JP2854329B2 - Image recording method and apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording method and apparatus, and more particularly, to an image recording method and apparatus for recording images such as characters, graphics, and various signal waveforms according to recording data. About.

[Prior Art] Conventionally, in this type of apparatus, an image is recorded at a relatively slow and fixed paper feeding speed due to cost and the like. now,
Assuming a paper feed speed = 5 mm / S and a resolution of 20 lines / mm,
In the paper feed direction, recording may be performed at a rate of one pixel per 10 ms.
By the way, there is a demand for increasing the recording speed without increasing the cost. However, in the above case, for example,
If the magnification is 10 times, it is necessary to record at a rate of one pixel per 1 ms in the paper feed direction. For this reason, the black density per pixel changes, and the image quality as a whole changes. Further, for example, when a thermal type printing head is used, there is a problem that the head life is reduced by continuous heating.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned prior art, and an object of the present invention is to provide an image recording method and an image recording apparatus with little change in image quality even if the recording speed is increased. To provide.

Another object of the present invention is to provide an image recording method and an image recording apparatus in which the load on the print head is reduced even when the recording speed is increased.

Means for Solving the Problems To achieve the above object, an image recording method according to the present invention is an image recording method for sequentially recording images in accordance with recording data. The outline is to determine the current recording data based on the N pieces of pixel data going back and the M pieces of recording data going back from the current time.

Further, in order to achieve the above object, the image recording apparatus of the present invention has a printing element for sequentially recording an image in accordance with print data, and N pixel data DT1 to DTN and N pixel data DT1 to DTN of the printing element which are retroactive from the present time. A storage unit for sequentially storing M pieces of recording data HT1 to HTM that are retroactive to the past from the present time, and the present pixel data DT0 when recording by the printing element.
And N pixel data DT1 read from the storage means.
DDTN and M pieces of recording data HT1 to HTM will determine the current recording data HT0.

Preferably, the determination means determines the current recording data HT0 according to the recording device.

 Preferably, the determination means has a logical operation term of HT0 = DT0 * DT1 / * DT2 / * HT1 / * HT2 / where / represents negative logic.

 Preferably, the determination means has a logical operation term of HT0 = DT1 * DT2 / * HT2 / where / represents negative logic.

 Preferably, the determination means has a logical operation term of HT0 = DT0 * DT2 * HT2 /, where / indicates negative logic.

Preferably, the determination means has a logical operation term of HT0 = DT1 / * DT2 * HT3 / which functions when the recording speed is high.

[Operation] In the above configuration, the printing element sequentially records images according to the recording data. On the other hand, the storage means stores N pieces of pixel data DT1 to DT
And M pieces of recording data HT1 to HTM which go back from the present time to the past are sequentially stored. Then, at the time of recording by the printing element, the determination means determines the current recording data HT0 based on the current pixel data DT0 and the N pieces of pixel data DT1 to DTN and the M pieces of recording data HT1 to HTM read from the storage means. decide. Preferably, the determining means determines the current recording data HT0 according to the recording speed.

[Description of Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of an image recording apparatus to which the image recording method of the embodiment is applied. In the figure, reference numeral 1 denotes a CPU, which performs main control of the embodiment device. Reference numeral 2 denotes a ROM that stores various fixed information. For example, 2-1 is a program storage area, and a control program (not shown) executed by the CPU 1
Is stored. 2-2 is a character energy generator (C
G) A storage area for storing binary pattern information corresponding to code information such as characters and figures. As an example of the binary pattern information, 2-3 is grid pattern information, and the CPU 1 executes such grid pattern information 2-3.
By arranging a plurality of, a grid pattern in the form of a grid can be developed in the image memory 7.

A RAM 3 is used by the CPU 1 as a work area. The RAM 3 also temporarily stores code information such as characters, graphics, and measurement signals to be recorded. These pieces of code information are sent from various remote medical measurement devices (not shown).
Reference numeral 4 denotes a console (CSL), which includes switches, a display, and the like necessary for operation. 5 is a communication line (for example, LAN)
And is connected to various remote medical measurement devices.
Reference numeral 6 denotes a communication control interface (DCI) which controls communication with the medical measurement device via the communication line 5. 7
Is an image memory (IM) in which pattern information corresponding to various types of code information in the RAM 3 is bit-mapped. 8
Denotes a heat controller (HC) that performs information processing according to the present invention on the image data (I-DATA) of the IM7 and outputs the resulting record data (P-DATA). Reference numeral 9 denotes a printer (PRN) which receives P-DATA from the heat controller 8.
Accordingly, the thermal head arrays 9-1 arranged in a vertical line are driven in parallel, and an image is recorded on a recording sheet by a so-called raster method.

 10 is a common bus of CPU1.

FIG. 2 is a block diagram of the heat controller 8 of the embodiment. In the figure, a parallel-serial converter 81 converts 8-bit parallel I-DATA into serial data DT according to a clock signal (not shown).
Reference numeral 82 denotes a flip-flop (FF), which is a serial data DT.
Are sequentially stored and the current pixel data DT0 is output. 83
Is a RAM, for each element of the thermal head 9-1, two pieces of pixel data DT1 and DT2 which go back from the present time to the past, and six pieces of record data which also goes back to the past from the present time (data actually recorded in the past). ) Store HT1 to HT6. In addition, RAM83
Address input of HA00-HA10 is a total of 11 bits,
This address is synchronized with the clock signal and addresses 0 to 20
By incrementing to 47, the past information (8 bits each) of a total of 2048 printing elements is sequentially read out and the storage is updated. Reference numeral 84 denotes a latch (LATCH) for temporarily storing past data read from the RAM 83.

Reference numeral 85 denotes a programmable array logic (PAL), which is the current pixel data DT0 from the FF82, the pixel data DT1 and DT2 read from the RAM83 which goes back to the past, the recording data HT1 to HT6 which goes back from the present to the past, and the CPU1. It receives the 3-bit speed mode signal (SPEED) sent from the controller as input and outputs the current recording data (pixel data to be actually recorded) OD1 / or OD2 /. In addition, such PAL8
Functions equivalent to 5 can also be configured in ROM. Next, these recording data OD1 /, OD2 / are NORed by a NOR circuit 86 to become recording data P-DATA. This P-DATA is also called the current recording data HT0. Reference numeral 87 denotes, for example, an open collector type buffer circuit (BUF) for updating data stored in the RAM 83. That is, the pixel data DT0 and DT1 at the present time are replaced with the past pixel data DT1 and DT2 to read the past data at the next time for the same printing element.
Then, the recording data is updated in the RAM 83 using the recording data HT0 to HT5 at the present time as the past recording data HT1 to HT6.

FIG. 3 is a conceptual diagram illustrating information processing in the programmable array logic (PAL) 85 of the embodiment.
In the figure, X is the direction in which the recording paper advances, and has a resolution of, for example, 40 dots / mm. Y is a direction in which 1728 thermal head elements are arranged in one line, and each element is, for example, 8
They are arranged in dots / mm. In this way, by setting the resolution in the relationship of X> Y, the recording dot in the X direction corresponding to one black bit of the pixel data is set to the recording speed (eg, medium speed = 25 mm / S, high speed = 50 mm / S). Accordingly, the density is changed within the range of 2 to 4 dots, and as a result, the black density given to the eyes is made uniform.

FIG. 3 shows the 99th to 101st thermal head elements 9
9 to 101 are shown. Attention is now focused on information processing for the 100th thermal head element 100. Pixel data (recording data) to be actually recorded is HT0. However, HT0 = 0 (white dot) or HT0 = 1 (black dot)
The current pixel data DT0, the past pixel data DT1 and DT2 read from the RAM 83, and the past recording data HT1
HT6 and the recording speed mode signal (SPEED) sent from the CPU 1 and is determined by the following logical expression.

When the mode signal is 0 (high speed) Item 0D1 / = DT1 / * DT2 * HT3 / ... B When the mode signal is 0 or 1 (medium speed) Item 0D2 / = DT0 * DT2 * HT2 / ... D + DT1 / * DT2 * HT2 / ... F + DT1 / * DT2 / * HT2 / ... G + DT0 * DT1 / * DT2 / * HT1 / * HT2 / ... H + DT0 / * DT1 / * DT2 * HT1 / * HT2 * HT3 * HT4 / * HT5 / * HT6 / ... I That is, when the mode signal is 0 (high speed), B, D, F, G, H, I
Each logical operation term functions, and when the mode signal is 1 (medium speed), each logical operation term of D, F, G, H, and I functions.

Each of the above logical operation terms takes into consideration the effects of the resolution, recording speed, and the like of this embodiment on the visual sense. If the conditions such as the resolution and the recording speed change, the logical operation term can change.
Here, it is easy to use the above logical expression if it is written as shown in Tables 1 and 2.

4 to 9 show the programmable array of the embodiment.
FIG. 3 is a diagram for explaining the function of each logical operation term in a logic (PAL) 85.

First, Fig. 4 shows that a series of pixel data is "... 001000 ..."
Is printed at a high speed. That is, in this case, the center pixel data = 1 is isolated by considerable zeros before and after, and must be recorded at high speed. Therefore, the number of black print data is increased. First, at time t = 5, the H term is satisfied, and the recording data becomes 1. That is, the H term is a term that changes the recording data to 1 by capturing the point in time when the pixel data changes from 00 to 1. However, it is necessary that at least the recording data at the time of t = 3, 4 is 0. Next, at time t = 6, the G term is satisfied, and the recording data becomes 1. That is, the G term is 001 in this case.
The black dot recorded in the following order is further extended by one dot.
It is a term to be. This gives a slight increase in black density to the eye, but is still not enough to record at high speed. Next, at time t = 7, item B is satisfied, and the recording data becomes 1. However, item B works only at the time of high-speed printing. That is, in this case, the black dot recorded in the order of 0011 is further extended by 1 dot to 00111. As a result, a group of isolated black recording dots can be clearly identified. Next, at the time t = 8, the I term is satisfied, and the recording data becomes 1. However, in order to satisfy the item I, the recording data at least at the time t = 2 before must be 0. That is,
In this case, the I term is a term corresponding to 0001111 by further extending the black dot by one dot when 0 is recorded even at t = 2. As described above, by changing the extension number of the black dots depending on how long the white dots have been recorded in the past, the group of black dots to be recorded is further clarified.

FIG. 5 shows a case in which the pixel data "..001000 .." is printed at a medium speed. In other words, in this case, since recording is performed at a medium speed, one dot of the black recording itself has a somewhat dark density. Therefore, it is not necessary to increase black recording data. First, at time t = 5, the H term is satisfied in the same manner as described above, and at the next time t = 6, the G term is satisfied. Therefore, the recording data so far becomes 0011. However, at the next point of time t = 7, the high-speed recording is not performed, so that the B term is not satisfied. Further, at the next time t = 8, the B term was not satisfied at the immediately preceding time t = 7, so the I term was not satisfied. Therefore, at medium speed, the recorded data is 001100
In this pattern, the resulting black density that is given to vision is made uniform.

FIG. 6 shows that a series of pixel data is "..0010101010 .."
Is printed at a high speed. In this case, it is desired to reproduce the image without losing the density pattern in which white and black pixels alternate in the middle. Moreover, because it is a high-speed recording, the first 001
Only the part needs to be clear. In this case as well, the H term is satisfied at time t = 5, and the G term is satisfied at time t = 6. Therefore, the recorded data is first 0011
become. At the next time t = 7, high-speed printing is performed, so that the black dot is further extended by satisfying the item B. However, the next t =
At time 8, the portion of the pixel data DT becomes 010, which indicates that the pixel data DT0 = 1 at the previous time t = 5 was not isolated in a considerable range before and after that. Does not satisfy item I. Further, at the next time t = 9, the black dot is recorded at the time t = 7 before the time t = 9. Therefore, it is necessary to secure a white dot to hold the black and white density pattern. . Therefore, the recorded data so far becomes 0011100. At the next time t = 10, the white dot is recorded at the time t = 8 two times before, so that the G term is satisfied, and the recording data becomes 1. The next t =
At the time of 11, since high-speed recording is performed, the black dot is further extended by satisfying item B. Therefore, at high speed, the recorded data is
0011100110, resulting in visually giving the same density pattern as the original pixel data array.

FIG. 7 shows that the pixel data is "..0010101010 .."
Is printed at medium speed. Similarly, at time t = 5, the H term is satisfied, and at time t = 6, the G term is satisfied. Therefore, the recording data first becomes 0011. However, at the time t = 7, medium-speed recording is performed, so that the item B is not satisfied. At t = 8, a black dot is recorded at t = 6 two times before, so a white dot is secured here. Therefore, the recorded data so far becomes 001100. Further, at time t = 9, the white dot is recorded at time t = 7 two times before, so that the D term is satisfied, and the recording data becomes 1. At the next time t = 10, the white dot was recorded at the time t = 8 two times before, so that the G term is satisfied, and the recording data becomes 1. Therefore, in the case of the medium speed, the print data has an array of 001100110, and as a result, the same density pattern as the original array of pixel data is visually provided.

FIG. 8 shows that a series of pixel data is "..0011111111 .."
Is printed at a high speed. In this case, black dots are formed all along the way, so that overheating of the thermal head element must be prevented. Therefore, black dot recording is thinned out. Similarly, at the time t = 5,6, the H and G terms are satisfied, and the recorded data so far becomes 0011. At the next time t = 7,8, black dots are recorded at two time points t = 5,6, respectively, so white dots are secured here. Therefore, the recorded data so far becomes 001100. At the next time points of t = 9 and 10, white dots are recorded at the respective time points of t = 7 and 8 two before, respectively, so that each of them satisfies the D term. Therefore, the recording data so far becomes 00110011. Thus, at high speed, the recorded data is 0011001100
This prevents overheating of the thermal head element.

FIG. 9 shows that the pixel data is "..0011111111 .."
Is printed at medium speed. In this embodiment, the data processing in this case is the same as in FIG. 8 for preventing overheating of the thermal head element.

Note that each logical operation term shown in the above embodiment is merely an example. That is, according to the idea of the present invention, the recording density is made uniform under various recording speeds, and / or for the purpose of reducing the load on a printing element such as a thermal head element.
Various other logical operation terms can be configured and can be added to the embodiment device. For example, in the above-described embodiment, as a result of taking into account the prevention of overheating of the thermal head, for example, the recording pattern of the result is the same in the case where pixel data is printed at high speed and the case where printing is performed at medium speed. However, it is not limited to this. Alternatively, for example, the recording pattern at a high speed may be 0011101110, and the recording pattern at a medium speed may be 0011001100.

In the above embodiment, the pixel data and the recording data are binary, but the present invention is not limited to this. Even when the pixel data and the recording data are multi-valued, the logic of whether or not to record the target pixel according to the present invention can be applied.

[Effects of the Invention] As described above, according to the present invention, portions that are too dark are made lighter, and portions that are too light are made darker. Even if the recording speed is increased, the life of the print head is extended because the load on the print head is small.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image recording apparatus to which the image recording method of the embodiment is applied. FIG. 2 is a block diagram of a heat controller 8 of the embodiment. FIG. 3 is a programmable array logic (PAL) of the embodiment. 4 to 9 are diagrams for explaining the function of each logical operation term in the programmable array logic (PAL) 85 of the embodiment. In the drawing, 1 ... CPU, 2 ... ROM, 2-1 ... Program storage area, 2-2 ... Character generator (CG) storage area, 2-3 ... Grid pattern information, 3 ... RA
M, 4 ... Console (CSL), 5 ... Communication line, 6 ...
Communication control interface (DCI), 7 image memory (IM), 8 heat controller (HC), 9 printer (PRN), 9-1 thermal head array.

Claims (7)

(57) [Claims] An image recording method for sequentially recording images according to recording data, comprising: a current image data, N pieces of pixel data that goes back to the past from the current time, and M pieces of recording data that goes back to the past from the current time. An image recording method characterized by determining current recording data. 2. A printing element for sequentially printing an image in accordance with print data, N pieces of pixel data DT1 to DTN of the print element which go back from the present time and M pieces of print data HT1 to HT1 which go back to the present time. A storage unit for sequentially storing HTMs, and pixel data at the current time when recording by the printing element.
DT0 and N pixel data D read from the storage means
An image recording apparatus comprising: determination means for determining current recording data HT0 from T1 to DTN and M recording data HT1 to HTM. 3. The apparatus according to claim 2, wherein said determining means determines the current recording data HT0 according to the recording speed.
Item. 4. The apparatus according to claim 3, wherein said determining means has a logical operation term of HT0 = DT0 * DT1 / * DT2 / * HT1 / * HT2 / where / represents negative logic. Image recording device. 5. The image recording apparatus according to claim 3, wherein said determining means has a logical operation term of HT0 = DT1 * DT2 / * HT2 /, where / represents negative logic. 6. The image recording apparatus according to claim 3, wherein said determining means includes a logical operation term of HT0 = DT0 * DT2 * HT2 / where / represents negative logic. 7. The image recording apparatus according to claim 3, further comprising a logical operation term of HT0 = DT1 / * DT2 * HT3 / which functions when the recording speed is high.