is added to nine types, and the content of the adjustment data is changed. The newly added dot is smaller than the smallest dot in the first embodiment, and the shape thereof is a circular shape having a diameter L as in the case of the reference dot.

  FIG. 10 is a diagram illustrating adjustment data according to the second embodiment. In the adjustment data of the second embodiment, the combination of the case where the number of dots is 5 and the case where the number of dots is 8 is changed so that the total area becomes smaller than the adjustment data of the first embodiment. Yes. Specifically, when the number of dots used is 5, the combination of using No. 5 is used, and when the number of dots used is 8, the number of No No. is 7 and No. 6 It is a combination that uses one thing.

  In the first embodiment, the total area ratio in the case where the number of dots used is 5 and the number of dots used is 8 both exceeds 100%, but the combination is changed to the above combination. Thus, the total area ratio is less than 100% in all the usage numbers including the usage number of 5 and the usage number of 8.

In this way, if dots are combined so that the adjusted total area ratio is smaller than the reference total area ratio (in this case, the number of dots is 4 as a reference), The additional pattern is thin as a whole and can be made inconspicuous.
By using the adjustment data (dot combination) as described above, the “adjustment means of the present invention can reduce the area ratio after adjustment so that the area ratio after adjustment is smaller than the area ratio that is a predetermined reference. "Change the size of" is realized.

  In addition, when one additional pattern is configured by combining dots of different sizes, it is desirable to determine the dot arrangement procedure in advance. FIG. 11 and FIG. 12 exemplify such an example. FIG. 11 is a diagram showing the priority order in the sub-scanning direction, and FIG. 12 is a diagram showing the priority order of dots.

  In this example, in the sub-scanning direction, the priority is higher in order from the top, and the dot size is higher as the dot is larger, so as shown in FIG. The largest dot is first arranged in the upper part of the lattice. Since the remaining dots have the same size, the dots are arranged according to the priority order in the sub-scanning direction. In this way, if the dot placement procedure is determined in advance, the dots can be placed on the basic grid without confusion.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG.
In the third embodiment, the adjustment data is changed with respect to the first embodiment. The adjustment data of the third embodiment is as shown in FIG. 13. When the number of dots is 4, an additional pattern is configured with only No. 8 dots, and when the number of dots is 5, addition is performed with only No. 5 dots. When the pattern is configured and the number of dots is six, the additional pattern is configured only by No. 3 dots, and the additional pattern is configured by the same size dots for the remaining number of dots.
As described above, if each additional pattern is configured only with dots of the same size (corresponding to “the specific pattern is configured by dots of the same size” according to the present invention), printing can be performed. At this time, since the processing for changing the size of the dots is small, it contributes to speeding up the processing.

<Embodiment 4>
Next, Embodiment 4 of the present invention will be described.
In the first embodiment, the block B is composed of four basic grids, and additional information includes information unique to the apparatus (manufacturer name, printer model name), and information (information for a print job) that is different every time the information is printed. However, in the fourth embodiment, the configuration of the block B is changed to a configuration consisting of two basic grids, and additional information is obtained only from device-specific information (manufacturer name, printer model name). It becomes the composition which becomes.

  In accordance with the change of the additional information, in the present embodiment, in the manufacturing stage of the laser printer 1, a process for generating an additional pattern is performed in conjunction with the manufacture of the apparatus part constituting the printer, and this is stored in the additional information memory (of the present invention). (Corresponding to “memory”) 110. That is, the process for manufacturing the laser printer 1 is composed of a manufacturing process for manufacturing the image forming unit 9 and the like, and an adjustment process.

  In the adjustment process, the number of dots used to form a dot pattern (a dot pattern related to the manufacturer name and printer model name) is detected, and based on the number of detections and the adjustment data described in the first embodiment, the basic grid is used. The dot size is determined so that the area ratio of the occupied dots is substantially constant, and this is stored in the additional information memory 110 as an additional pattern unique to the apparatus.

  With such a configuration, it is not necessary to generate an additional pattern from the additional information at the printing stage, and when the additional pattern is added to the image, the additional pattern is read from the additional information memory 110, and this is read as image data. What is necessary is just to superimpose on. As described above, since the processing in the printing stage can be simplified, printing can be started early after the print job is transmitted. Further, as in the present embodiment, when the additional information is composed only of information unique to the apparatus, if the additional pattern is stored in the additional information memory 110 in advance, the laser printer 1 will be described in the first embodiment. There is no need to store the converted data and adjustment data.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.

  (1) In the first to third embodiments, adjustment data is stored in the laser printer 1 in advance, and the size of the dots is changed based on the adjustment data. However, the area ratio occupied by the dots approaches each other between the additional patterns. Thus, it is only necessary to have an adjustment function for changing the size of the dots.For example, the dot size is determined by calculation based on the number of dots used, and the size of the dots is adjusted based on this. May be.

  (2) In the first to third embodiments, three examples of the adjustment data are illustrated. However, the adjustment data is not limited to this, and various changes can be made. For example, three or more dots having different sizes are combined to form an additional pattern.

  (3) In the first to third embodiments, the block B is configured from the four basic lattices A1 to A4, and the four additional information is added to the image. In the fourth embodiment, the block B is composed of two basic lattices, and two additional information is added to the image. However, the configuration of the block B and the number of pieces of additional information are not limited to this, and various modifications, that is, the block configuration pattern can be further changed to increase or decrease the number of information to be added. .

FIG. 3 is a side sectional view of a main part of the laser printer according to the first embodiment. Block diagram conceptually showing the electrical configuration of the laser printer Flowchart diagram showing the flow of print processing The figure which shows an example of an additional pattern Diagram showing an example of adjustment data Diagram showing maximum dot shape Diagram showing the shape of the fourth dot The flowchart figure which shows the production | generation procedure of an additional pattern The figure which shows the state where the additional pattern is printed in plural positions on the paper The figure which shows the adjustment data in Embodiment 2. The figure which shows the priority order regarding the sub scanning direction Diagram showing the priority order of dot size The figure which shows the adjustment data in Embodiment 3.

1. Laser printer (image forming apparatus)
90 ... Control device 91 ... CPU
100: Additional pattern generation unit (adjustment means)
110 ... Additional information memory (memory)

Claims (8)

In an image forming apparatus for outputting a specific pattern composed of a plurality of dots added to a plurality of positions in an image forming area,
As the specific pattern, a specific pattern in which the number of used dots constituting the specific pattern is different from each other is used,
It is characterized by comprising adjusting means for changing the size of the dots according to the number of dots used in the specific pattern so that the area ratio of the dots in the specific pattern approaches each other between the specific patterns having different numbers of dots. An image forming apparatus. The image forming apparatus according to claim 1, wherein a minimum dot constituting the specific pattern is set larger than a minimum dot that can be read by a reading device that reads the specific pattern. The image forming apparatus according to claim 1, wherein the size of the area occupied by the specific pattern is constant regardless of the number of dots used in the specific pattern. The image forming apparatus according to claim 1, wherein the same specific pattern is repeatedly given to a plurality of positions in a region where the image can be formed. The size of the dot is changed so that the adjustment means has a smaller area ratio after adjustment than a predetermined area ratio as a reference. Image forming apparatus. 6. The image forming apparatus according to claim 1, wherein the size of the dots is changed by adjusting the size of the dots in the main scanning direction. The image forming apparatus according to claim 1, wherein the specific pattern is configured by dots of the same size. The specific pattern made of several dots double, in addition to a plurality of positions of the image forming area A dot size setting process of images forming apparatus that to form an image,
The area ratio occupied by the dots in the specific pattern, so as to approach each other between specific pattern number of dots are different from each other, predetermine the magnitude of the dot depending on the number of used dots forming the specific pattern, the memory A dot size setting method for an image forming apparatus , characterized by storing the dot size .

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