JPH03164274A - Printer - Google Patents

Abstract

PURPOSE:To control beam emitting time, and to obtain a print of high resolution without collapse of a character even in the case of a small character print by shortening a pulse width by pulse width control means if a character smaller than at least one character size determined previously is contained in a printing page. CONSTITUTION:A central processor 3 controls a width controller 14 in response to a character size, then instructs a start of printing to a printing mechanism controller 12, controls a printing mechanism 13 by the controller 12, and starts printing. When the printing is started, an image developed to a page memory 8 is converted into a pulse by a parallel/serial converter 9 at each one raster, and sent to the controller 14. The controller 14 controls the pulse width of a '1' level to the already set pulse width, and then sends the pulse to a beam driver 10. The driver 10 turns ON, OFF a beam generator 11. Thus, the pulse width when a small size character is printed by the controller 14 is shortened to improve its resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printing device that forms a printed image by scanning a beam.

BACKGROUND ART A latent image is recorded on a photosensitive drum using a beam generating means such as a laser based on a certain image signal from graphic or character data, and then the image signal is recorded by pressing a button on an electrophotographic printing device that develops the image using toner. Generally, it is formed from a binary signal of "1", which is a signal level for image recording, and "O", a signal level for which image recording is not performed.

An example of such a conventional printing device will be described below.

FIG. 4 is a block diagram of a conventional printing device.

The host computer 2 sends character codes and image data to the printing device 1. The printing device 1 includes a central processing device 3 that controls the entire printing device;
Program ROM that stores the program that operates the
4. character data pROMts storing character data of each size corresponding to the character code; interface section 6 for receiving print data from host computer 2; page memory section 8 for storing image data for one page;
From the input data shifter part 7, which writes data while shifting the font to the page memory part 8, reads out the image data stored in the page memory part 8, and converts it into serial data. a beam driving unit 1o that drives a laser diode according to serial number data; a beam generating unit 11 that generates a certain beam from the laser diode; a printing mechanism unit 13 that performs printing;
There is a printing mechanism control section 13 that controls the printing mechanism section 12 .

The operation of the conventional printing apparatus constructed as described above will be explained with reference to the flowchart shown in FIG. The interface unit 6 receives the print data sent from the host computer 2 (step 2), and the central processing unit 3 determines whether the received data is a character code or image data (step 2). data ro
Reads the character data corresponding to the character code in the currently selected character size from M5 and writes it to the page memory section 8 through the parenoren lid part 7 (Step No.)
. If the received data is image data in step O, the received data is directly written to the page memory section 8 through the 1-panel shifter section 7 (step 2). Steps 1 to 2 are repeated when image creation for one page is completed (step ■). When image creation for one page is completed, central processing unit 3 instructs printing mechanism control section 12 to start printing ( Step O). The instructed printing mechanism control section 12 controls the printing mechanism section 13 to start printing (
Step ■). When printing starts, the image developed in the page memory unit 8 is converted into a parallel image by the parallel serial converter 9 for each raster, and then transferred to the beam driver 10.
According to this pulse, the beam driving section 1o and the beam generating section 11i0N. Turn off. As shown in FIG. 6, the pulses output from the parallel-to-rear converter are at the level /L/(beam lighting) and the "0" level/L.
/ (beam off) Both have the same panorez width.

In this way, all images in the page memory section 8 are output! The step is repeated and printing ends (
Step ■).

Problems to be Solved by the Invention As mentioned above, in conventional printing devices, printing is performed with a constant pulse width regardless of the character size. Disadvantage? had.

The present invention was made in view of the above, and aims to provide a printing device that can obtain good resolution without blurring of characters even when printing small-sized characters.

Means for Solving the Problems The present invention is provided with a control means that shortens the light emission time of the beam when printing characters smaller than at least one predetermined character size.

Function: When a printed page contains at least one character smaller than a predetermined character size, the pulse width control means controls the beam irradiation time by shortening the panorez width to print small characters. It is also possible to provide printing with good resolution without clutter.

Embodiment Hereinafter, one embodiment of the printing device of the invention will be described in detail.

FIG. 1 is a block diagram of the printing device of the Wood invention. 1st
In the figure, the parts given the same numbers as in the brochure diagram of the conventional printing device have the same structure, and therefore the explanation will be omitted.

14 Pulse IW control part A, which lights up the beam within the pulses output from the parallel serial converter 92)> (pulse width of "1" level). Showing T,,T2,T3
It is configured to control the

The operation of the printing apparatus of the invention constructed as described above will be explained according to the flowchart shown in FIG. The interface unit 6 receives the print data sent from the host computer 2 (step ■), and the central processing unit 3 determines whether the received data is a character code or image data (step @), and if it is a character code, it is a character. Data R
The character data corresponding to the character code in the currently selected character size is extracted from the OM5 and transferred to the page memory section 8 through the storage section 7.
). If the received data is image data in step O, the received data is written to the page memory section 8 through the shifter part γ (step @).
. Step 1 completes the image creation for 1 page. Step 1 repeats ~ @ gold. When image creation for one page is completed, the central processing unit 3 determines the minimum character size within the page, and if the minimum character size is 8 points (1 point} = 1772 inches) or less (step 0), the pulse width control unit 14, an instruction signal is output to set the pulse width to T3 (stenop ■). When the minimum character size on the page is above 8 points and below 12 points, the pulse width is set to T2 in the Panores II control unit (step).
An instruction signal is output in order to do so (step ■). When the minimum character size within the page is greater than 12 points, an instruction signal is output to the pulse width control section 14 to set the pulse width to 1 (step 2). After controlling the panorez width control section 14 according to the character size, the central processing unit 3 instructs the printing mechanism control section 12 to start printing (step 2).

The instructed printing mechanism control section 12 controls the printing mechanism section 13 and starts printing (step 2). When printing is started, each image raster developed in the page memory section 8 is converted into a pulse by the parallel serial converter 9 and sent to the pulse width controller 14. Pulse width control section 1
4, the pulse width of the "91" level is controlled to the already set pulse width, and then the pulse is sent to the beam driving section 10, and the beam driving section 10 and the beam generating section 11i0N- are turned off in accordance with this pulse.In this way, the page memory is turned off. At step 1, when all images in the portion 8 have been output, step (2) is repeated and printing is completed (step (2)).

As detailed above, in the printing device of this embodiment, the resolution can be improved by shortening the panorez width when printing small-sized characters using the pulse width control means, and the printing device has excellent printing quality. It is now possible to provide this information and is extremely useful in practice.

Effects of the Invention The present invention has the following advantages:
To provide a printing device with excellent printing quality without smearing of characters even when pressing a button on small-sized characters since the light emission time of a light emitting means during scanning is changed.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the printing device of the present invention, Fig. 2 is an operation flowchart of the printing device of the invention, and Fig. 3 is an example of the timing of displaying an image signal of the printing device of the invention. 4 is a block diagram of a conventional printing device, and FIG. 5 is an operation flowchart of a conventional printing device.
FIG. 6 is a timing chart showing an example of an image signal of a conventional printing device. 1... Printing device, 2... Host computer, 3... CPU, 4... Program ROM, 5... Character data ROM, 6.
...Interface part, 7...Part of barrel lid, 8...Page memory part, 9...
・・・BararenoResiliaNore conversion part, 1o...
Beam driving section, 11... Beam generating section, 12.
. . . Printing mechanism side part, 13 . . . Printing mechanism section, 14 . . . Panorez width control section.

Claims (1)

[Claims] A printing device is provided with a light scanning means for scanning light generated by a light emitting means that generates a beam, and forms a printed image by controlling the light emitting means on and off during scanning, and is capable of controlling the size of characters to be printed. 1. A printing device comprising: an identification means for identifying; and a control means for changing the light emitting time of the light emitting means in accordance with the identification result of the identification means.