JP3058189B2 - Image receiving and recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image receiving and recording apparatus suitable for a facsimile, a printer and the like.

[0002]

2. Description of the Related Art The importance of image communication such as facsimile has been increasing more and more in recent years, and the demand for image quality has been increasing. Therefore, a device that is excellent in gradation expression and capable of high-speed communication has been demanded. Against this background,
The multi-level signal is binarized and transmitted by the communication device using a pseudo gradation expression method such as a dither method or an error diffusion method, and the receiver processes and records the received signal as it is as a binary signal. Devices are gradually spreading.

In recent years, as such a recording apparatus, an ink jet printer has been developed which discharges ink from a discharge port toward a recording material using a bubble generated by thermal energy to record characters, images, and the like. In this printer, the size of a heating resistor (heater) provided in each discharge port is much smaller than that of a piezoelectric element used in a conventional ink jet printer. A high-quality recorded image can be obtained, and it has characteristics such as high speed and low noise.

[0004]

However, it is difficult to uniformly manufacture a plurality of printing elements in a printing head having a plurality of printing elements, for example, a multi-nozzle ink jet head or a thermal head. Some variation occurs in the characteristics. For example, in a multi-nozzle ink jet head, the nozzle shape and the like vary, and in the thermal transfer thermal head, the heater shape and the resistance value vary. The non-uniformity of the characteristics between the printing elements results in the non-uniformity of the size and density of the dots printed by the printing elements, resulting in density (image) unevenness in the printed image. This image unevenness has significantly reduced the quality of the received image. In addition, especially in the communication of color images, there is a problem that color unevenness and color reproduction errors occur and image quality deteriorates.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to obtain a high-quality image capable of high-speed communication and reducing density unevenness regardless of a compression rate of a received image signal. It is an object to provide a possible image receiving and recording device. Another object of the present invention is to provide an image receiving and recording apparatus capable of high-speed communication and capable of obtaining a high-quality image with reduced density unevenness while enhancing gradation expression power from a received image signal. It is in.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided an image receiving and recording apparatus for recording a received image signal using a recording head having a plurality of recording elements arranged therein, and for expanding a received binary compressed image signal. Decoding means for converting the binary image signal expanded by the decoding means into a multi-valued image signal; and driving the recording head based on the binary image signal expanded by the decoding means. A multi-valued image signal output from the conversion unit, based on a measuring unit that measures an interval, and a drive interval of the recording head measured by the measuring unit, the characteristic variation between a plurality of recording elements of the recording head; A modulating means for modulating the data to be corrected; and a driving means for driving the recording head based on the image signal modulated by the modulating means to perform image recording. The features. Further, according to the present invention, a plurality of recording elements are arranged, and a plurality of recording heads capable of recording similar colors at dark and light densities are used. Converting means for converting a binary image signal into a multi-valued image signal; and distributing means for distributing the multi-valued image signal output from the converting means to a plurality of recording heads capable of recording at the dark and light densities. A modulating means for modulating the multi-valued image signal output from the allocating means so as to correct a characteristic variation among a plurality of recording elements of the plurality of recording heads; and Driving means for driving the plurality of recording heads to perform image recording.

[0007]

According to the above arrangement, since a binary image signal is communicated, high-speed communication is possible, and a characteristic variation between recording elements is corrected based on the driving interval of the recording head by converting the multi-valued image signal. Since the modulation is performed as much as possible, it is possible to obtain a high-quality image with reduced density unevenness regardless of the compression ratio of the received image signal. Further, according to the above configuration, the multi-valued image signal is distributed to a plurality of recording heads capable of recording in dark and light densities, and the distributed image signal is subjected to characteristic variations among recording elements of the plurality of recording heads. Therefore, it is possible to obtain a high-quality image from the received image signal, in which the gradation unevenness is reduced and the density unevenness is reduced, from the received image signal.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[0009]

FIG. 1 shows a block diagram of a first embodiment.
In the figure, a full-color image signal is binarized by an error diffusion method as a method of pseudo-gradation expression, and an RGB signal is represented by M
The data is compressed and coded by the MR (Modified Modified Read) method and transmitted to the line interface 10. The signal received by the line interface 10 is expanded by the decoder 11 and demodulated to the original RGB binary bitmap signal. Thereafter, the binary / multilevel converter 12 performs multilevel conversion by a two-dimensional filtering operation. Here, a multi-level signal of 128 gradations was obtained using a 3 × 3 matrix.

Next, with respect to the RGB signals of 128 gradations,
Masking processing and UC to correspond to the characteristics of the printer
The R processing operation is performed by the color calculator 13 to obtain C, M, Y, and Bk signals of 128 gradations.

Next, the unevenness correction modulator 1
4 performs unevenness correction modulation. The printer used here uses a multi-nozzle ink jet recording head 9 in which 128 elements are arranged at a pitch of 400 dpi for each color. A schematic diagram of the mechanism is shown in FIG.

In FIG. 2, a recording material 5 wound in a roll is sandwiched between feed rollers 3 via transport rollers 1 and 2 and driven by a sub-scanning motor 4 coupled to the feed rollers 3. It is sent in the direction f in the figure. Guide rails 6 and 7 are placed in parallel across the recording material 5, and an ink jet recording head 9 mounted on a carriage 8 scans left and right.

The recording head 9 causes a state change such as film boiling in the ink by thermal energy, and discharges the ink from a discharge port (nozzle) toward a recording material by using generated bubbles. Type recording head,
Suitable for binary recording.

The recording material 5 is intermittently fed by the sub-scanning motor 15 so that the recorded images are continuous. When the recording material 5 is stopped, the recording head 9 scans in the P direction by a main scanning motor (not shown), and discharges ink droplets according to the supplied image signal. In this way,
A desired recording image is formed over the entire surface of the recording material 5 by the relative movement between the recording head 9 and the recording material 5.

The print head 9 has 128 print elements (128 ink discharge nozzles in the case of this embodiment).
They are arranged in a line at a pitch of μm (400 dpi), and a minute difference in the amount of ink ejected from each element causes image unevenness in the recorded image.

Therefore, the variation of the ejection amount specific to each element is measured in advance and stored in a memory as correction data, and the signal is modulated so as to correspond to the characteristic shown in FIG. That is, when the discharge amount is a standard value, as shown in C, 1:
A signal equal to 1 is obtained after the modulation, and the modulation amount is set according to the deviation from the standard value so that the value after the modulation becomes smaller as indicated by A and B for the element having a large ejection amount. I do. In the opposite case, modulation is performed as in D or E. In this embodiment, there are 64 types of correction characteristic tables for correcting the variation in the discharge amount of each element.

In this manner, C, M,
The Y and Bk signals are subjected to gradation correction (γ correction) by a gradation corrector (not shown), and then the signals of 128 gradations are binarized by the error diffusion method using the multi-level binary converter 15. This binary signal is sent to the head 9 through the head drive circuit 16 to obtain a high quality image.

As described above, since the RGB binary signal is compressed and transmitted, high-speed communication is possible. Further, in the system of this embodiment, since signals that are not affected by the characteristics of the terminals such as the transmission side (reader) and the reception side (printer) are transmitted, the advantage of an open system can be obtained.

By converting the RGB binary signals transmitted at a high speed into multi-level signals, precise color calculations can be performed so that a color image can be obtained with high image quality. Further, since the multi-level signal is modulated according to the element variation, uniform gradation recording can be obtained using a highly reliable and stable binary printer.

[0020]

Second Embodiment Next, a description will be given of a second embodiment in which the image quality can be further improved by changing the modulation amount in accordance with the change in the recording speed in the unevenness correction modulator.
This is to cope with the fact that, when an image is transmitted after being compressed, the compression ratio varies greatly depending on the location of the image depending on the image of the document, and thus the recording speed changes.

FIG. 4 is a schematic configuration diagram of a printer using a so-called full multi-head in which recording elements are arranged over the entire recording width.

In the figure, heads 29 are Y, M, C,
About 4700 printing elements are arranged in one row at a pitch of 400 dpi for each color of Bk, and have a printing width of 297 mm. 13 is a capping unit for capping the head 29, 14 is a charging / adsorbing belt for adsorbing paper, 15
Denotes a back platen, 16 denotes a paper feed cassette, and 17 denotes a recording sheet. 18 is a pickup roller, 19 and 21 are transport rollers, 20 is a transport path, 23 is a heater, 24 is a fan,
25 is a discharge roller and 26 is a tray.

FIG. 5 is a block diagram showing the control configuration of FIG. In the figure, parts having the same functions as those in FIG.

37 to 39 are recording heads 29Y to 29B
A data buffer for correcting the delay between k and a counter 40 for measuring a time interval of each line.
The counter 40 measures the interval between signals output each time data of one line is received from the decoder 31. The unevenness correction modulator 34 performs unevenness correction according to the line interval time, that is, the drive frequency of the recording element.
This corresponds to the fact that when the driving frequency of the printing element changes, the state of density unevenness changes.

Here, the interval time T between lines is set to 250
125 from the minimum time of μsec to 1 sec or more
The recording element is divided into eight sections every μsec, and the characteristics (variation of the ejection amount) of each printing element are measured in advance for each section, and for example, any of the correction characteristics A to E shown in FIG. It is stored in a memory as correction data indicating whether or not. Then, using this correction data, the input signal is modulated in accordance with the interval time T between the lines to correct the density unevenness.

As described above, in this embodiment, the recording speed (driving frequency) changes in accordance with the change in the image compression ratio, and the density unevenness caused by the change is corrected by modulating the input signal according to the recording speed. ing. Thereby, a higher quality image can be obtained.

In this embodiment, the image compression ratio is mentioned as a factor of fluctuation of the recording speed (driving frequency). However, the recording speed also varies depending on the transmission speed of the line. Therefore, the same effect can be obtained even if the input signal is modulated according to the transmission speed.

[0028]

Third Embodiment Next, a description will be given of an embodiment in which the present invention is applied to a printer in which the gradation expression ability is enhanced by a dark and light ink recording method in which similar colors are expressed by dark ink and light ink. This embodiment is also very effective because it is sufficient to receive binary RGB signals in the same manner as in the first embodiment shown in FIG. 1 and to change the subsequent processing.

FIGS. 6 and 7 are a schematic configuration diagram and a block diagram showing the present embodiment, respectively. FIGS. 1 and 2 show the first embodiment.
Corresponding reference numerals are assigned to portions corresponding to and the description is omitted. In FIG. 6, only the Y color is used as the dark ink only, and M, C,
The color of Bk is such that each head 49Y, 49M-dark, 49M-light, 49C-dark,
9C-light, 49Bk-dark, and 49Bk-light correspond. The shade sorter 57 in FIG. 7 outputs the recording signals for dark ink and light ink by performing the operation shown in FIG. 8 for each of the colors M, C, and Bk.

As described above, in this embodiment, since the binary image signal is converted into the multi-valued image signal to perform the gradation distribution and the unevenness correction, the gradation expression capability is improved and the high quality is achieved. Images can be obtained.

[0031]

Other Embodiments In the embodiments described above, the printer is an ink jet recording apparatus, but the present invention is also applicable to recording apparatuses such as thermosensitive recording and electrophotographic recording. Further, the present invention is not limited to the binary recording method. Further, the present invention is not limited to an apparatus using a multi-element head unless it is limited to color printing. For example, after the binary / multilevel conversion, modulation may be performed in accordance with the gradation characteristics of one element.

The present invention brings about an excellent effect particularly in a recording head and a recording apparatus of a type in which a state change is caused in ink by using thermal energy and the ink is ejected among ink jet recording systems. .

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal transducer, and the film is heated on the heat-acting surface of the recording head. As a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with the drive signal, which is effective. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble,
Form at least one drop. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. Examples of the drive signal in the form of a pulse include U.S. Pat. Nos. 4,463,359 and 4,345.
No. 262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,558,333 which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 459600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication (Kokai) No. 123670/1984 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing pressure waves of thermal energy. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration corresponding to a discharge unit.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, a combination of a plurality of recording heads as disclosed in the above-mentioned specification makes the length longer. The present invention can exhibit the above-mentioned effects more effectively, although it may be either a configuration that satisfies the above requirements or a configuration as a single recording head formed integrally.

In addition, the print head is exchangeable with a print head of a chip type, which can be electrically connected to the main body of the apparatus or supplied with ink from the main body of the apparatus, or is integrated with the print head itself. The present invention is also effective when a cartridge-type recording head provided in a fixed manner is used.

It is preferable to add recovery means for the recording head, preliminary auxiliary means, and the like provided as components of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. To be more specific, a capping unit, a cleaning unit, a pressure or suction unit, a preheating unit using an electrothermal converter, another heating element, or a combination thereof, for the recording head. ,
Performing a preliminary ejection mode in which ejection is performed separately from printing is also effective for performing stable printing.

Further, the printing mode of the printing apparatus is not limited to the printing mode of only the mainstream color such as black, and may be a single-color printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of full colors by color mixture.

In the embodiments of the present invention described above, liquid ink is used. However, in the present invention, an ink which is solid at room temperature or an ink which becomes soft at room temperature is used. Can be used. In general, in the above-described ink jet device, the temperature of the ink itself is adjusted within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. It is sufficient if the ink is in a liquid state.
In addition, positively prevent the temperature rise due to thermal energy by using the energy of the state change of the ink from the solid state to the liquid state, or use ink that solidifies in a standing state to prevent evaporation of the ink. In any case, heat energy is applied by heat energy, such as one in which ink is liquefied and ejected as an ink liquid by application of heat energy according to a recording signal, or one which already starts to solidify when reaching a recording medium. The use of an ink that liquefies for the first time is also applicable to the present invention. In such a case, as described in JP-A-54-56847 or JP-A-60-71260, the ink is held as a liquid or solid substance in the concave portion or through hole of the porous sheet, It is good also as a form which opposes an electrothermal transducer. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

[0040]

As described above, according to the present invention, high-speed communication can be performed, and a high-quality image with reduced density unevenness can be obtained regardless of the compression ratio of a received image signal. . Further, according to the present invention, it is possible to obtain a high-quality image from a received image signal in which density unevenness is reduced while enhancing gradation expression power.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a first embodiment.

FIG. 3 is a diagram illustrating the operation of the unevenness correction modulator.

FIG. 4 is a schematic configuration diagram of a second embodiment.

FIG. 5 is a block diagram illustrating a control configuration according to a second embodiment.

FIG. 6 is a schematic configuration diagram of a third embodiment.

FIG. 7 is a block diagram illustrating a control configuration according to a third embodiment.

FIG. 8 is a diagram for explaining the operation of the shade sorter.

[Explanation of symbols]

 9, 29, 49 Head 10, 30, 50 Line interface 11, 31, 51 Decoder 12, 32, 52 Binary multi-value switch 14, 34, 54 Non-uniformity correction modulator 37, 38, 39 Data buffer 40 Counter 57 Shade Sorter

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-114379 (JP, A) JP-A-62-188552 (JP, A) JP-A-2-109465 (JP, A) JP-A-3- 274965 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) H04N 1/40-1/409 H04N 1/46 H04N 1/60

Claims (8)

(57) [Claims] 1. An image receiving and recording apparatus for recording a received image signal using a recording head in which a plurality of recording elements are arranged, comprising: decoding means for expanding a received binary compressed image signal; Converting means for converting a binary image signal expanded by the decoding means into a multi-valued image signal; measuring means for measuring a drive interval of the recording head based on the binary image signal expanded by the decoding means; A modulating unit that modulates a multi-valued image signal output from the converting unit based on the driving interval of the recording head measured by the measuring unit so as to correct a characteristic variation among a plurality of recording elements of the recording head; And a driving unit for driving the recording head based on the image signal modulated by the modulation unit to record an image. Recording apparatus. 2. The image processing apparatus according to claim 1, wherein the driving unit converts the image signal modulated by the modulation unit into a binary image signal.
2. The image receiving and recording apparatus according to claim 1, wherein the recording head is driven by a value image signal. 3. The image receiving and recording apparatus according to claim 1, wherein the recording head records the received image signal in a plurality of colors. 4. The image receiving and recording apparatus according to claim 3, wherein the recording element of the recording head has an ink discharge port for discharging ink. 5. A recording element of the recording head includes a thermal energy generating means for causing a state change of the ink due to heat and discharging the ink from an ink discharge port based on the state change to form flying droplets. 5. The image receiving and recording apparatus according to claim 4, comprising: 6. An image receiving and recording apparatus for recording a received image signal by using a plurality of recording heads each having a plurality of recording elements arranged therein and capable of recording similar colors at dark and light densities. Conversion means for converting a value image signal into a multi-valued image signal; and distribution means for distributing the multi-valued image signal output from the conversion means to a plurality of recording heads capable of recording at the dark and light densities. A modulating means for modulating a multi-valued image signal output from the allocating means so as to correct a characteristic variation among a plurality of recording elements of the plurality of recording heads; and An image receiving and recording apparatus comprising: a driving unit that drives a plurality of recording heads to perform image recording. 7. The driving means converts the image signal modulated by the modulation means into a binary image signal.
7. The image receiving and recording apparatus according to claim 6, wherein the recording head is driven by a value image signal. 8. The image receiving and recording apparatus according to claim 6, wherein the recording element of the recording head has an ink ejection port for ejecting ink.