Printer and program

Abstract

To provide a technique to improve the image quality of characters when converting an image formed of multiple values into a two-gradation image before printing.SOLUTION: A printer 1 generates intermediate data that is a multi-valued image on the basis of image data to be printed, and converts the generated intermediate data into a two-gradation image through dither processing to generate a binarized image. The printer 1 performs printing based on the generated binarized image by using a printing device 15. Before generating the intermediate data, the printer 1 detects character data from the image data, when the size of characters indicated in the detected character data is equal to or more than a predetermined size, adds broken lines to edges of the characters indicated in the character data, and generates intermediate data on the basis of the characters added with the broken lines. When the size of the characters indicated in the character data is smaller than the predetermined size, the printer 1 does not add the broken lines.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technical field disclosed in this specification relates to a printer and a program capable of converting a multi-valued image into a two-tone image and printing it. [Background technology]

[0002] Conventionally, printers have been known to convert multi-level images into two-tone images using dithering or error diffusion processing, thereby expressing shades as a binary image. In this binary image, the lower the density, the greater the proportion of areas without dots. Therefore, when printing based on a binary image, areas where dots are significantly missing can be exposed at the edges, resulting in the occurrence of so-called jaggies. Therefore, a method for making edges appear smoother has been proposed, as disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 06-105130 Summary of the Invention [Problem to be solved by the invention]

[0004] When edge enhancement processing is applied to characters contained in a binary image to make the edges appear smoother, as in conventional technology, jagged edges are less likely to occur, but another problem arises: the characters may appear to have a border around them. [Means for solving the problem]

[0005] A printer that has been made to solve this problem is a printer that includes a printing device and a controller, wherein the controller is capable of executing an acquisition process that acquires image data, a multi-value image generation process that generates a multi-value image composed of multiple values ​​based on the image data acquired in the acquisition process, a binarization process that converts the multi-value image generated in the multi-value image generation process into two-tone images and generates a binarized image, and a print process that causes the printing device to perform printing based on the binarized image generated in the binarization process, and the controller further executes the acquisition process and then executes the multi-value image generation process. Before the acquisition process, a character detection process is executed to detect character data indicating characters from the image data acquired in the acquisition process, and if the size of the characters indicated in the character data detected in the character detection process is equal to or larger than a predetermined size, a dashed line addition process is executed to add dashed lines to edges of the characters indicated in the character data detected in the character detection process, and in the multi-value image generation process, the multi-value image is generated based on the characters to which the dashed lines have been added in the dashed line addition process, and if the size of the characters indicated in the character data detected in the character detection process is smaller than the predetermined size, the dashed line addition process is not executed.

[0006] The printer disclosed in this specification adds dashed lines to the edges of characters included in the image to be printed before generating a multi-valued image. This dashed line is expected to cover some of the large gaps exposed at the edges of the binarized characters. This makes the gaps at the edges of the characters less noticeable, suppressing the occurrence of jagged edges. However, when the characters are small in size, the gaps at the edges of the characters are less likely to occur, and adding dashed lines makes the lines more noticeable, which may result in a deterioration in quality. Since the printer does not add dashed lines to small characters, this deterioration in quality can be reduced.

[0007] A printing system including the printer, a control method for realizing the functions of the printer, a computer program, and a computer-readable storage medium storing the program are also novel and useful. [Effects of the Invention]

[0008] The technology disclosed in this specification realizes a technology that improves the image quality of characters when a multi-value image is converted into two-tone and printed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a printer. [Figure 2] 10 is a flowchart showing a procedure for print job processing. [Figure 3] 10 is a flowchart showing the procedure of a character intermediate data generation process. [Figure 4] FIG. 10 is an explanatory diagram showing an example of a text drawing command in PDF format. [Figure 5] 10 is a flowchart showing the procedure of a density adjustment process. [Figure 6] 10 is a flowchart showing the procedure for dashed line type determination processing. [Figure 7] FIG. 10 is an explanatory diagram showing an example of the relationship between character density and dashed line type. [Figure 8] FIG. 10 is an explanatory diagram showing an example of a portion of intermediate data to which a dashed line has been added. [Figure 9] FIG. 10 is an explanatory diagram showing an example in which the print resolution is low. [Figure 10] FIG. 10 is an explanatory diagram showing an example of a character with thin lines and low character density. [Figure 11] FIG. 10 is an explanatory diagram showing an example in which the character size is small. [Figure 12] FIG. 10 is an explanatory diagram showing an example of a portion of binarized data to which a dashed line has been added. [Figure 13] FIG. 2 is a block diagram showing a schematic configuration of a PC connected to a printer. [Figure 14] 10 is a flowchart showing a procedure for print job processing executed by a PC. DETAILED DESCRIPTION OF THE INVENTION

[0010] A printer according to an embodiment will be described in detail below with reference to the accompanying drawings. This embodiment discloses a printer capable of printing based on a multi-value color image.

[0011] As shown in Fig. 1, the printer 1 includes a controller 10 that includes a CPU 11 and a memory 12. The printer 1 also includes a user interface (hereinafter referred to as "user IF") 13, a communication interface (hereinafter referred to as "communication IF") 14, and a printing device 15. The user IF 13, the communication IF 14, and the printing device 15 are all electrically connected to the controller 10. Note that the controller 10 in Fig. 1 is a general term that collectively refers to hardware and software used to control the PC 1, and does not necessarily represent a single piece of hardware that actually exists in the PC 1.

[0012] The CPU 11 executes various processes according to programs read from the memory 12 or based on user operations. The memory 12 stores various programs and data. As shown in FIG. 1, the memory 12 stores, for example, a print control program 21, a binarization program 22, a density threshold 24, and a size threshold 25. Note that the various values ​​included in the density threshold 24 and the size threshold 25 may be incorporated into the print control program 21 in advance, or may be obtained from a server or the like and stored in the memory 12. Details of the programs and data stored in the memory 12 will be described later. The memory 12 is also used as a work area when various processes are executed. The memory 12 may include a buffer provided by the CPU 11.

[0013] Note that an example of memory 12 is not limited to a ROM, RAM, HDD, etc. built into printer 1, but may also be a storage medium that is readable and writable by CPU 11. A computer-readable storage medium is a non-transitory medium. In addition to the above examples, non-transitory media also include recording media such as CD-ROMs and DVD-ROMs. Non-transitory media are also tangible media. On the other hand, an electrical signal carrying a program downloaded from a server on the Internet is a computer-readable signal medium, which is a type of computer-readable medium, but is not included in non-transitory computer-readable storage media.

[0014] The user IF 13 includes hardware for displaying a screen for notifying the user of information and hardware for accepting operations by the user. The user IF 13 may include a touch panel or a combination of a display unit and operation buttons.

[0015] The communication IF 14 includes hardware for communicating with external devices. The communication IF 14 is compatible with a communication standard such as Ethernet (registered trademark), Wi-Fi (registered trademark), or USB. The printer 1 may be equipped with multiple communication IFs 14 compatible with multiple communication standards.

[0016] The printing device 15 includes a device capable of printing based on image data by, for example, an electrophotographic method or an inkjet method. The printing device 15 of the printer 1 of this embodiment is a device equipped with colorants of multiple colors and capable of color printing.

[0017] Next, the operation of the printer 1 according to the embodiment will be described with reference to a flowchart. The following process basically refers to the processing of the CPU 11 in accordance with instructions written in a program. In other words, processes such as "determine," "extract," "select," "calculate," "decide," "identify," "acquire," "receive," and "control" in the following description represent the processing of the CPU 11. The processing by the CPU 11 also includes hardware control using the API of an operating system (hereinafter referred to as "OS"). In this specification, the operation of each program will be described without mentioning the OS. In other words, in the following description, a statement to the effect that "Program B controls Hardware C" may also mean that "Program B controls Hardware C using the API of the OS." Furthermore, the processing of the CPU 11 in accordance with instructions written in a program may be described in abbreviated terms. For example, it may be described as "performed by CPU 11." Furthermore, the processing of the CPU 11 in accordance with instructions written in a program may be described in abbreviated terms, such as "performed by Program A."

[0018] Note that "acquire" is used as a concept that does not require a request. In other words, the process of CPU 11 receiving data without a request is also included in the concept of "CPU acquiring data." Furthermore, "data" in this specification is represented by a bit string that can be read by a computer. Data with the same substantial meaning but different formats are treated as the same data. The same applies to "information" in this specification. Furthermore, "request" and "instruct" are concepts that indicate outputting information indicating a request or an instruction to the other party. Furthermore, information indicating a request or an instruction is also simply referred to as a "request" or "instruction."

[0019] Furthermore, the process by CPU 11 to determine whether information A indicates event B may be conceptually described as "determining whether event B is present from information A." The process by CPU 11 to determine whether information A indicates event B or event C may be conceptually described as "determining whether event B or event C is present from information A."

[0020] The procedure for print job processing will be described with reference to the flowchart in Figure 2. Print job processing is executed by the CPU 11 of the printer 1 based on the print control program 21 when an instruction to execute a print job is accepted. The printer 1 may receive and acquire the print job from an external device via the communication IF 14, or may read and acquire the print job from a USB memory attached to the communication IF 14. Furthermore, if the printer 1 is equipped with a scanner, the printer 1 may acquire image data read by the scanner as the print job.

[0021] CPU 11 begins analyzing the print job for which an execution instruction has been accepted, and acquires image data representing the image to be printed (S101). S101 is an example of acquisition processing. The print job includes, for example, PDL data, which is image data representing the image to be printed, and PJL data representing various printing parameters. The PDL data is, for example, data in a format such as PCL or PDF. Furthermore, CPU 11 allocates a memory area for writing one page of image (S102).

[0022] Then, CPU 11 detects a drawing object from image data indicating an image to be printed, which is included in the print job (S111). CPU 11 analyzes the PDL data to determine whether or not the drawing object is a drawing object. If a drawing object is detected, CPU 11 determines whether or not the detected drawing object is a text object indicating the drawing of characters (S112). S112 is an example of a character detection process.

[0023] If it is determined that the detected drawing object is a text object (S112: YES), the CPU 11 executes a character intermediate data generation process (S115). The procedure of the character intermediate data generation process will be described with reference to the flowchart of FIG.

[0024] In the character intermediate data generation process, the CPU 11 acquires character data, which is various information related to characters shown in the text object to be processed (S201). Specifically, the CPU 11 acquires character data including font information specified in the text object to be processed and a character code indicating the character type. The font information includes information indicating, for example, the font type, character size, character color, and character density. The character size is information indicating the size of the font to be used and corresponds to the size of the character, and the character density corresponds to the darkness of the character.

[0025] Furthermore, the CPU 11 acquires data indicating the outline shape of each character included in the text object based on the character data (S202). The data indicating the outline shape of the character may be stored in the memory 12 of the printer 1 or may be embedded in the print job. The outline shape of the character is also information indicating the position of the edge of the character.

[0026] Furthermore, the CPU 11 acquires information indicating the color of the characters from the character data acquired in S201 (S203). For example, as shown in FIG. 4, PDF format image data 40 may include density information 41, a text drawing command 42, and font information 43. In this example of image data 40, the color of the character string "ABCDEF" specified in the text drawing command 42 is specified by "g" or "G" in the density information 41. In this example, the density information 41 indicates gray characters with a density of 40%. The font information 43 includes information on the font type and character size.

[0027] When printing gray characters in color printing, the CPU 11 determines whether the printer is in a mode that uses only the K colorant (S211). The printer 1, for example, is equipped with four colorants (CMYK), and when printing based on a multi-value color image represented by RGB data, can convert the color information into color information expressed in each of the CMYK colors and print. The printer 1 has, for example, a text mode and a photo mode as printing modes, and can set either one. The printer 1 stores information indicating the set print mode in the memory 12, for example, based on a user selection. The printer 1 may also be able to accept a mode designation from an instruction from a printer driver that transmits a print job.

[0028] When the text mode is set, the printer 1 converts color information for gray portions of the image to be printed into color information expressed using only K color and prints using only K colorants. The text mode is an example of a mode in which gray text in a color image is printed using black colorants. When the photo mode is set, the printer 1 converts color information for gray portions of the image to be printed into color information expressed using CMYK colors and prints using colorants of multiple colors including K. Note that when the photo mode is set, the printer 1 may convert color information for gray portions of the image to be printed into color information expressed using CMY colors and print using colorants of multiple colors not including K. The photo mode is an example of a mode in which gray text in a color image is printed using multiple colorants. Note that for images and text that are not gray, regardless of the mode, the printer 1 converts color information into color information expressed using CMYK or CMY colors and prints using colorants of multiple colors.

[0029] If it is determined that a printing mode using only the K colorant has been selected (S211: YES), CPU 11 determines whether the color of the character to be processed is gray (S212). For example, if the color of the character is represented by RGB data in which the R, G, and B values ​​each range from 0 to 255, and the R, G, and B values ​​are all 0, the color is black. Also, if the R, G, and B values ​​are not 0 but are all equal, the color is gray. In S212, CPU 11 may determine that the color is gray if the R, G, and B values ​​are very close to each other, for example, if the difference between the maximum and minimum values ​​of each value is within 5.

[0030] If the color of the character to be processed is determined to be gray (S212: YES), the CPU 11 determines whether the color of the character is close to black (S213). The CPU 11 may determine that the color of the character is close to black if the average value of the R value, G value, and B value is equal to or less than a predetermined threshold, for example, 51 or less. Note that since the color is determined to be gray in S212, the R value, G value, and B value are very close to each other, and the CPU 11 may determine that the color of the character is close to black if at least one of the R value, G value, and B value is 51 or less, instead of calculating the average value.

[0031] If it is determined that the color of the characters is not close to black (S213: NO), the CPU 11 executes density adjustment processing (S215). The procedure of the density adjustment processing will be described with reference to the flowchart of FIG.

[0032] In the density adjustment process, the CPU 11 acquires the character size and character density for the character to be processed (S301). Information on the character size and character density is included in the character data acquired in S201 of the character intermediate data generation process. For example, in the image data 40 in PDF format shown in FIG. 4, information on the character size is included in the font information 43, and information on the character density is included in the density information 41.

[0033] Furthermore, the CPU 11 reads from the memory 12 a first size threshold 251 included in the size threshold 25 (see FIG. 1) (S302). The first size threshold 251 is an example of a predetermined size. The CPU 11 then determines whether the character size acquired in S301 is equal to or greater than the first size threshold 251 read in S302 (S303). The first size threshold 251 is, for example, 7 points.

[0034] If it is determined that the character size is equal to or larger than the first size threshold 251 (S303: YES), the CPU 11 fills the inside of the character outline shape obtained in S202 of the character intermediate data generation process (see Figure 3) with the character color obtained in S203, and generates intermediate data that is multi-value bitmap data (S304).

[0035] The intermediate data is, for example, RGB data that expresses color for each pixel using the gradation values ​​of each RGB color. If the image data included in the print job is not RGB data, the CPU 11 may convert it to RGB data and generate intermediate data. The CPU 11 stores the generated intermediate data in a temporary area of ​​the memory 12. If the object is a text object representing a character string containing multiple characters, the CPU 11 generates intermediate data for each character and stores the intermediate data for each character in a temporary area of ​​the memory 12.

[0036] Furthermore, CPU 11 determines whether the print resolution is low (S311). Information on the print resolution is included, for example, in the print settings of the print job. CPU 11 determines that the print resolution is low if it is lower than a predetermined resolution. The predetermined resolution is, for example, 600 dpi. In this case, for example, if the print resolution is 300 dpi, CPU 11 determines that it is low resolution. Note that if the print resolution setting is not included in the print settings of the print job, CPU 11 may obtain the default print resolution set in printer 1 and make the determination.

[0037] If it is determined that the print resolution is equal to or higher than the predetermined resolution and is not low (S311: NO), the CPU 11 executes a dashed line type determination process (S312). The procedure of the dashed line type determination process will be described with reference to the flowchart of FIG.

[0038] In the printer 1 of this embodiment, dashed lines may be added along the data representing the outline shape of characters in the generated intermediate data. The added dashed lines are 1-dot wide dashed lines composed of one or more dots with 100% density and one or more dots with 0% density arranged alternately. A dot with 100% density has an R value, a G value, and a B value of 0, and will be referred to as a "black dot" below. A dot with 0% density has an R value, a G value, and a B value that are all maximum, and will be referred to as a "white dot" below.

[0039] In the dashed line type determination process, the CPU 11 determines the type of dashed line to be added. First, the CPU 11 reads out the first density threshold 241 and the second density threshold 242 included in the density threshold 24 (see FIG. 1) from the memory 12 (S401). The first density threshold 241 is an example of a first threshold. The second density threshold 242 is an example of a second threshold.

[0040] The first density threshold 241 is higher than 70%, and is preferably in the range of 70% to 95%, and more preferably in the range of 85% to 95%. The first density threshold 241 is, for example, 90%. The second density threshold 242 is lower than the first density threshold 241, is lower than 60%, and is preferably in the range of 35% to 60%, and more preferably in the range of 35% to 45%. The second density threshold 242 is, for example, 40%. Note that the second density threshold 242 may be any value lower than the first density threshold 241, but if it is too low, the processing load will be large even though the effect of jaggies is slight.

[0041] The CPU 11 determines whether the character density acquired in S301 of the density adjustment process (see FIG. 5) is equal to or less than the first density threshold 241 and equal to or greater than the second density threshold 242 (S402). Note that the determination in S402 may be a determination that does not include cases where the character density is equal to any density threshold included in the density threshold 24. If it is determined that the character density is equal to or less than the first density threshold 241 and equal to or greater than the second density threshold 242 (S402: YES), the CPU 11 determines a dashed line type candidate that corresponds to the character density (S405).

[0042] Specifically, as shown in Figure 7, the CPU 11 determines, based on character density, dashed line types that have a larger black-to-white ratio as the character density increases. The black-to-white ratio of a dashed line is the ratio of the length of each line segment to the length of each non-line segment along the length of the dashed line. A line segment is a portion of a dashed line formed by consecutive black dots. A non-line segment is a portion located between line segments and formed by consecutive white dots.

[0043] The length of a line portion is the result of multiplying the number of consecutive black dots by the size of each dot (length in the linear direction), and is proportional to the number of consecutive black dots. The length of a non-line portion is the result of multiplying the number of consecutive white dots by the size of each dot, and is proportional to the number of consecutive white dots. The size of each dot in an image is equal for black dots and white dots. In other words, the black-white ratio of a dashed line can be expressed as the ratio of the number of consecutive black dots that make up a line portion to the number of consecutive white dots that make up a non-line portion. For example, the black-white ratio of a dashed line in which n black dots and 1 white dot are alternately arranged is n, where n is a natural number. It can also be said that the length of a line portion corresponds to the number of consecutive black dots, and the length of a non-line portion corresponds to the number of consecutive white dots.

[0044] When the character density is 90% or less but greater than 80%, the CPU 11 selects a type A broken line with a black-white ratio of 4 as a broken line type candidate. A type A broken line is, for example, a broken line in which line portions with 4 black dots and non-line portions with 1 white dot are alternately arranged. When the character density is 80% or less but greater than 60%, the CPU 11 selects a type B broken line with a black-white ratio of 3 as a broken line type candidate. A type B broken line is, for example, a broken line in which line portions with 3 black dots and non-line portions with 1 white dot are alternately arranged. When the character density is 60% or less but greater than 50%, the CPU 11 selects a type C broken line with a black-white ratio of 2 as a broken line type candidate. A type C broken line is, for example, a broken line in which line portions with 2 black dots and non-line portions with 1 white dot are alternately arranged. When the character density is 50% or less and 40% or more, the CPU 11 selects, as a candidate dashed line type, a type D dashed line with a black-to-white ratio of 1. A type D dashed line is, for example, a dashed line in which line portions made up of two black dots and non-line portions made up of two white dots are arranged alternately.

[0045] That is, when the character density is a first density, the CPU 11 selects a dashed line type candidate that has a lower black-white ratio compared to a second density that is higher than the first density. For example, when the character density is 50%, the CPU 11 selects a dashed line type candidate that has a black-white ratio of 1, and when the character density is 90%, the CPU 11 selects a dashed line type candidate that has a black-white ratio of 4. 50% is an example of the first density, and 90% is an example of the second density. Note that there are countless dashed lines with the same black-white ratio but different lengths of line and non-line portions, but the CPU 11 selects dashed lines with three or fewer consecutive white dots as dashed line type candidates.

[0046] If dashed lines are added to characters with low character density, the dashed lines may emphasize the edges, which may result in a deterioration in quality. For characters with low character density, printer 1 adds dashed lines with a low ratio of line parts to non-line parts, thereby avoiding edge emphasis. On the other hand, for characters with high character density, adding dashed lines is unlikely to emphasize the edges. For characters with high character density, printer 1 adds dashed lines with a high ratio of line parts to non-line parts, thereby prioritizing the suppression of jaggies.

[0047] Then, the CPU 11 reads the second size threshold 252 from the memory 12 (S411), and determines whether the character size acquired in S301 of the density adjustment process (see FIG. 5) is equal to or greater than the read second size threshold 252 (S412). The second size threshold 252 is, for example, 10.5 points.

[0048] If it is determined that the character size is equal to or greater than the second size threshold 252 (S412: YES), the CPU 11 determines whether the font type specified in the text object to be printed is a font type that includes thin lines (S414). Examples of font types that include thin lines include font types that include characters with many strokes, such as Mincho, and font types that include thin portions, such as serifs and hair script. For example, the CPU 11 may determine that a font type includes thin lines if the font type is a serif type and is not italic or bold. The CPU 11 may, for example, store in advance a list of font types that include thin lines, such as Times New Roman and Mincho, or may obtain the list by inquiring of an external device, such as a server.

[0049] Furthermore, when it is determined that the character size is not equal to or larger than the second size threshold 252 (S412: NO), the CPU 11 also determines whether the specified font is a font type that includes thin lines (S416). The determination in S416 is the same as the determination in S414.

[0050] Then, if the character size is equal to or greater than the second size threshold 252 and the font type is determined to be a type that includes thin lines (S414: YES), or if the character size is smaller than the second size threshold 252 and the font type is determined not to be a type that includes thin lines (S416: NO), the CPU 11 adds dashed lines of the dashed line type determined in S405 to the intermediate data generated in S304 of the density adjustment process, along the outline shape of the character, outside the edge of the character (S421). S421 is an example of dashed line addition processing. The CPU 11 adds dashed lines outside the intermediate data of the character without overlapping them with the intermediate data of the character.

[0051] Specifically, the CPU 11 arranges the dashed line of the determined dashed line type along the outline shape of the character acquired in S202 of the character intermediate data generation process (see FIG. 3) to generate bitmap data of the dashed line outline shape. Furthermore, the CPU 11 adds the bitmap data of the dashed line to the intermediate data, which is the bitmap data generated in S304 of the density adjustment process. As a result, intermediate data is generated in which dashed lines are added along the outline of the character so as to surround the character area 31. The CPU 11 stores the generated intermediate data in a temporary area of ​​the memory 12.

[0052] For example, as shown in a partial example in FIG. 8, CPU 11 adds dashed lines to dashed line area 32, which is a one-dot-wide area that is adjacent to the periphery of character area 31, an image showing characters, and is located outside character area 31. As described above, the type of dashed line varies depending on the character density. FIG. 8(A) is an example in which a type D dashed line has been added to dashed line area 32. FIG. 8(B) is an example in which a type C dashed line has been added to dashed line area 32. FIG. 8(C) is an example in which a type B dashed line has been added to dashed line area 32. Character area 31 is gray with varying density, and the black dots in dashed line area 32 are represented in black.

[0053] The intermediate data in which dashed lines are added along the character outlines so as to surround the character area 31 does not have to be a single piece of data. That is, this intermediate data may be a combination of the character bitmap data generated in S304 and dashed line bitmap data. Furthermore, instead of separately generating and adding bitmap data representing the dashed lines of the character outline shape, the CPU 11 may directly add the dashed lines of the determined dashed line type to the intermediate data generated in S304.

[0054] 8 shows an example in which dashed line region 32 is provided outside the edge of character region 31, but dashed line region 32 to which a dashed line is added may be a region of one dot width on the outermost periphery inside the edge. In other words, dashed line region 32 may be included in character region 31. In this case, CPU 11 overwrites the dashed line on the outermost periphery of character region 31 along the outline shape of the character.

[0055] On the other hand, if the character size is equal to or greater than the second size threshold 252 and it is determined that the font type does not include thin lines (S414: NO), the CPU 11 does not change the number of white dots in the candidate dashed line type, but adds 1 to the number of black dots (S415). That is, the CPU 11 increases the black-to-white ratio of the dashed line. As a result, for characters of a font type with a large character size that does not include thin lines, the CPU 11 determines a dashed line type with a larger black-to-white ratio than for characters of a font type with a large character size that includes thin lines.

[0056] Furthermore, if the character size is smaller than the second size threshold 252 and it is determined that the font type includes thin lines (S416: YES), the CPU 11 does not change the number of black dots in the candidate dashed line type, but adds 1 to the number of white dots (S417). That is, the CPU 11 reduces the black-white ratio of the dashed line. As a result, for characters of a font type with a small character size and including thin lines, the CPU 11 determines a dashed line type with a smaller black-white ratio than for characters of a font type with a small character size but not including thin lines.

[0057] After S415 or S417, the CPU 11 adds a dashed line of the dashed line type determined in S415 or S417 along the contour of the intermediate data generated in S304 of the density adjustment process (see FIG. 5) (S421).

[0058] In other words, when a font type includes thin lines, dashed lines with a lower ratio of line to non-line parts are added compared to when a font type does not include thin lines. Adding dashed lines to thin lines can make the dashed lines stand out and cause distortion, which can degrade quality. When a font type includes thin lines, printer 1 adds dashed lines with a lower black-to-white ratio compared to when a font type does not include thin lines. In other words, printer 1 widens the gaps in dashed lines added to characters with thin character shapes, which is expected to reduce quality degradation.

[0059] After S421, the CPU 11 ends the dashed line type determination process and returns to the density adjustment process. If the CPU 11 determines that the character density is higher than the first density threshold 241 or lower than the second density threshold 242 (S402: NO), the CPU 11 does not add a dashed line, ends the dashed line type determination process, and returns to the density adjustment process. If the CPU 11 does not add a dashed line, the intermediate data generated in S304 is stored in a temporary area of ​​the memory 12.

[0060] When the character density is high, even if dithering is performed in a later step, large chips are unlikely to occur at the edges of the characters, and jaggedness is unlikely to occur. Furthermore, when the character density is low, chipped edges are less noticeable, and jaggedness is less likely to be a problem. The printer 1 does not add dashed lines when the character density is higher than the first density threshold 241 or lower than the second density threshold 242. Therefore, in these cases, the process of adding dashed lines is avoided, reducing the processing load.

[0061] On the other hand, when the character density is an intermediate tone between the first density and the second density, CPU 11 adds dashed lines. In particular, the lower the character density, the lower the ratio of line portions to non-line portions of the dashed lines added. This prevents excessive emphasis of character edges caused by surrounding the character with dashed lines. In contrast, when the character density is high, the edges are less likely to be emphasized even if the character is surrounded by dashed lines with a high ratio of line portions to non-line portions. In this case, dashed lines with a high ratio of line portions to non-line portions are added, which prioritizes suppressing the occurrence of jaggies.

[0062] Returning to the explanation of the density adjustment process in Fig. 5, after the dashed line type determination process in S312, the CPU 11 ends the density adjustment process and returns to the character intermediate data generation process (Fig. 3).

[0063] Furthermore, if the CPU 11 determines that the print resolution is low (S311: YES), it does not add dashed lines, terminates the density adjustment process, and returns to the character intermediate data generation process. When the print resolution is low, for example, each dot in the binary image generated by dithering from the original image shown in FIG. 9A becomes a large dot, as shown in FIG. 9B. Therefore, for example, if dashed line region 32 is added along the outside of character region 31, as shown in FIG. 9C, the dashed line may become conspicuous, resulting in a deterioration in quality. In this embodiment, when the print resolution is low, the printer 1 does not add dashed lines even if the character size is equal to or greater than first size threshold 251, thereby reducing quality degradation.

[0064] On the other hand, if it is determined that the character size is smaller than the first size threshold 251 (S303: NO), the CPU 11 determines whether the font type includes thin lines (S321). The determination in S321 may be the same as that in S414 or S416 of the dashed line type determination process, or may be based on different criteria. For example, characters smaller than 7 points are likely to include thin lines, and this possibility is even higher for font types that include thin lines.

[0065] If it is determined that the font type includes thin lines (S321: YES), the CPU 11 reads out the third density threshold 243 of the density threshold 24 (see FIG. 1) from the memory 12 (S322). The third density threshold 243 is, for example, 20%. The CPU 11 then determines whether the character density acquired in S301 is equal to or less than the read third density threshold 243 (S323). If it is determined that the character density is equal to or less than the third density threshold 243 (S323: YES), the CPU 11 increases the character density (S324). S324 is an example of a density-increasing process. The CPU 11 sets the character density to, for example, the third density threshold 243 + 5%.

[0066] After S324, the CPU 11 fills the inside of the outline shape of the character acquired in S202 of the character intermediate data generation process (see FIG. 3) with the color of the character acquired in S203, but with a darker character density, to generate intermediate data that is multi-value bitmap data (S325).

[0067] When a font type includes thin lines and the character density is low, for example, a binary image generated by dithering from the original image shown in FIG. 10(A) may tend to be broken up, especially in thin portions, as shown in FIG. 10(B), making the characters unrecognizable. In this case, adding a dashed line region 32 around the outside of the character region 31, as shown in FIG. 10(C), is unlikely to improve quality. In the printer 1 of this embodiment, when thin characters have low character density, the original image to be subjected to dithering is an image in which the character density is increased, for example, from the original image shown in FIG. 10(A) to the image shown in FIG. 10(D). A binary image generated by dithering from the original image with the increased character density is less likely to be broken up, even in thin portions of the characters, as shown in FIG. 10(E), reducing quality degradation.

[0068] On the other hand, if it is determined that the font type does not include thin lines (S321: NO), or if it is determined that the character density is higher than the third density threshold 243 (S323: NO), the CPU 11 fills the inside of the character outline shape acquired in S202 of the character intermediate data generation process (see FIG. 3) with the character color acquired in S203, and generates intermediate data that is multi-value bitmap data (S325). In this case, the CPU 11 does not change the character density.

[0069] Small-sized characters contain thin lines to some extent, even if the font type does not include thin lines. Even if the lines are thin, as long as the character density is not low, a binary image generated by dithering from the original image shown in FIG. 11(A), for example, as shown in FIG. 11(B), is likely to produce a seamless binary image. Adding dashed lines in this case would result in thicker lines, as shown in FIG. 11(C). In this embodiment, the printer 1 generates intermediate data with the character density unchanged without adding dashed lines, even if the character size is small, as long as the font type does not include thin lines, or if the font type includes thin lines but the character density is not low, thereby reducing quality degradation.

[0070] After S325, the CPU 11 ends the density adjustment process and returns to the character intermediate data generation process of Fig. 3. In the character intermediate data generation process of Fig. 3, after the density adjustment process of S215 is completed, the CPU 11 ends the character intermediate data generation process and returns to the print job process of Fig. 2.

[0071] The remaining part of the character intermediate data generation process in Fig. 3 will be explained. If it is determined that the character color is close to black (S213: YES), CPU 11 fills the inside of the character outline shape acquired in S202 with black, i.e., a color in which the R value, G value, and B value are all 0, and generates intermediate data that is multi-value bitmap data (S221). The black intermediate data will result in a binary image consisting of only black dots, even when a binary image is generated by dithering in a later procedure.

[0072] If the character color is close to black, printing it as black will not change the user's perception. If the printer 1 determines that the character color is close to black, it prints the character as black without adding dashed lines, which prevents jagged edges and thick characters and also reduces the processing load. On the other hand, if the printer 1 determines that the character color is not close to black, it adds dashed lines as described above, which is expected to result in characters that are easy to read based on the character color.

[0073] If the CPU 11 determines that the mode using only the K colorant for printing gray areas is not selected (S211: NO), or if the CPU 11 determines that the color of the character to be processed is not gray (S212: NO), the CPU 11 fills the inside of the character outline shape acquired in S202 with the character color acquired in S203, and generates intermediate data that is multi-value bitmap data (S222). In this case, the CPU 11 does not add dashed lines to the characters.

[0074] In a mode using multiple colorants or when printing characters in a color other than gray, the printer 1 performs dithering for each color of colorant and generates a binarized image for each color. In this case, the printer 1 performs dithering using a different dither pattern for each color, so the dot positions are likely to differ for each color, making it less likely that jaggies will occur. In a mode using multiple colorants or when printing characters in a color other than gray, the printer 1 does not add dashed lines, reducing the processing load.

[0075] After S221 or S222, the CPU 11 ends the character intermediate data generation process and returns to the print job process.

[0076] Returning to the description of the print job processing in Fig. 2, the CPU 11 copies the intermediate data held in the temporary area of ​​the memory 12 in the character intermediate data generation processing of S115 to the drawing position specified for the text object in the memory area allocated in S102 (S116). In S116, the multi-value intermediate data generated based on the text object is arranged in the memory area for one page.

[0077] On the other hand, if it is determined that the detected drawing object is not a text object (S112: NO), the CPU 11 generates intermediate data for each object (S117) and copies it to the drawing position (S116).

[0078] Then, the CPU 11 determines whether data indicating the end of the page has been acquired (S118). If it is determined that the end of the page is not reached (S118: NO), the CPU 11 proceeds to S111 and further detects drawing objects.

[0079] CPU 11 performs steps S115 to S117 for each drawing object included in one page of image data. As a result, the multi-valued intermediate data of each object included in one page is respectively arranged in a memory area, and a multi-valued image for one page is generated. In other words, S116 is a process for generating a multi-valued image, and is an example of a multi-valued image generation process.

[0080] If it is determined that data indicating the end of the page has been acquired (S118: YES), the CPU 11 performs color conversion on the multi-value image for one page generated in the memory area (S121). For example, if the printing device 15 of the printer 1 is a device that prints using four colorants of CMYK, the CPU 11 converts the RGB data into CMYK data. The CPU 11 performs color conversion using a pre-installed color conversion profile. As a result, a multi-value image for one page expressed in CMYK data is generated. S121 may be an example of a multi-value image generation process.

[0081] The CPU 11 binarizes the color-converted multi-value image to generate a binary image (S122). S122 is an example of binarization processing. Binarization is processing in which a multi-value image for each color is converted into two gradations to generate a binary image for each color. The CPU 11 generates binary bitmap data based on the multi-value bitmap data by executing, for example, dither processing using a dither matrix using the binarization program 22 (see FIG. 1).

[0082] Specifically, the CPU 11 determines whether each pixel of the multi-value image should be an on dot or an off dot for each color. An on dot is a pixel where a dot is formed using a colorant in the printing device 15, and an off dot is a pixel where a dot is not formed. For example, the CPU 11 forms an on dot if the gradation value of the multi-value image is equal to or greater than the value indicated in the dither matrix, and forms an off dot if the gradation value of the multi-value image is smaller. The dither matrix applied may be different for each color.

[0083] When a binary image is generated based on a multi-valued image of a character to which a dashed line has been added, as in the example of FIG. 8, the binary image includes a character region 31 processed by a dither matrix and a dashed line region 32 formed by the added dashed line, as shown in a portion of FIG. 12. When a dashed line is added in the character intermediate data generation process, the line portion of the added dashed line is made up of black dots with a density of 100%, so the line portion becomes on-dot and the non-line portion becomes off-dot. In other words, the shape of the dashed line is maintained even after the binarization process. Furthermore, because a dashed line with a width of 1 dot is added, character thickening is suppressed. Furthermore, because the black-to-white ratio of the dashed line is determined according to the density of the character, excessive emphasis on the character edges is avoided.

[0084] A character region 31 of a gray character with a density of 50% becomes a dither pattern corresponding to a density of 50%, for example, as shown in Fig. 12(A). A dashed line with a black-to-white ratio of 1 is formed in a dashed line region 32 along the contour of this character region 31. A character region 31 of a gray character with a density of 60% becomes a dither pattern corresponding to a density of 60%, for example, as shown in Fig. 12(B), and a dashed line with a black-to-white ratio of 2 is formed in the dashed line region 32. A character region 31 of a gray character with a density of 80% becomes a dither pattern corresponding to a density of 80%, for example, as shown in Fig. 12(C).

[0085] The binarization program 22 may use error diffusion processing instead of dithering. Furthermore, if the printer 1 is equipped with binarization hardware, the printer 1 may use the binarization hardware to generate binarized data. The binarization hardware is, for example, hardware that binarizes a multi-valued image while taking into account edges that appear in the image. The binarization hardware may, for example, determine whether a pixel is likely to be an edge based on the color difference between the target pixel and its surrounding pixels, and set the pixel to dot-on if it is highly likely to be an edge and has a high density.

[0086] The CPU 11 passes the generated binary image to the printing device 15 (S123) and causes printing to be performed. S123 is an example of printing processing. The CPU 11 may also generate data in a format suitable for the printing device 15 based on the binary image and pass the data to the printing device 15. The printing device 15 performs printing based on the passed binary image.

[0087] Then, the CPU 11 determines whether the processing of the print job has been completed (S124). If it is determined that the processing has not been completed (S124: NO), the CPU 11 proceeds to S103 to process the image data of the next page. If it is determined that the processing of the print job has been completed (S124: YES), the CPU 11 ends the print job processing.

[0088] As explained in detail above, the printer 1 of the embodiment adds dashed lines to the edges of characters included in the image to be printed before generating a multi-valued image. This is expected to fill in some of the large chips exposed at the edges of the binarized characters, making the chips smaller and less noticeable, thereby suppressing the occurrence of jaggies.

[0089] Furthermore, if the character size is small, adding dashed lines can make the lines stand out and potentially degrade the quality. The printer 1 of this embodiment adds dashed lines to characters that are larger than a certain size, but does not add dashed lines to small characters, thereby reducing the degradation of quality.

[0090] Furthermore, when printing characters using multiple colorants, the dot placement is shifted for each color, which tends to reduce the amount of white space, making it less likely that chipped edges will occur in the characters. The printer 1 of this embodiment adds dashed lines to characters printed using a single colorant, but does not add dashed lines to characters printed using multiple colorants, thereby reducing the processing load.

[0091] In the density adjustment process shown in FIG. 5, dashed lines are added when the character size is equal to or greater than the first size threshold 251 and is not low resolution. However, even if the character size is equal to or greater than the first size threshold 251, dashed lines may not be added if the font type includes thin lines. Specifically, instead of making the determination in S303, CPU 11 may determine whether the font type includes thin lines. If the font type does not include thin lines, CPU 11 may proceed to S304, and if the font type does include thin lines, CPU 11 may proceed to S322. In the case of thin character shapes, dashed lines are more noticeable than in the case of non-thin character shapes of the same density, which may result in deterioration of quality. If the character shape is thin, even if dashed lines are not added, deterioration of quality is reduced.

[0092] Next, an example will be described in which an information processing device capable of sending a print job to a printer executes part of the same process as the print job process described above (see FIG. 2). For example, as shown in FIG. 13, a personal computer (hereinafter referred to as "PC") 5 is connected to a printer 6 and is a device capable of sending a print job to the printer 6. The PC 5 is an example of an information processing device. The printer 6 is a device capable of printing based on a received print job, and may or may not have a function for adding dashed lines similar to that of the printer 1 described above.

[0093] As shown in FIG. 13, the PC 5 includes a controller 50 including a CPU 51 and a memory 52. ​​The PC 5 further includes a user IF 53 and a communication IF 54. The CPU 51 is an example of a computer. The memory 52 stores various programs and data, including an OS 521 and a printer driver 522. The printer driver 522 is an example of a program corresponding to the printer 6.

[0094] The procedure for print job processing executed by PC 5 will be described with reference to the flowchart in Fig. 14. This print job processing is executed by CPU 51 of PC 5 based on printer driver 522 in response to receiving a print instruction from an application program that edits a document or displays an image, for example. Note that, below, steps similar to those in the print job processing executed by printer 1 described above are assigned the same reference numerals, and the description will be simplified.

[0095] Based on the printer driver 522, the CPU 51 of the PC 5 executes S101 to S118. The CPU 51 acquires image data indicating an image to be printed from the application program that has accepted the print instruction (S101), and if a text object is detected from the image data (S112: YES), executes character intermediate data generation processing. S101 is an example of acquisition processing. S112 is an example of character detection processing.

[0096] The character intermediate data generation process is the same as the process executed by the printer 1 described above. The PC 5 may, for example, inquire of the printer 6 to determine whether the print mode is character mode or photo mode. Alternatively, the print mode information may be included in the print job. If the mode is character mode and the character color is gray that is not close to black (S213: NO), the CPU 51 executes the density adjustment process shown in FIG. 5.

[0097] In the density adjustment process, the CPU 51 determines whether to add dashed lines and, if so, what type of dashed lines to add, based on character data such as character size, character density, and font type, as well as print resolution, and generates intermediate data for each character. Specifically, the CPU 51 executes the dashed line type determination process shown in FIG. 6 when the character size is equal to or greater than the first size threshold 251 and the print resolution is not low. The character data may be included in the print job or may be obtained by querying the printer 6, a server, or the like. Information on the print resolution may be included in the print job or may be obtained by querying the printer 6.

[0098] If the character density is equal to or greater than the first density threshold 241 and equal to or less than the second density threshold 242 (S402: YES), the CPU 51 determines a dashed line type according to the character density and adds dashed lines to the character edges (S421). The dashed line type determination process S421 is an example of dashed line addition processing. As with the processing of the printer 1, the CPU 51 selects a dashed line type with a larger black-to-white ratio as the character density increases.

[0099] Furthermore, the CPU 51 corrects the black-white ratio of the dashed line to be added depending on whether the character size is equal to or greater than the second size threshold 252 and whether the font type specified in the character data is a font type for thin characters that includes thin lines. Specifically, if the character size is equal to or greater than the second size threshold 252, the CPU 51 increases the black-white ratio compared to when the character size is smaller than the second size threshold 252. Furthermore, if the character size is thin, the CPU 51 decreases the black-white ratio compared to when the character size is not thin.

[0100] When the CPU 51 has finished generating one page of intermediate data (S118: YES), it outputs a print command including the generated intermediate data to the printer 6 and instructs the printer 6 to execute printing (S401). S401 is an example of output processing. The printer 6 executes printing based on the print command output in S401. When the printer 6 receives a print command including intermediate data that is a multi-valued image as image data to be printed, it can generate a binary image and execute printing.

[0101] Note that instead of transmitting the intermediate data one page at a time, the PC 5 may generate intermediate data for all pages of the print job and then transmit the intermediate data for all pages together to the printer 6. The PC 5 may also perform color conversion processing and binarization processing and transmit the binarized image data to the printer 6.

[0102] As explained above in detail, even in a configuration in which the PC 5 generates intermediate data and outputs it to the printer 6, it is possible to add dashed lines to the edges of characters included in the image to be printed before generating a multi-valued image, just as in the case in which the intermediate data is generated by the printer 1. In this way, the occurrence of jaggies is suppressed and deterioration of quality is reduced.

[0103] In the density adjustment process executed by the PC 5, even if the character size is equal to or larger than the first size threshold 251, if the font type includes thin lines, dashed lines may not be added.

[0104] Note that the embodiments are merely examples and do not limit the present invention in any way. Therefore, the technology disclosed in this specification can naturally be improved and modified in various ways without departing from the spirit and scope of the present invention. For example, the printer is not limited to a single-function printer, but can also be applied to any device with a color printing function, such as a multifunction printer, copier, or fax machine. Furthermore, the device that sends a print job to the printer is not limited to a PC, but can also be a smartphone, tablet computer, or server computer.

[0105] Furthermore, the specific values ​​of the density thresholds and size thresholds presented in the embodiments are merely examples and are not limiting. The thresholds may vary, for example, depending on the printer model, or the presence or absence of a background or shadow. While the embodiments describe the thresholds as being stored in memory 12, they may also be user-configurable.

[0106] In the embodiment, dashed lines with different black-white ratios are added depending on the density of the text object, but the same dashed lines may be added regardless of the density. However, selecting the black-white ratio of the dashed lines depending on the density prevents the edges from being too conspicuous. Also, although an example of four different black-white ratios depending on the character density has been shown, the number is not limited to four.

[0107] Furthermore, in the embodiment, dashed lines with a line width of 1 dot are added, but this is not limited to this. For example, dashed lines with different line widths may be added depending on the print resolution and character size. Specifically, a 1-dot width is desirable for devices with medium resolution, but a 2-3 dot wide dashed line may be used for devices with high resolution. However, if the dashed line width is too thick, the characters may appear to be outlined, so a 1-dot wide dashed line is desirable.

[0108] In addition, although the embodiment has been described as adding dashed lines with a density of 100%, this is not limited to this. For example, dashed lines with a different density, at least higher than the density of the characters, may be added depending on the density of the characters. However, if dashed lines with a density other than 100% are added, there is a possibility that the dashed lines will also be subject to dithering, so it is preferable to use dashed lines with a density of 100%, which will not be subject to dithering.

[0109] Furthermore, in the embodiment, the determination of the character size and whether or not the character contains thin lines is made based on the font type information, but it may be made for each character.

[0110] In addition, in the embodiment, the printer 1 does not add dashed lines when the printer is in a mode for printing gray characters using multiple colorants, but dashed lines may be added. In other words, step S211 of the intermediate data generation process may be omitted. Also, in the embodiment, the printer 1 changes the color of the characters to black and does not add dashed lines when the color is close to black, but dashed lines may be added when the characters are not black even if they are close to black.

[0111] Furthermore, when generating a multi-level image on a PC connected to a printer, the PC may have a so-called driverless configuration in which the OS is pre-installed with a general-purpose printing program and does not use a printer driver. The PC may also have a printer-specific program installed in addition to the general-purpose program installed in the OS. In this case, the PC may generate the multi-level image using that program. Even in this configuration, the program can add dashed lines to the outlines of characters to reduce jagged edges.

[0112] Furthermore, in any flowchart disclosed in the embodiments, the execution order of multiple processes in any multiple steps can be arbitrarily changed or can be executed in parallel, as long as no contradiction occurs in the processing content.

[0113] The processes disclosed in the embodiments may be executed by hardware such as a single CPU, multiple CPUs, or ASIC, or a combination thereof. The processes disclosed in the embodiments may be realized in various ways, such as a recording medium on which a program for executing the processes is recorded, or a method. [Explanation of symbols]

[0114] 1. Printer 10 Controller 15 Printing Devices 5 PC 51 CPU

Claims

1. A printer comprising a printing device and a controller, The controller an acquisition process for acquiring image data; a multi-value image generation process for generating a multi-value image based on the image data acquired in the acquisition process; a binarization process for converting the multi-valued image generated by the multi-valued image generation process into a binary image; a printing process that causes the printing device to perform printing based on the binarized image generated by the binarization process; is executable, The controller further comprises: After the acquisition process is performed and before the multi-value image generation process is performed, a character detection process is performed to detect character data indicating characters from the image data acquired in the acquisition process; if the size of the character indicated in the character data detected in the character detection process is equal to or larger than a predetermined size, a dashed line addition process is executed to add dashed lines to edges of the character indicated in the character data detected in the character detection process, and in the multi-value image generation process, the multi-value image is generated based on the character to which the dashed lines have been added in the dashed line addition process; If the size of the character indicated in the character data detected in the character detection process is smaller than the predetermined size, the dashed line addition process is not executed. The printer is configured as follows:

2. 2. The printer according to claim 1, The controller if the size of the character indicated in the character data detected in the character detection process is equal to or larger than a predetermined size and the character indicated in the character data is not a thin character shape, then the dashed line addition process is executed, and in the multi-value image generation process, the multi-value image is generated based on the character to which the dashed line has been added in the dashed line addition process; If the size of the characters shown in the character data detected in the character detection process is smaller than the predetermined size, or if the characters shown in the character data have a thin character shape, the dashed line addition process is not performed, and a density increase process is performed to increase the density of the characters shown in the character data detected in the character detection process, and in the multi-value image generation process, the multi-value image is generated based on the characters whose density has been increased by the density increase process. The printer is configured as follows:

3. 2. The printer according to claim 1, the dashed line added by the dashed line adding process has a plurality of line portions and non-line portions between the line portions, and when the character size is a first size, the ratio of the line portions to the non-line portions is lower than when the character size is a second size larger than the first size; The printer is configured as follows:

4. 2. The printer according to claim 1, the dashed line added by the dashed line addition process has a plurality of line portions and non-line portions between the line portions, and when the character shown in the character data detected by the character detection process has a thin character shape, the ratio of the line portions to the non-line portions is lower than when the character has a non-thin character shape; The printer is configured as follows:

5. 2. The printer according to claim 1, The controller If the size of the characters indicated in the character data detected in the character detection process is equal to or larger than a predetermined size and the print resolution is equal to or larger than a predetermined resolution, the dashed line addition process is executed, and in the multi-value image generation process, the multi-value image is generated based on the characters to which the dashed lines have been added in the dashed line addition process; Even if the size of the characters indicated in the character data detected in the character detection process is equal to or larger than the predetermined size, if the print resolution is lower than the predetermined resolution, the dashed line addition process is not executed, If the size of the character indicated in the character data detected in the character detection process is smaller than the predetermined size, the dashed line addition process is not executed. The printer is configured as follows:

6. A printer comprising a printing device and a controller, The controller an acquisition process for acquiring image data; a multi-value image generation process for generating a multi-value image based on the image data acquired in the acquisition process; a binarization process for converting the multi-valued image generated by the multi-valued image generation process into a binary image; a printing process that causes the printing device to perform printing based on the binarized image generated by the binarization process; is executable, The controller further comprises: After the acquisition process is performed and before the multi-valued image generation process is performed, a character detection process for detecting character data indicating characters from the image data acquired in the acquisition process; a dashed line addition process for adding dashed lines to edges of characters shown in the character data detected in the character detection process; Run the dashed line added by the dashed line addition process has a plurality of line portions and non-line portions between the line portions, and when the character shown in the character data detected by the character detection process has a thin character shape, the ratio of the line portions to the non-line portions is lower than when the character has a non-thin character shape; The printer is configured as follows:

7. A printer comprising a printing device and a controller, The controller an acquisition process for acquiring image data; a multi-value image generation process for generating a multi-value image based on the image data acquired in the acquisition process; a binarization process for converting the multi-valued image generated by the multi-valued image generation process into a binary image; a printing process that causes the printing device to perform printing based on the binarized image generated by the binarization process; is executable, The controller further comprises: After the acquisition process is performed and before the multi-value image generation process is performed, a character detection process is performed to detect character data indicating characters from the image data acquired in the acquisition process; If the print resolution is equal to or greater than a predetermined resolution, a dashed line addition process is executed to add dashed lines to edges of characters indicated in the character data detected in the character detection process, and in the multi-value image generation process, the multi-value image is generated based on the characters to which the dashed lines have been added in the dashed line addition process; If the print resolution is lower than the predetermined resolution, the dashed line addition process is not executed. The printer is configured as follows:

8. A printer comprising a printing device and a controller, The controller an acquisition process for acquiring image data; a multi-value image generation process for generating a multi-value image based on the image data acquired in the acquisition process; a binarization process for converting the multi-valued image generated by the multi-valued image generation process into a binary image; a printing process that causes the printing device to perform printing based on the binarized image generated by the binarization process; is executable, The controller further comprises: After the acquisition process is performed and before the multi-value image generation process is performed, a character detection process is performed to detect character data indicating characters from the image data acquired in the acquisition process; if the character indicated by the character data detected in the character detection process is not a thin character, a dashed line addition process is executed to add dashed lines to edges of the character indicated by the character data detected in the character detection process, and in the multi-value image generation process, the multi-value image is generated based on the character to which the dashed lines have been added in the dashed line addition process; If the character detected in the character data by the character detection process is a thin character, the dashed line addition process is not executed. The printer is configured as follows:

9. 9. The printer according to claim 8, The controller If the character indicated by the character data detected in the character detection process is not a thin character, the dashed line addition process is executed, and in the multi-value image generation process, the multi-value image is generated based on the character to which the dashed line has been added in the dashed line addition process. If the character shown in the character data detected in the character detection process is a thin character shape, the dashed line addition process is not performed, and a density increase process is performed to increase the density of the character shown in the character data detected in the character detection process, and in the multi-value image generation process, the multi-value image is generated based on the character whose density has been increased by the density increase process. The printer is configured as follows:

10. A printer comprising a printing device and a controller, The controller an acquisition process for acquiring image data; a multi-value image generation process for generating a multi-value image based on the image data acquired in the acquisition process; a binarization process for converting the multi-valued image generated by the multi-valued image generation process into a binary image; a printing process that causes the printing device to perform printing based on the binarized image generated by the binarization process; is executable, The controller further comprises: After the acquisition process is performed and before the multi-valued image generation process is performed, a character detection process for detecting character data indicating characters from the image data acquired in the acquisition process; a dashed line addition process for adding dashed lines to edges of characters shown in the character data detected in the character detection process; Run the dashed line added by the dashed line addition process has a plurality of line portions and non-line portions between the line portions, and when the size of the character indicated in the character data detected by the character detection process is a first size, the ratio of the line portions to the non-line portions is lower than when the size of the character indicated in the character data detected by the character detection process is a second size larger than the first size; The printer is configured as follows:

11. 2. The printer according to claim 1, the dashed line added by the dashed line addition process has a plurality of line portions and non-line portions between the line portions, and when the density of the character indicated in the character data detected by the character detection process is a first density, the ratio of the line portions to the non-line portions is lower than when a second density higher than the first density is used; The printer is configured as follows:

12. 2. The printer according to claim 1, The controller When the density of the character indicated in the character data detected in the character detection process is higher than a first threshold, the dashed line addition process is not performed, and the first threshold is higher than 70%. The printer is configured as follows:

13. 2. The printer according to claim 1, The controller When the density of the character indicated in the character data detected in the character detection process is lower than a second threshold, the dashed line addition process is not performed, and the second threshold is lower than 60%. The printer is configured as follows:

14. 14. The printer according to claim 1, The controller In the character detection process, a text object is detected as the character data from the image data acquired in the acquisition process; the dashed line addition process acquires data indicating the outline shape of each character shown in the text object detected in the character detection process, and generates intermediate data by adding the dashed lines along the outline shapes indicated in the acquired data; In the multi-value image generation process, the multi-value image is generated based on the intermediate data generated in the dashed line addition process. The printer is configured as follows:

15. 15. The printer according to claim 14, The controller In the dashed line addition process, data indicating the outline shape of each character shown in the text object detected in the character detection process is acquired, and the intermediate data is generated by adding the dashed lines inside the edges of the characters along the outline shapes indicated in the acquired data. The printer is configured as follows:

16. 15. The printer according to claim 14, The controller In the dashed line addition process, data indicating the outline shape of each character shown in the text object detected in the character detection process is acquired, and the intermediate data is generated by adding the dashed lines to the outside of the edges of the characters along the outline shapes indicated in the acquired data. The printer is configured as follows:

17. 14. The printer according to claim 1, The controller In the dashed line addition process, the dashed line having a width of 1 dot is added. The printer is configured as follows:

18. 14. The printer according to claim 1, The controller In the dashed line addition process, the dashed line is added with a density of 100%. The printer is configured as follows:

19. 14. The printer according to claim 1, the dashed line added by the dashed line adding process has a plurality of line portions and non-line portions between the line portions, The length of each line segment corresponds to the number of consecutive black dots, The length of each non-linear portion corresponds to the number of consecutive white dots. The printer is configured as follows:

20. 14. The printer according to claim 1, the dashed line added by the dashed line adding process has a plurality of line portions and non-line portions between the line portions, The length of each line segment is proportional to the number of consecutive black dots. The length of each non-linear portion is proportional to the number of consecutive white dots. The printer is configured as follows:

21. A program executable by a computer of an information processing device, the program corresponding to a printer connected to the information processing device, The computer, an acquisition process for acquiring image data; an output process for outputting a print command to cause the printer to print an image based on the image data acquired in the acquisition process; It is possible to execute The computer further comprises: After the acquisition process is executed and before the output process is executed, a character detection process is executed to detect character data indicating characters from the image data acquired in the acquisition process; If the size of the characters indicated in the character data detected in the character detection process is equal to or larger than a predetermined size, a dashed line addition process is executed to add dashed lines to edges of the characters indicated in the character data detected in the character detection process, and in the output process, the print command is output to cause the printer to print the image including the characters to which the dashed lines have been added in the dashed line addition process; If the size of the character indicated in the character data detected in the character detection process is smaller than the predetermined size, the dashed line addition process is not executed. A program that is structured as follows.

22. A program executable by a computer of an information processing device, the program corresponding to a printer connected to the information processing device, The computer, an acquisition process for acquiring image data; an output process for outputting a print command to cause the printer to print an image based on the image data acquired in the acquisition process; It is possible to execute The computer further comprises: After the acquisition process is executed and before the output process is executed, a character detection process for detecting character data indicating characters from the image data acquired in the acquisition process; a dashed line addition process for adding dashed lines to edges of characters shown in the character data detected in the character detection process; Execute the dashed line added by the dashed line addition process has a plurality of line portions and non-line portions between the line portions, and when the character shown in the character data detected by the character detection process has a thin character shape, the ratio of the line portions to the non-line portions is lower than when the character has a non-thin character shape; A program that is structured as follows.

23. A program executable by a computer of an information processing device, the program corresponding to a printer connected to the information processing device, The computer, an acquisition process for acquiring image data; an output process for outputting a print command to cause the printer to print an image based on the image data acquired in the acquisition process; It is possible to execute The computer further comprises: After the acquisition process is executed and before the output process is executed, a character detection process is executed to detect character data indicating characters from the image data acquired in the acquisition process; If the print resolution is equal to or greater than a predetermined resolution, a dashed line addition process is executed to add dashed lines to edges of characters indicated in the character data detected in the character detection process, and in the output process, the print command is output to cause the printer to print the image including the characters to which the dashed lines have been added in the dashed line addition process; If the print resolution is lower than the predetermined resolution, the dashed line addition process is not executed. A program that is structured as follows.

24. A program executable by a computer of an information processing device, the program corresponding to a printer connected to the information processing device, The computer, an acquisition process for acquiring image data; an output process for outputting a print command to cause the printer to print an image based on the image data acquired in the acquisition process; It is possible to execute The computer further comprises: After the acquisition process is executed and before the output process is executed, a character detection process is executed to detect character data indicating characters from the image data acquired in the acquisition process; if the character indicated by the character data detected in the character detection process is not a thin character, a dashed line addition process is executed to add dashed lines to edges of the character indicated by the character data detected in the character detection process, and in the output process, the print command is output to cause the printer to print the image including the character to which the dashed lines have been added in the dashed line addition process; If the character detected in the character data by the character detection process is a thin character, the dashed line addition process is not executed. A program that is structured as follows.

25. A program executable by a computer of an information processing device, the program corresponding to a printer connected to the information processing device, The computer, an acquisition process for acquiring image data; an output process for outputting a print command to cause the printer to print an image based on the image data acquired in the acquisition process; It is possible to execute The computer further comprises: After the acquisition process is executed and before the output process is executed, a character detection process for detecting character data indicating characters from the image data acquired in the acquisition process; a dashed line addition process for adding dashed lines to edges of characters shown in the character data detected in the character detection process; Execute the dashed line added by the dashed line addition process has a plurality of line portions and non-line portions between the line portions, and when the size of the character indicated in the character data detected by the character detection process is a first size, the ratio of the line portions to the non-line portions is lower than when the size of the character indicated in the character data detected by the character detection process is a second size larger than the first size; A program that is structured as follows.

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