JPH04115975A - Image output device - Google Patents

Abstract

PURPOSE:To conduct a correction for reducing steps to improve a printing quality by a method wherein comparing image data is compared with a plurality of predetermined image patterns, an output timing of image data from a temporary storage means is advanced or delayed by a specified time, and a plurality of shift data signals shifted from each other by the specified time are generated. CONSTITUTION:Comparing image data is transmitted to a logic circuit 18 as required and compared with predetermined patterns. Shift data is transmitted to flip flops 19-22 to be shifted by 2 VCLK cycles. In this manner, 3 types of output timings are obtained. Respective shift data signals shifted from each other and coincidence signals SEL1 and SEL2 representing a comparison result from the logic circuit part are both transmitted to three input NANDs 23-25 to select a shift data signal. Using the shift data signal as an output timing, image data is outputted as a VIDEO signal. In this manner, dot positions can be shifted, and a step produced at the time of an oblique line printing or the like can be corrected.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a laser printer, etc. that outputs images such as characters and symbols by horizontally and vertically scanning image data constituting an orthogonal matrix in the row and column directions. This invention relates to improving image quality in an image output device.

(Prior Art) A block diagram of the hardware of a conventional laser beam printer is shown in FIG. In the 8th rXJ, 27 is an image storage means for storing image data that can be read out at any time, and 28 is an image storage means that converts the image data sent in parallel from the image storage means 27 into 7real and outputs it as a V I DEO output. 29 is an output means for outputting the V I DEO output signal as an image to a photosensitive drum or the like.

The operation will be explained below.

In the conventional printing apparatus shown in the block diagram shown in FIG. 8, image data sent in parallel from an image storage means 27 (generally a DRAM) is converted into a real image by a parallel-to-real conversion means 28 (generally a 7-foot register). Because it was being output as a V I DEO data signal,
The output timing of horizontal scanning of image data was constant.

(Problem to be solved by the invention) When printing diagonal lines etc. in the conventional configuration as described above8
The resulting printing result is as shown in section 9 a1, and there are problems such as clearly visible steps at the joints between straight lines, resulting in deterioration of the overall printing quality. there were.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image output device that solves these problems and improves print quality by correcting steps to reduce them.

(Means for Solving the Problems) In order to solve the problems, the present invention provides an image storage means for storing image images such as characters and symbols in the form of image data in an orthogonal matrix in the row direction and column direction. , temporary storage means for generating a plurality of comparison image data by incorporating data before and after the image data held in the image storage means in a predetermined pattern into the output data of the image data and temporarily storing the data; The comparison image data inputted from the temporary storage means is compared with a plurality of predetermined image patterns, and if it matches one of the image patterns, outputs a matching signal according to the type of the image pattern. a comparing means; a shifting means that advances or delays the output timing of the image data from the temporary storage means by a prescribed time to generate a plurality of 7-foot data signals that are shifted from each other by a prescribed time; and from the comparing means. and a plurality of shift data signals from the shift means, and selects a shift data signal according to the type of the match signal from the comparison means, and outputs the selected shift data signal as a video output timing signal. This image output device is characterized in that the output position of the image data can be changed by making the output timing variable when outputting the image data.

(Function) In the present invention, a plurality of comparison image data are generated by rearranging the image data to be output called from the image storage means in the temporary storage means with the image data before and after it according to a predetermined pattern (rule). Next, the plurality of comparison image data are converted into image butter/image data set in advance within the comparing means.
If there is a match, a match signal corresponding to the type (usually three types) of the image pattern is output.

In response to the same coincidence signal, the shift means generates a shift data signal with a different output timing, and outputs it as the output timing signal of the image data to be output.By changing the output timing of the image data, When printing, the position of the dots at the joints between straight lines is changed,
By making the difference in level at the seam less noticeable, it is possible to improve the overall printing quality.

(Example) An example of the present invention will be described below. A block diagram of the present invention is shown in FIG.

In FIG. 1, l is an image storage means that can be read at any time and stores image data, and 2 is a storage means for storing image data stored in the image storage means l according to a predetermined rule. Temporary storage means for generating comparison image data by rearranging the image data and temporarily retaining them; 3 has a plurality of predetermined image patterns; 4 is a comparison means for outputting a matching signal according to the type of the image pattern when the image data matches at least one of the image patterns; 4 is the output timing of the image data from the temporary storage means 2; Shifting means for shifting a plurality of shift data signals by a predetermined time and producing a plurality of shift data signals mutually shifted by a predetermined time; 5 receives a coincidence signal from the comparison means 3 and a plurality of shift data signals from the shift means; and signal selection means for selecting a shift data signal depending on the type of the matching signal from the comparison means.

The operation will be explained below.

FIG. 2 is a detailed circuit diagram of the image storage means 1 and the temporary storage means 2.

In FIG. 2, the image storage means 1 is a DRAM 7, and the temporary storage means 2 is a high-speed SRAM 6, which converts the data sent in parallel from the DRAM 7 into real data.
bit/ft register 9, 8bit from the SRAM 6
The 8bit serial data sent from the 8bit/ft register 9 is added to the t data and returned to the SRAM 6 again.
t data register register 8, an 8-bit data register 8 that performs 7real-to-halal conversion to create comparison image data to be sent to the comparison means 3 and shift image data to be sent to the shift means 4 from the data sent from the 8-bit data register 8 to the SRAM 6; It is composed of shift registers 10 to 17.

FIG. 3 is a detailed circuit diagram of the comparison means 3, the shift means 4, and the signal selection means 5.

In FIG. 3, the 8b1t/ft register 10 to 1
Logic circuit 18 configured with NAND and OR gates that receives comparison image data from 7 and outputs a match signal when it matches at least one of a plurality of predetermined image patterns;
Shifting means 4 receives shift data signals from 0 to 17 and generates three types of signals: a shift data signal shifted by 2 cycles and 4 cycles of VCLK, and a shift data signal without shift. The flip-flops 19 to 22 of the flip-flops receive three types of shifted data signals from the flip-flops 19 to 22, select one of the three types based on the control signal from the logic circuit section 18, and output the VIDEO signal.
These are the three-man power NAND 23 to 25 and the three-man power 0R26, which are the signal selection means 5 to output as a signal.

Here, as shown in Fig. 4, the data a = h is held in advance in the SRAM 6 (Fig. 4 a), and the DRAM
If image data (Di to D8) is sent from 7 (
4b), the image data (DI to D8) are serially converted by the shift register 9 (FIG. 4C). This serially converted data is data a from SRAM6.
It is sent to the data register 8 together with Nh, the data of h is discarded, the data of a to f are shifted one bit at a time, and Dl is added to the position where the data of a was located (Fig. 4d).
The aNh data in the RAM 6 is stored at the location where it was held. By repeating this series of actions 8 times, SRA
D1 to D8 are stored in the row where the data of a in M6 was located.

At the same time as the data shown in FIG. 4d is stored in the SRAM 6, this 8-bit data is also stored bit by bit in the 8-bit shift registers 10 to 17 (FIG. 4e).
) This creates comparison image data and shift data in which the lowest bit is updated to the latest data (FIG. 4f). This means that if the data to be output changes, the comparison image data around it also changes accordingly.

The comparison image data is sent to the logic circuit 18 as needed and compared with a predetermined pattern. Here, as an example of the logic circuit section 18, in the case shown in FIG. 5a, if you want to print the H dot later than usual as shown in FIG. 5, you can print it as shown in FIG. Logic circuit section 1
This is realized by configuring within 8.

The shift data is sent to flip-flops 19 to 22, and shifted by two cycles of VCLK. As a result, three types of output timings as shown in Fig. 6a, b, and c are obtained, and the output timing when no correction is
To illustrate, if you want to advance the output timing, you can achieve this by outputting the image data at the timing shown in FIG. 6A, and if you want to delay the output timing, you can achieve this by outputting the image data at the timing shown in FIG. 6C.

Coincidence signals 5ELL and 5E indicating the comparison results from the logic circuit section and the data signals for each /ft which were each shifted by 7
L2 will be sent to the 3rd NAND 23-25, the 7th
A shift data signal is selected according to the pattern shown in the figure, and the image data is outputted as a VIDEO signal using this as the output timing. As a result, it is possible to shift the position of the pattern number shown in FIG. 7, and it is possible to correct differences in level that appear during printing, such as diagonal lines. In this way, the output image before correction (Figure 9a) is converted to the output image after correction (Fig. 9a).
It is changed as shown in Fig. 9b).

(Effects of the Invention) As described above, according to the present invention, by having the image storage means, temporary storage means, comparison means, shift means, and signal selection means, it is possible to shift the output position of image data from the normal position. This makes it possible to correct differences in seam height that appear during printing, such as diagonal lines, and improve the overall printing quality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a detailed circuit diagram of the image storage means and temporary storage means of the same embodiment, and FIG. 3 is a comparison means, shift means, and signal of the same embodiment. A detailed circuit diagram of the selection means, FIG. 4 is an explanatory diagram showing the rough flow of data in the same embodiment, and FIG. 5 shows an image of how the level difference is corrected in the same embodiment and an example of the comparison means at that time. 6 is a timing diagram showing each output timing, and FIG. 7 is a 5ELL, 5 when each output timing is selected.
An explanatory diagram showing the EL2 signal and the state of printed dots in each case, Fig. 8 is a block diagram of a conventional image output device, and Fig. 9 is an image of printing by the conventional device and an image of printing by the present invention. FIG. Image storage means Temporary storage means Comparison means Shifting means Signal selection means Patent application Person Matsushita Electric Industrial Co., Ltd. Agent

Claims (1)

[Claims] (1) Image storage means for storing image images such as characters and symbols in the form of image data in an orthogonal matrix configuration in the row and column directions, and data output from the image data held in the image storage means Incorporate the data before and after that in a predetermined pattern to generate multiple image data for comparison,
If the comparison image data inputted from the temporary storage means and a plurality of predetermined image patterns are compared with a temporary storage means for temporarily storing them, and the comparison image data matches one of the image patterns; a comparison means for outputting a matching signal according to the type of the image pattern, and a plurality of shift data that are shifted by a prescribed time from each other by advancing or delaying the output timing of the image data from the temporary storage means by a prescribed time. a shift means for generating a signal, receiving a coincidence signal from the comparison means and a plurality of shift data signals from the shift means, and selecting a shift data signal according to the type of the coincidence signal from the comparison means; and signal selection means for outputting as a video output timing signal,
An image output device characterized by changing the output position of image data by making output timing variable when outputting image data.