JPH02277656A - Image processor - Google Patents

Abstract

PURPOSE:To obtain a printing image which is excellent in image quality by removing lacking of a dot on a border part of a divided image data by a method wherein when a last image data exists on a memory means, dots on the boarder part of an image data former than said data and the received image data are combined, and data processing in which a plurality of dots are taken as a unit is performed. CONSTITUTION:A CPU 2 block receives a sent image data 2 to be stored in a work memory 10. Then, whether a last image data 1 exists in the work memory 10 or not is judged. When the image data 1 exists, data processing in which a plurality of dots are taken as a unit is performed for the image data 1, and the data is expanded on a bit map memory 6. The CPU 2, when a final line of the image data comes, combines dots of the final line of the image data 1 and of a top line of an image data 2, performs data processing in which a plurality of dots are taken as a unit, and expands the data on the bit map memory 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image processing apparatus such as a laser beam printer.

[Conventional technology]

2. Description of the Related Art Conventionally, image processing apparatuses such as laser beam printers are known that print characters and figures expressed in a dot matrix on recording paper. In this image processing device,
The image signal sent from a workstation, etc. is processed to be enlarged or reduced to match the print size.
It is expanded onto bitmap memory. However, images of characters and figures to be printed tend to deteriorate due to processing such as enlargement or reduction, and data processing (interpolation) is required to improve printing quality.

As a conventionally used interpolation method, there is a distance inverse proportionality method using a plurality of dots as a unit. A diagram of the principle of the distance inverse proportionality method is shown in FIG. In this method, first, the point of the original figure corresponding to each point of the processed figure used for enlargement and reduction is checked, and the distance M r from this point P to the surrounding points PO to P3 is calculated.
Find O~r3.

Then, using the reciprocals of these as weights, the brightnesses of points PO to P3 are added together to obtain the brightness of point P, which is then binarized and used as one point of the processing figure.

By the way, image data created and edited on a workstation or the like is sent divided into a plurality of blocks. FIG. 6 shows an example of the image sent. As shown in the figure, the upper data ■ is sent first, and then the lower data ■ is sent. Here, the boundary A between data ■ and data ■
If you look at the enlarged image, you will see that the dots of the sent data (2) are separated by the block boundaries, so the dots on line a in the figure are not sent. At this time, for example, if we look at the four dots in the area surrounded by the rectangle, the lower half of the dots will be missing, making it impossible to perform data processing using the interpolation method described above.

Conventionally, the missing dots have been compensated for by using the data from the front row as is or by treating the line a as white.

[Problem to be solved by the invention]

However, if the previous data is used as is, there is no problem with vertical or horizontal lines, but with diagonal lines, there will be a step, resulting in distortion at the boundary. Furthermore, if the portion of line a is treated as white, white sushi will be formed at the border.

In any case, the conventional method has the problem that the border becomes unsightly, leading to a reduction in image quality.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image processing device that prevents missing dots at the boundaries of divided image data.

[Means to solve the problem]

In order to solve the above problems, an image processing apparatus according to the present invention includes a storage means, such as a work memory, which stores image data sent divided into a plurality of blocks, and a storage means, such as a work memory, which stores received image data once in the In addition to storing the received image data in the storage means, it is determined whether the previous image data exists on the storage means, and if the previous image data exists, the received image data and the previous image data are stored in the storage means. The image data control means combines the dots at the boundary with the image data and performs data processing in units of a plurality of dots.

[Effect]

According to the image data control means, the received image data is temporarily stored in the storage means, and when the next image data is received, data processing is performed on the previous image data in units of multiple dots. When this data processing reaches the final line, the first line data of the next data is taken in, and data processing is performed by combining the dots of the final line and the dots of the first line. As a result, the last line of the previous image data is compensated for by the dots of the first line of the next image data, and image distortion and smearing at the boundary are prevented.

〔Example〕

An example in which the image processing apparatus according to the present invention is applied to a laser beam printer will be described below.

FIG. 2 is a block diagram showing an outline of a laser beam printer. This apparatus is comprised of an image supply device 21, a recording section 22, a power source 23 for driving these, and a panel 24 through which an operator manually issues recording operation instructions.

The image supply device 21 includes a host interface (1/F) connection terminal 26 that receives a signal for recording a predetermined image from a host computer, etc., and a LAN connection that connects it to a LAN (local area network) or the like. A terminal 27 is provided.

The recording unit 22 is a device that records an image corresponding to an image signal on a recording paper 29, and receives an image signal 31 and an operation command 34 from the image supply device 21, and also receives a synchronization pulse 32 for recording operation. and the status signal 33 from the image supply device 2
It is configured to output toward 1.

FIG. 3 is a perspective view of essential parts showing an example of the recording section 22 in FIG. 2. FIG.

In FIG. 3, a laser beam 42 emitted from a laser oscillator 4.1 passes through a polarizer 43, a laser beam modulator 44, and a polarizer 45, and then passes through a polygon mirror 4.
6 and reaches the outer periphery of the photosensitive drum 48 via the lens 47. Image signal 31 from image supply device 21 in FIG.
(bit stream) is inputted to the laser beam modulator 44 from the terminal 51, and the polarization plane of the laser beam passing through the modulator 44 is rotated according to the image signal by, for example, an electro-optic effect. By such an electric shutter action, a black and white binary image signal is converted into an optical on/off signal of a laser beam, and the outer peripheral surface of the photosensitive drum 48 is irradiated with the optical on/off signal. The polygon mirror 46 is rotated at a constant speed by a motor 52, and after reflecting the laser beam, it scans in the direction of an arrow 53 (this direction is referred to as the main scanning direction). That is, while the image signal for one line is converted into an optical bit string and irradiated in a direction parallel to the rotation axis 54 of the photosensitive drum 48, the photosensitive drum 48 is moved in the direction of the arrow 55 (this direction is referred to as the sub-scanning direction). Rotate. In this way, an electrostatic latent image corresponding to the image to be recorded is formed on the photosensitive drum 4.
It is formed on the outer peripheral surface of 8.

This electrostatic latent image passes through a developing device 56 as the photosensitive drum 48 rotates in the direction of an arrow 55. Here, toner is deposited in accordance with the electrostatic latent image. When the recording paper 29 is fed in the direction of arrow 58 by a recording paper transport mechanism (not shown), the toner attached to the outer periphery of the photosensitive drum 48 is transferred onto the recording paper 29 by the action of the transfer device 59. The recording paper 29 is further fed in the direction of the arrow 58 and subjected to processing such as fixing, thereby obtaining a recorded matter. Note that the laser beam 42 is scanned in the direction of an arrow 53 with a width exceeding both ends of the photosensitive drum 48 . Therefore, the transfer timing of the image signal 31 is determined by detection pulses that detect the passage of the laser beam from the scan start sensor 61 and the scan end sensor 62.

FIG. 1 is a block diagram showing a specific circuit configuration of the image supply device 21 in FIG. 2. As shown in FIG. This circuit consists of a microprocessor (hereinafter referred to as CP) connected to system bus 1.
) 2 and various interfaces (I/F) 3
-5, memories 6-10, and control blocks 11.12.

The CPU 2 is a circuit that controls the entire device and performs arithmetic processing on various data. This CPU2 is
A work memory 1 stores received image data by an image data control program serving as an image data control means.
0, and if there is previous image data on the work memory 10 for the received image data, it combines the dots at the boundary between the previous image data and the received image data to form multiple dots. Data processing is performed as a unit. The image data control program is stored in a program memory to be described later, and the CPU 2 reads this program and executes image data control.

The interface includes host I/F3 and panel I/F3.
There are F4 and recording unit I/F5. Host 1/F3 is
This is a circuit that receives code data input from a host computer (not shown) in accordance with, for example, the R3232C standard. The panel 4 also includes a panel 24 operated by an operator.
This is a circuit that relays the instruction signal 4a input from (FIG. 2). The recording unit 1/F5 is a circuit that relays signals such as those described in FIG. 2, which are exchanged between the image supply device 21 and the recording unit 22.

The memories include a character pattern memory 9, a bitmap memory 6, a RAM (random access memory) 7, a program memory 8, and a work memory 10. The bitmap memory 6 stores, for example, one page of images to be recorded on the recording paper 29 in the recording section 22 (FIG. 2).
This is a circuit that stores data in bitmap format. RAM7 is
Various data for CPU2 operation and host I/F
This circuit is used for storing the code data input from 3. The program memory 8 is the CPU 2
This circuit stores a control program for the operation of the image data controller and an image data control program which is an image data control means. The character pattern memory 9 is a so-called font memory, and is a memory that stores character patterns composed of a dot matrix. Work memory 1
0 is a memory that temporarily stores image data created and edited on a workstation or the like, and can store two blocks of divided image data.

As a control block, the bitmap controller 11
, PTC12. bitmap controller 11,
This circuit controls the access timing and address to the bitmap memory 6, and controls the transfer of image data formed in the bitmap memory 6 to the recording section 1/F5.

The PTC 12 is a known programmable timer counter, and is a circuit that measures time and the like and generates timing.

Next, the processing procedure of the CPU 2 when performing image data control will be explained based on the flowchart of FIG. 4.

First, the CPU 2 receives a block of image data (hereinafter referred to as image data) transmitted from a workstation, etc., and stores it in the work memory 10 (step 1
01). Next, the previous image data (
In step 102), it is determined whether or not there is image data (hereinafter referred to as image data). (Step 103).

When the final line of the image data arrives (step 104), the CPU 2 selects the final line of the image data ■ and the image data ■.
The dots on the first line are combined, data processing is performed in units of multiple dots, and the data is developed on the bitmap memory 6 (step 105).

Next, the CPU 2 determines whether data reception for one page has been completed (step 106).

To determine whether one page of data has been received,
This is determined by the page end code inserted in the final data block. Here, if the printing for one page has not been completed, the process returns to step 101, and if the data reception for one page has been completed, the work memory
It is determined whether there is any remaining data within 0 (step 107). Here, if there is remaining data, data processing is performed on the remaining data (step 108).
), then the image data on the bitmap is sent to the recording unit I/F.
5 (step 109).

Note that when one page of images consists of image data 20 to image data (2), the determination in step 106 is made when the final data block, image data (2), is stored. Regarding this image data (2), since there is no need to consider processing at the data boundary, the data in the front row is used as is, as in the conventional case, or the dots in the corresponding part are treated as white.

The deterioration in image quality in this case is practically negligible.

〔Effect of the invention〕

As explained above, in the image processing apparatus according to the present invention, received image data is temporarily stored in a storage means such as a work memory, and the previous image data of the received image data is stored in the storage means. When the image data exists at the boundary of the divided image data, the dots at the boundary between the previous image data and the received image data are combined and data processing is performed using multiple dots as the μ position. It is possible to eliminate missing dots.

Therefore, it is possible to eliminate distortions and smudges that occur at the boundaries of data, and it is possible to obtain a printed image with excellent image quality.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the specific circuit configuration of the image supply device, Fig. 2 is a block diagram showing an overview of the laser beam printer, Fig. 3 is a perspective view of main parts showing an example of the recording section, and Fig. 4 5 is a flowchart showing the processing procedure of the CPU when performing image data control, FIG. 5 is a diagram of the principle of the distance inverse proportionality method, and FIG. 6 is an explanatory diagram showing an example of a sent image. 2...Microprocessor (CPU), 5...Recording section 1/F, 6...Bitmap memory, 7...R
A.M. 10...Work memory, 1...Bitmap controller. Figure 2 Figure 3 Original figure ○○○・Processed figure ○○○○○○ Figure 5

Claims (1)

[Claims] In an image processing device that processes received image data in units of multiple dots and forms a dot image corresponding to a recorded image in a bitmap memory, the image data is divided into multiple blocks. storage means for storing the received image data, and storing the received image data in the storage means;
Regarding the received image data, when the previous image data exists on the storage means, combining the dots at the boundary between the previous image data and the received image data,
An image processing device comprising: an image data control unit that performs data processing in units of multiple dots.