JPH04332668A - Printer - Google Patents

Abstract

PURPOSE:To obtain a character of a clear profile to print an overlaied image with a high character quality. CONSTITUTION:A font memory 3 prestores image data of different densities. Document information containing image data and character information is inputted through a host computer I/F 2 and stored in a page memory 7. A CPU 9 determines at least a density of a boundary part of an image and a character on the basis of the stored document information. A printer engine 13 prints the boundary part in accordance with the determined density at the time of printing.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus, and more particularly, to a printing apparatus that simultaneously prints high-density images and characters.

0002

[Prior Art] Conventionally, when overlaying an image and text on the same page, dot data (hereinafter referred to as "image data") created by the image is overlaid with dot data (hereinafter referred to as "text") created by the image. data) were simply superimposed on each other.

0003

[Problems to be Solved by the Invention] However, in the above conventional example, when overlaying high-density image data (multivalued data) with character data (binary data), the outline of the character becomes unclear and the character The problem was that the images were printed out blurry.

The present invention has been made in view of the above-mentioned drawbacks of the conventional examples, and its purpose is to provide a printing device that can clearly print characters even if the characters are overlaid on an image. .

[0005]

[Means for solving the problem] Solving the above problems,
In order to achieve the object, a printing device according to the present invention is a printing device that overlays an image on a character image, and includes a storage means for storing image data of different densities in advance, and image data and character information. an input means for inputting document information; a determining means for determining the density of at least a boundary portion between an image and a character based on the document information input by the input means; and a density determined by the determining means for the boundary portion during printing. and printing means for printing according to.

[0006]

[Operation] According to this configuration, the storage means stores image data of different densities in advance, the input means inputs document information including image data and character information, and the determination means inputs document information input by the input means. Based on this, the density of at least the boundary portion between the image and the character is determined, and the printing means prints the boundary portion at the time of printing in accordance with the density determined by the determining means.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of a printing apparatus according to the present invention. In the figure, 1 is document information and includes image data. Reference numeral 2 indicates a host computer interface (I/F) that exchanges data with a host computer (not shown), and 3 indicates a font memory that generates dot data from character codes included in input document information. 4 and 5 indicate image data tables, respectively. The image data table 4 is a memory in which image data of a normal pixel size is stored in advance, and the image data table 5 is a memory in which image data including a boundary line that divides the pixel size of an image into two is stored in advance.

[0009] Here, dividing the pixel size into two will be explained. The boundary between a character and an image can be of various types, such as a curved line or a straight line, depending on the outline of the character. Storing all examples of boundary lines that arbitrarily divide the pixel size into two in an image memory increases the memory capacity, which is not preferable. Therefore, image data of representative dividing boundaries is stored in memory so that the approximation can be made to some extent. Reference numeral 6 denotes an operation panel, which includes switches for reset, test, discharge, etc., and a display section for displaying simple information such as the current status and errors. 7 indicates a page memory that stores document information input from the host computer I/F 2 in page units; 8 indicates the page memory 7 and image data 4;
5 shows a dot pattern development unit that develops a dot pattern based on the document information stored in 5. Reference numeral 9 indicates a CPU that controls the operation of the entire device, and 10 indicates a CPU which will be described later.
A ROM is shown in which programs, etc. according to the flowcharts shown in (a) and (b) are stored, and 11 is a RAM used as a work area for various programs.

Reference numeral 12 indicates a printer engine I/F which is an interface with a printer engine 13 which will be described later.
Reference numeral 3 indicates a printer engine that performs an actual printing operation according to the dot pattern data developed in the dot pattern development section 8, and 14 indicates internal data, address signals, and
A bus line for transmitting control signals is shown.

Next, the overlay of this embodiment will be explained.

FIG. 2 is a diagram showing an overlay state of images and characters according to this embodiment, and FIG. 3 is a diagram illustrating each pixel size of images and characters according to this embodiment.

In FIG. 2, the broken line divisions indicate the size of one pixel of the dot-patterned character, and the solid line divisions indicate the size of one pixel of the image. As an overlay state between the image and the text, the shaded area has a density of d.
The area of image dot pattern data (image data) having the number 1 is shown, and the white part shows the area of character dot pattern data (character data).

■, ■, ■, ■ shown in FIG. 3 are examples in which one pixel of character data in FIG. 2 is expressed by one pixel of image data. In addition, FIG. 3 shows 1 of the image data.
Pixels, for example, ■ character data corresponding to pixels 1 to 16
It is shown by pixels allocated with numbers up to . That is, it shows that the character data is composed of pixels of 1/16 the size of the image data.

Next, the operation of this embodiment will be explained.

FIGS. 4 and 5 are flowcharts for explaining the printing operation by the CPU 9 of this embodiment, and FIG. 6 is a diagram for explaining the overlay processing of this embodiment.

First, it is assumed that document information 1 including images and characters sent from a host computer (not shown) is stored in page memory 7 via host computer I/F 2. Therefore, it is checked from the document information 1 in the page memory 7 whether there is an overlay between an image and a character (step S1).

[0018] How to check the overlay between this image and text will be explained.

Text information sent from the host computer is stored in the page memory via the host computer I/F. At this point, it can be determined whether image and character data are mixed at the same address in the page memory. The judgment is made by the CPU, which is the main controller of the printer, and the ROM, which controls the printer.
It is. In the above-mentioned mixed portion, character data (binary data) is given priority over image data (multi-value data). In other words, the mixed portion is treated as character data.

[0020] As a result of step S1, if there is no overlay (step S2), the process moves to step S7. On the other hand, if overlay is present in step S2, the density d1 of the image data to be overlaid is checked in the next step S3. This concentration d1 (see Figure 2)
is multi-valued data representing an intermediate tone between the white level and the black level. Here, k is a threshold value set in advance for comparison with the density d1, and this is defined as a value representing the number of halftones. Also, this threshold value k is 6 bits (64 gradations)
000000 (white) to 111111 (black) that can be expressed as
be the range that can be taken. Note that the threshold value k is stored in the image data table 5.

After step S3, the density d1 is compared with a threshold value k (step S4). As a result, the concentration d1
If is smaller than the threshold value k, the characters can be printed clearly due to the overlay because the density of the background image is low, so no special processing is required at the boundary between the image and the characters, and the process moves to step S7. . On the other hand, the concentration d1
If is equal to or greater than the threshold value k, the process of this embodiment is applied to the boundary between the image and the character to clarify the outline of the character, and the process proceeds to the next step S4. In step S4, using the example of FIG. 2, the page memory 7 performs processing as shown in FIG. That is, as the boundary information between the image and the characters, d from the image data table 5 shown in FIG.
Density data d1' including the density represented by 2 (d2<d1) (the diagonal border) is selected (step S5).

This density selection depends on the density of the image, and if the density of the image is low, the boundary between the image and the characters will be clear, so the operation of this embodiment is controlled not to be performed. . In other words, the character (2
(value) data and image (multi-value) data are directly overlaid, and the data is developed in the dot pattern development section 8 of FIG. Furthermore, when the density of the image is high and close to black data (binary black), the boundary between the image and the text (limited to black text) becomes difficult to see, so the operation of this embodiment is effective.

Next, image data of density d2 is assigned to the boundary portion at the time of overlay (step S
6). This allocation is shown in page memory 7 in FIG.
This is done when the data stored in the dot pattern developing section 8 is developed. This control is performed by CPU9 and ROM10.
It is carried out by.

When this allocation is completed, the boundary and background image data and the character data converted into dot data in the font memory 3 are developed in the dot pattern development section 8 (step S7). The dot pattern data developed in the dot pattern development section 8 is output to the printer engine 13 via the printer engine I/F 12 (step S8), and it is determined whether the print quality of the portion to be overlaid by printing is appropriate. That is, it is determined whether the outline of the character is clear or not. Note that this judgment is made by the operator (step S9).

As a result, if the print quality is determined to be appropriate, this process ends; if the print quality is determined to be inappropriate, the process ends.
In order to reduce the density of the image at the boundary, the operator sets one threshold value k (step S10).

The processing from step S4 onwards is executed again.

As explained above, according to this embodiment,
When a high-density image and character data overlay, the outline of the character can be improved by assigning an image with a lighter density to the boundary between the character and the image instead of the part where the outline of the character becomes unclear. This makes it possible to obtain an overlaid printed image with high character quality. In other words, when a nearly black image and a black character are overlapped, the character becomes difficult to see, so by surrounding the outline of the character with a thin image, the outline of the character can be made clear.

Here, the proper use of the image data tables 4 and 5 will be explained.

The use of the image data tables 4 and 5 is determined by the relationship between the image density d1 and the threshold value k. That is, (1) if d1≧k, image data table 5 is used.

(2) If d1<k, use image data table 4.

Furthermore, memory can be saved by making it possible to rewrite the image data including the aforementioned character outlines each time depending on the attributes of the character to be printed (character size, character thickness, etc.). .

Furthermore, by preferentially storing images corresponding to frequently used characters in the image data table 5, the processing speed of the printer controller can be improved.

In the above-described embodiment, the pixel size of the characters relative to the image was set to 1/16, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. be.

[0034]

[Effects of the Invention] As explained above, according to the present invention,
The outline of the characters becomes clearer, and an overlaid printed image with high character quality can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a printing apparatus of the present invention.

FIG. 2 is a diagram showing an overlay state of images and characters according to the present embodiment.

FIG. 3 is a diagram illustrating each pixel size of an image and a character in this embodiment.

FIG. 4 is a flowchart illustrating a printing operation by the CPU 9 of this embodiment.

FIG. 5 is a flowchart illustrating a printing operation by the CPU 9 of this embodiment.

FIG. 6 is a diagram illustrating overlay processing in this embodiment.

[Explanation of symbols]

1 Character information 2　Host computer I/F 3 Font memory 4, 5 Image data table 6 Operation panel 7 Page memory 8. Dot pattern development section 9 CPU 10 ROM 11 RAM 12 Printer engine I/F 13 Printer engine 14 Bus line

Claims (4)

[Claims] 1. A printing device that performs overlay processing of an image on a character image, comprising: storage means for storing image data of different densities in advance; input means for inputting document information including image data and character information; determining means for determining the density of at least a boundary portion between an image and a character based on the document information input by the input means; and a printing means for printing the boundary portion in accordance with the density determined by the determining means during printing. A printing device comprising: 2. The printing apparatus according to claim 1, wherein the determining means also determines the density of the image based on the determined density. 3. The image forming apparatus further comprises a storage means for storing in advance image data of a predetermined size and different densities, and the determining means includes a determining means for determining whether or not the density of the boundary portion can be changed based on the image data. 2. The printing apparatus according to claim 1, wherein if the determination means allows the change, one image data is selected from among the image data stored in the storage means. 4. The printing apparatus according to claim 1, further comprising changing means for changing the density of the boundary portion when printed by the printing means.