JPS62164547A - Printer - Google Patents

Abstract

PURPOSE:To enable a superimposed character to be easily read, by a system wherein dot pattern information on each character and attribute information on each character are stored in a font memory, a logical operation is conducted on the character dot pattern information and the corresponding dots in an image memory according to the content of the attribute information, and the result of the logical operation is stored into the image memory. CONSTITUTION:Dot pattern information on each character and attribute information on each character are stored in a font memory 401, and an ALU 402 is provided between the font memory 401 and in image memory 103. When transferring the dot pattern information on a predetermined character from the font memory 401 to the image memory 103, the ALU 402 performs a logical operation according to the content of attribute bits corresponding to the character, and stores the result of the logical operation back into the image memory 103. Accordingly, when a plurality of images such as a character and a character or a character and halftone dots, a figure or the like are printed in a superimposed form, the superimposed parts can be printed clearly, and the superimposed character can be easily read.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a plurality of characters, or characters and
Regarding a printing device capable of printing various images such as figures by superimposing them, in particular, clarifying the above-mentioned superimposed part,
The present invention relates to a printing device that allows superimposed characters to be easily read.

[Prior art] Image information to be printed is placed in dots (pixels)
Executes two-in-one image processing and converts it into a digital signal.
2. Description of the Related Art Printing devices that print image information on a predetermined sheet of paper are already known.

FIG. 6 shows a conventional example of an information processing section in such a printing apparatus.

In FIG. 6, a host computer or other host device i!
Input data such as character codes inputted from the i (not shown) through the input signal line 106 are sent to the page memo IJI.
OL, and at least one page's worth of human data is stored therein. The input data corresponding to the character code etc. read from the page memory 101 is stored in the font memory 101.
2 as its address data.

In the font memory 102, dot pattern information for all types of characters that may be printed is stored at addresses corresponding to each character code in a ROM or RAM. Therefore, based on the address corresponding to a specific character code read from page memory 101, character dot pattern information corresponding to this character code is output from font memory 102.

The character dot pattern information read from the font memory 102 is supplied to the image memory 103 and stored at an address corresponding to the arrangement of the dots when printed on paper. For this purpose, the image memory 103 is a so-called full bitmap memory, which corresponds to all the dots on one page, for example.

The dot pattern data output from the image memory 103 is supplied to the printing unit 104, and based on this dot pattern, a recording material (not shown) is printed mechanically or electrically.
recorded in

For example, when a laser beam printer is used as the printing unit 104, the dot pattern data read from the image memory 103 is converted into a serial signal, and the laser beam scanning the photoconductor is optically modulated according to this serial signal. , recorded on the recording material. As a result, for example, black and white image information is reproduced on the recording material.

The control unit 105 obtains various control signals that control the operation of the entire printing apparatus.

That is, the page memory 101. Font memory 102
, a desired address signal and a read or write signal are sent to the image memory 103, and when all the dot patterns for one page are stored in the image memory 103, a command is sent to the printing unit 104 to start printing. A command signal is output.

The timing of these control operations is controlled based on a control program stored in a microcomputer within the control unit 105, but this is not related to the present invention.
A detailed explanation thereof will be omitted.

FIG. 7 shows the font memory 102 and the image memory 10.
3 is a diagram showing the relationship with 3.

In the font memory 102, for example, a dot pattern of the character rA4 as shown in FIG. 7(a) is stored in an area starting from an address corresponding to a single character code as shown in the figure.

This dot pattern for one character is stored in image memory 10.
3, that is, as shown in FIG. 7(b),
It is transferred to the address corresponding to the position on the paper to be printed. At this time, if other data is stored in advance at the same address in the image memory 103, the data stored in I2f and the data to be stored elsewhere can be ORed.
) and then stored again at the same address.

As a result, overlapping printing of characters and characters, characters and figures, etc. is realized.

However, in the case of such a conventional printing apparatus, since superimposed data is obtained by a simple OR output, there is a problem that depending on the data to be superimposed, one overlapping part is extremely difficult to see.

For example, as shown in FIG. 8, when normal characters 107 are superimposed on a background 10B with a high density such as a solid ring or a dot, the characters 107 are hidden behind the background 106 and cannot be read. There is a problem.

Since normal characters are patterns with relatively thin lines, there is a problem in that even the presence of some halftone dots in the background makes the printing extremely difficult to read.

[Object of the Invention] The present invention has been made by focusing on the above-mentioned problems of the conventional art. It is an object of the present invention to provide printing 'fa a' that makes the overlapping part clear and allows the overlapping characters to be easily read.

[Embodiments of the invention] FIG. 1 is a block diagram showing one embodiment of the present invention.

In addition, the same reference numerals as in the case of FIG. 6 are given to the members having the same Jl i@ as in the conventional example of FIG. That is, in FIG. 1, a page memory lot, an image memory 103, a printing section 104, a control section 105. Input signal line 1
06 has the same configuration and functions as the case in FIG.

The features of the present invention are that dot pattern information of each character and attribute information provided for each character are stored in the font memory 401, and that an ALU ( logic operation section) 402
The point is that

FIG. 2 is a diagram showing an example of the contents of the font memory.

The font memory 401 is composed of a one-character pattern section 41 and an attribute section 42.

The character pattern section 41 is a part that stores the dots and dots and dots of each character, similar to a conventional font memory. The a-character part 42 is a part that stores, for each character, an attribute bit (attribute information) indicating an attribute required when printing that character. This attribute bit consists of, for example, two bits.

FIG. 3 is a block diagram showing a specific example of the ALU used in the above embodiment.

This ALU 402 is a circuit that performs a logical operation according to the contents of attribute bits corresponding to the character when transferring dot pattern information of a predetermined character from the font memory 401 to the image memory 103. The result of this logical operation is then stored in the image memory 103 again.

ALU 402 includes a font data register 501, a mode register 502, an image memory data register 503, and an arithmetic circuit 504.

First, the font data register 501 latches dot pattern information (for example, 8 bits) of a predetermined character, and the font data register 501 latches the attribute bits (for example, 2 bits) corresponding to the character for the latched information.
bit) is latched by mode register 502.

Next, the image memory data stored in the image memory 103 is read out from the address position where character dot pattern information is about to be written, and the read data is transferred to the image memory data register. Latch to 503.

Then, depending on the contents of the attribute bits latched in the mode register 502, the dot pattern information latched in the font data register 501 and the image memory data latched in the image memory data register 503 (each (between corresponding bits), various logical operations are performed.

FIG. 4 is a chart showing an example of the contents of the attribute bee/ ) in the above embodiment.

As shown in FIG. 4, when the attribute bit is "00", data obtained by ORing the dot pattern information of each character and the image memory data is output from the ALU 402, and the attribute bit is "Ol". In this case, the ALU 402 outputs data obtained by ANDing the dot pattern information of each character and the image memory data.

In addition, when the attribute bit is "10", the dot pattern information of each character and the image memory data are exclusive
If the data with R is output from the ALU 402 and the attribute bit is "11", the dot pattern information of each character is output from the ALU 402 as is.

Next, taking one character rAJ as an example, the font memory 401
The operation of writing data to the image memory 103 via the ALU 402 will be described.

Here, the operation when writing the character "rA" shown in FIG. 7 (IL) from the font memory 401 to the image memory 103 via the ALU 402 will be described.

If "lO" is specified as the attribute bit corresponding to the character rAJ, the exclusive OR mode is executed as shown in FIG. In this case, when printing the letters rAJ on a normal white background, only the dots that are desired to be black are printed in black, as in the past. At this time, if a moat background such as a solid black background is written in the image memory 103, the characters rAJ are written in white on the solid black background.
is printed, and the letters rAJ are printed in black on a white background. This state is shown in FIG.

If printed in this way, there will be no problem of the characters being hidden in the background and becoming invisible and illegible.

Furthermore, even if one character is printed overlapping another, there is no problem of erroneously reading five characters.

Note that if a rewritable fm memory element is used as the font memory 401, attribute bits can be freely selected depending on the background of the characters to be printed or the character type (size, thickness, font, etc.). can.

In the above embodiment, two bits are assigned to each character stroke as attribute bits, but the attribute bit is not limited to bit a, and one bit or three or more bits may be assigned to select various modes.

Furthermore, in the above embodiment, only black and white binary images were handled, but in an apparatus having a printing section capable of black and white multi-value printing (black and white printing with a gradation) or color printing, it is possible to , 67&, or a color may be selected.

[Effects of the Invention] According to the present invention, when a plurality of characters or characters and various images such as halftone dots and figures are printed in an overlapping manner, the overlapping portion can be made clear. ,
This has the effect that superimposed characters can be easily read.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing an example of the contents of the font memory used in the above embodiment. FIG. 3 is a block diagram showing a specific example of the ALU used in the above embodiment. FIG. 4 is a chart showing an example of the contents of attribute bits in the above embodiment. FIG. 5 is a diagram showing an example of printing in the above embodiment. FIG. 6 is a block diagram showing an example of the main parts of each conventional printing unit. FIG. 7 is a diagram showing the relationship between the font memory and the image memory in the conventional device. FIG. 8 is a diagram showing an example of printing characters on a black background when using the conventional apparatus described above. 101... Page memory, 10.3... Image memory, 104... Printing section, 401... Font memory, 402... ALU. Patent applicant Canon Co., Ltd. Figure 4/j
. Figure 6 Figure 7

Claims (1)

[Scope of Claims] A printing device comprising an image memory that stores character dot pattern information read from a font memory as image memory data, and a printing unit that prints on paper based on the image memory data, Dot pattern information for each character and attribute information provided for each character are stored in the font memory, and the character dot pattern information and the corresponding dots in the image memory are stored in accordance with the content of the attribute information. A printing apparatus characterized in that the printing apparatus performs a logical operation on the image memory and stores the result of the logical operation on the image memory.