JPH04167669A - Picture transmission equipment and method and equipment for picture transmission/reception - Google Patents

Abstract

PURPOSE:To transmit/receive a picture having a proper density with little bits of information by providing a picture transmission equipment with a means which corrects the density in accordance with correction data which corrects the recording density of the recording head of a picture reception equipment. CONSTITUTION:In a facsimile A, a transmission document is read by a reading part 21a and the picture is processed by a picture processing part 22a and is sent to a density correction ROM 31a. This ROM 31a selects the inclination of a line in accordance with the signal from a density correction RAM 32a to correct the density. At this time, for example, when the picture recording part 24b of a facsimile B as the transmission destination is a 256-nozzle inject printer, an optimum inclination corresponding to the density of this head is stored as correction data. Since picture data sent to the facsimile B has the density corrected in accordance with the picture recording part 24b of the facsimile B in such a manner, the picture having an optimum proper density is obtained. Therefore, the need to correct the density of reception data at each time is reduced.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an image transmitting/receiving device and an image transmitting/receiving method, such as a facsimile, for transmitting and receiving image data.

[Conventional technology]

2. Description of the Related Art In recent years, with advances in image recording equipment and communication technology, facsimile devices that transmit and receive images are rapidly becoming popular. In the image recording section of a facsimile machine, the received image is digitally recorded by a recording head using inkjet or thermal transfer, but it is difficult to manufacture these recording heads without any variation, and it is difficult to manufacture these recording heads without any correction. When recording, variations in image density occur due to variations in the head. For this reason, an inconvenience arises in that the image becomes darker when received by one facsimile machine, and becomes lighter when received by another facsimile machine. A possible configuration of a facsimile machine that takes countermeasures against this problem into consideration will be described below with reference to FIG. 6. The image signals read by the image reading sections 21a and 21b are subjected to image processing such as logarithmic transformation in the image processing sections 22a and 22b. The density correction units 23a and 23b have a slope of, for example, 08 to 1.
In the look-up table of 41 straight lines that change in increments of 0.01 between 2 and 2, straight lines are selected according to the density of the head of the image recording section. For example, straight line A in FIG. 7 is a standard straight line with a slope of 1.0, but if the density of the head is high, straight line B with a smaller slope is selected. As a result, when the signal S is input, the output becomes S-ΔS S-ΔS, which is reduced by a factor of eight, so that the image density signal is corrected. For example, when transmitting an image from facsimile A to facsimile B, the output of the image processing section 22a of facsimile A is transmitted to facsimile B and input to the density correction section 23b of facsimile B. Then, density correction is performed in accordance with the head of facsimile B, and even facsimile B can obtain an image with appropriate density.

[Problem to be solved by the invention]

However, in the conventional example described above, since correction is performed by table conversion on the receiving side, it is necessary to transmit and receive multivalued image data, which has the problem of increasing the time and cost of transmitting and receiving.

[Means to solve the problem]

The present invention has been made in view of the above problems, aims to solve the above problems, and has the following configuration as a means for achieving the object. That is, the image transmitting device includes a data output means for outputting m (>2) value image data to be transmitted to a receiving side that performs image recording using a recording head composed of a plurality of image recording elements, and an output from the data output means. a density correction unit that performs density correction processing on the m-value image data based on recording density correction data of the recording head on the receiving side; )
The apparatus includes a converting means for converting into value image data, and a transmitting means for transmitting the n-value image data converted by the converting means to the receiving side. Alternatively, the image transmitting/receiving device may include a data output means for outputting m (>2) value image data to be transmitted to a receiving side where image recording is performed by a recording head consisting of a plurality of image recording elements, and data received by the receiving means. a storage means for storing recording density correction data stored in the recording means; a density correction means for performing density correction processing on m-value image data output from the data output means based on the recording density correction data stored in the recording means; Conversion means for converting m-value image data subjected to density correction processing by the density correction means into n-value image data (<m); and transmission for transmitting the n-value image data converted by the conversion means to a receiving side. and means. Furthermore, the image transmitting and receiving device includes a recording means for recording an image using a recording head composed of a plurality of image recording elements, a transmitting means for transmitting recording density correction data of the recording head of the recording means to a transmitting side, and a transmitting means for transmitting recording density correction data of the recording head of the recording means. and a receiving means for correcting image data of m (>2) value on the transmitting side based on the transmitted recording density correction data and receiving the image data transmitted as n (<m) value.

[Effect]

In the above configuration, since the image transmitting device has means for performing density correction according to correction data for correcting the recording density of the recording head of the image receiving device, images of appropriate density can be transmitted and received by transmitting and receiving a small amount of information.

[Embodiment] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment] First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. In FIG. 1, the same components as in FIG. 6 are given the same numbers. In the figure, facsimiles A and B each have a reading section 21a,
21b, image processing units 22a, 22b, density correction ROM3
1a, 31b, density correction RAM 32a, 32b, backup RAM 33a. 33b, binarization processing units 34a, 34b, interfaces 35a, 35b, and image recording unit 24a. 24b. In this embodiment, the density correction ROMs 31a and 31b are ROMs that store lookup tables on 64 straight lines whose slopes differ by 0.01 between 0.68 and 1.31, and the density correction RAMs 32a and 32b is a RAM that stores data on which slope to select. Further, the image recording units 24a and 24b are multi-nozzle inkjet printers with 256 nozzles. The operation of the facsimile apparatus of this embodiment having the above configuration will be explained below with reference to the flowchart of FIG. The following description will be made using an example in which image data is transmitted from facsimile A to facsimile B, and the received image is recorded by facsimile B. First, in step Sl, facsimile A calls facsimile B. When facsimile B responds and a mutual communication path is established, the process advances to step S2, where facsimile A sends a transmission start signal to B. And step S3
Then, the facsimile A backs up the contents of the density correction RAM 32a to the backup RAM 33a. On the other hand, facsimile B, which has received the transmission start signal from facsimile A, stores the density correction RAM 3 in step S4.
2b is sent to facsimile A via interface 35b. The facsimile A, which receives the contents of the density correction RAM 32b from the facsimile B via the interface 35a, stores the contents in the correction data RAM 32a in step S5. Now that you are ready to send the image, send fax A.
reads the transmission document from the reading section 21a in step S7,
The read image signal is processed by the image processing section 2 in the subsequent step S8.
The image is processed in step 2a and sent to the density correction ROM 31a. The density correction ROM 31a performs the density correction R in step S9.
The slope of the straight line is selected according to the signal from the AM 32a, and density correction is performed. In this embodiment, the image recording section 24b has two
This is a multi-nozzle inkjet printer with 56 nozzles, and the optimum inclination according to the density of this head may be stored as correction data. Note that the data for one head is 6 bits because it indicates which of the 64 types of correction straight lines is to be used. Here, the density correction RAM 32 a includes step S
5, data for correcting the density of the image recording head of the image recording section 24b of the facsimile B is received and stored, and a correction straight line in the density correction ROM 31a is selected. The density-corrected image data is processed by the dither method in step S10.
The binarization processing unit 3 uses a known binarization method such as the error diffusion method.
It is binarized at 4a. Subsequently, the binarized image data is sent to the facsimile B side via the interface 35a in step Sll. Then, in step S12, the interface 35
The image is sent to the image recording section 24b of facsimile B via b, and the image is recorded. Since the image data sent to facsimile B has been density-corrected in accordance with the image recording section 24b of facsimile B, an image with optimally corrected density can be obtained. For this reason, the need to correct the density of each received data is reduced. Even though an 8-bit A4 image is sent and received at 400DPI, it is necessary to send and receive 8-bit data as is and perform unevenness correction as described in the conventional example. In this case, it was necessary to send and receive information of approximately 1.24 x 10" bits, but in this example, unevenness correction data of 6 bits and binary image data of 15466839 bits were transmitted and received.
By simply transmitting and receiving information of about 1.55 x 10' bits in total, images of appropriate density can be transmitted and received, which has the advantage of greatly reducing time and cost.

[Second Embodiment] Next, another embodiment according to the present invention will be described. Although the above-mentioned first embodiment describes the case of a monochrome image, the present invention is not limited to monochrome images, and FIG. 3 shows an example in which the present invention is applied to a color image. The basic block configuration is the same as the first embodiment described above, but the reading section has a sensor that outputs three color separation signals of R, G, and B, and the image processing section performs logarithmic conversion, masking, It performs UCR processing. The density correction ROM is the same as that in the first embodiment shown in FIG. 1, but the density correction RAM stores density correction data for each of the four heads of cyan, magenta, yellow, and black. The binarization processing section is the same as in the first embodiment, but the image recording sections 54a and 54b are color image recording sections having four heads of cyan, macenta, yellow, and black, and each head has 256 nozzles. It is an ink sheet head. In the second embodiment having the above configuration, by performing the same operation as in the first embodiment shown in FIG. Density correction can be performed in accordance with the density correction data. In the case of a color image as in the second embodiment, variations in the density of the recording heads of each color appear as variations not only in density but also in tint, so it is important to adjust the density balance of the recording heads of each color. The advantage of having the configuration of the embodiment is great.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 3, the same numbers as in FIG. 1 indicate the same components. In the third embodiment, block 40a,
At 40b, after the image data is binarized, the data is compressed, and the compressed data is transmitted and received. For this reason,
It becomes possible to transmit and receive images with appropriate density by transmitting and receiving even less data.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described. In each of the embodiments described above, a straight line as shown in FIG. 7 is used as the density correction ROM table, but the relationship between the input signal and the image density is often non-linear as shown in FIG. 4. In such a case, it is impossible to correct the density across all gradations simply by correcting the slope of the straight line. The fourth embodiment improves this point, and the density correction RO
This uses a nonlinear curve for the M table. FIG. 5 shows the curves of the density correction ROM table used in this embodiment, and 64 nonlinear curves are prepared. Each curve corrects the gradation characteristics when the size of the dots differs little by little, and is obtained through experiments or simulations. With the above table configuration, and by selecting the optimal curve according to the density correction data of each head, as in the first to third embodiments described above, it is possible to transmit and receive images with appropriate density across all gradations. can. [Fifth Embodiment] Next, a fifth embodiment of the present invention will be described. In the previous embodiment, the characteristic data of the recording head on the receiving side was transmitted from the receiving side to the transmitting side. In the fifth embodiment, the correction data RAMs 32a and 32b shown in the block diagram of FIG. 1 are constituted by a removable IC cart, and the characteristic data of the recording head on the receiving side is stored in this IC card. By storing the characteristic data in the IC cart on the receiving side and sending it to the transmitting side by mail or the like, it is possible to eliminate the need to transmit the characteristic data from the receiving side to the transmitting side. In the above embodiments, facsimile communication using a facsimile machine was given as an example, but communication does not necessarily need to be carried out using a telephone line. The present invention can also be implemented when only devices are connected. Further, the head of the image recording section is not limited to an inkjet head, and the present invention can be similarly carried out as long as it is a multi-head having a plurality of image recording elements, such as thermal transfer or electrostatic recording. Further, the image communication section does not necessarily have to include an image reading section, and may be one that transmits graphic data or the like from a computer. Furthermore, in the above embodiments, image data that has been binarized after density correction is transmitted, but the present invention is not limited to this, and it is also possible to transmit further compressed data after binarization processing. You can. Furthermore, in addition to the binarization process, an n-value process may be performed in an image transmitting/receiving system that performs multi-tone recording. Among inkjet recording methods, the present invention particularly relates to an inkjet recording method proposed by Canon Co., Ltd. in which flying droplets are formed and recorded using thermal energy, a so-called bar blue jet recording head, and a recording apparatus. It brings about excellent effects. Typical configurations and principles thereof are disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796, and the present invention is preferably carried out using these basic principles. This recording method is applicable to both so-called on-demand type and continuous type. To briefly explain this recording method, an electrothermal transducer placed corresponding to the sheet holding the liquid (ink) or the liquid path causes the liquid (ink) to boil in accordance with the recorded information. Thermal energy is generated to cause film boiling on the thermally active surface of the recording head by applying at least one drive signal to provide a rapid temperature rise such that film boiling occurs. In this way, bubbles can be formed in one-to-one correspondence with the drive signals applied from the liquid (ink) to the electrothermal transducer, which is particularly effective for on-demand recording methods. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection hole to form at least one drop. When this drive signal is in the form of a pulse, bubble growth and contraction occurs immediately and appropriately, and liquid (ink) ejection with particularly excellent responsiveness can be achieved, which is more preferable. This pulse-shaped drive signal is described in US Pat. No. 44,633.
Those described in Japanese Patent No. 59 and Japanese Patent No. 4,345,262 are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed. In addition to the configuration of the recording head that combines ejection holes, liquid flow paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, US Pat. No. 4,558,333, US Pat. No. 44,596
As disclosed in the specification of No. 00, the present invention also includes a structure in which a heat acting part is arranged in a bending region. In addition, for a plurality of electrothermal converters, a common slit is used as a discharge hole of the electrothermal converter, which is disclosed in Japanese Patent Application Laid-Open No. 123670 of 1981, and an aperture that absorbs pressure waves of thermal energy. The present invention is also effective in a configuration based on Japanese Unexamined Patent Application Publication No. 138461 of 1983, which discloses a configuration compatible with a discharge section. Furthermore, the recording head to which the present invention can be effectively utilized includes:
There is a full-line type recording head that has a length corresponding to the maximum width of a recording medium that can be recorded by a recording apparatus. This full-line head may be a full-line configuration obtained by combining a plurality of recording heads as disclosed in the above-mentioned specification, or a single full-line recording head formed integrally. In addition, a replaceable chip-type recording head that is attached to the device body enables electrical connection to the device body and ink supply from the device body, or a chip type recording head that is installed integrally with the recording head itself. The present invention is also effective when using a cartridge type recording head. Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc. to the recording apparatus of the present invention, since this can make the recording apparatus of the present invention even more stable. Specifically, these include preheating of the recording head using a capping means, a cleaning means, a pressurizing or suction means, an electrothermal converter or a separate heating element, or a combination thereof. It is also effective to add a means for performing a preliminary ejection mode that performs ejection other than printing, in order to perform stable printing. Furthermore, the recording mode of the recording device is not limited to a moat that stores only mainstream colors such as black, but may also be one in which the recording head is configured integrally or a configuration in which a plurality of recording heads are combined. The present invention is also extremely effective for devices equipped with at least one of a subcolor or a full color by color mixture. Although the embodiments of the present invention described above are explained using liquid ink, the present invention can also use ink that is solid at room temperature or ink that is soft at room temperature. be able to. In the above-mentioned inkjet devices, the temperature of the ink itself is generally adjusted within the range of 30°C to 70°C to keep the viscosity of the ink within a stable ejection range. It is good if the ink is liquid. In addition, excessive temperature rise of the head and ink due to thermal energy can be actively prevented by using energy to change the state of the ink from a solid state to a liquid state, or it can be left unattended for the purpose of preventing ink evaporation. It is also possible to use an ink that hardens with water. In any case, the ink may liquefy by applying thermal energy in accordance with the recording signal and be ejected as liquid ink, or it may already begin to solidify by the time it reaches the recording medium. It is also applicable to the present invention to use an ink that has the property of Such ink is held as a liquid or solid in the recesses or through holes of a porous sheet, as described in JP-A-54-56847 or JP-A-60-71260. It may also be configured to face the electrothermal converter. In the present invention, the most effective method for each of the above-mentioned inks is one that implements the above-mentioned film boiling method.

【Effect of the invention】

As described above, according to the present invention, it is now possible to transmit and receive images with appropriate density by transmitting and receiving a small amount of information.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the first and second embodiments according to the present invention, FIG. 2 is a flowchart showing the facsimile communication operation in this embodiment, and FIG. 3 is a block diagram showing the configuration of the third embodiment according to the present invention. FIG. 4 is a diagram showing the relationship between the input signal and image density; FIG. 5 is a diagram showing the density correction table of the fourth embodiment according to the present invention; FIG. 6 is a diagram showing the density correction table of a conventional facsimile machine. A block diagram showing the configuration, FIG. 7 is a diagram showing an example of a density correction table. In the figure, 21...reading unit, 22...image processing unit, 24
. . . Image recording unit, 31 . . . Density correction ROM, 32.
...Density correction RAM, 34...Binarization processing section, 35.
. . . Interface, 40 . . . Binarization and compression processing unit. Figure 2 Figure 7, 4a3 @! lI! PiE;gu guest stab

Claims (10)

[Claims] (1) Data output means for outputting m (>2) value image data to be transmitted to a receiving side where image recording is performed by a recording head consisting of a plurality of image recording elements; and m-value image data,
a density correction unit that performs density correction processing based on recording density correction data of the recording head on the receiving side; An image transmitting apparatus comprising: a converting means for converting; and a transmitting means for transmitting n-value image data converted by the converting means to the receiving side. (2) Claim 1 further comprising a storage means for storing recording density correction data of the recording head on the receiving side.
The image transmitting device described in . (3) data output means for outputting m (>2) value image data to be transmitted to a receiving side where image recording is performed by a recording head consisting of a plurality of image recording elements; storage means for storing the recording density correction data stored in the recording means; and density correction means for performing density correction processing on m-value image data output from the data output means based on the recording density correction data stored in the recording means. , conversion means for converting the m-value image data subjected to the density correction process by the density correction means into n-value image data (<m); and converting the n-value image data converted by the conversion means into n-value image data. An image transmitting/receiving device comprising: a transmitting means for transmitting to the receiving side. (4) The image transmitting and receiving apparatus according to claim 3, wherein the image to be transmitted and received is a color image. (5) The image transmitting/receiving apparatus according to claim 3, wherein the converting means converts m-value image data into binary image data. (6) The image transmitting/receiving apparatus according to claim 3, wherein the data output means reads the original image and outputs m-value image data. (7) The image transmitting/receiving apparatus according to claim 3, wherein the recording head is an inkjet recording head that performs recording by ejecting ink. (8) The recording head has a plurality of ejection ports for ejecting ink, and the image recording element is provided for each corresponding ejection port to cause a state change in the ink due to heat, and to generate an ink flow based on the state change. 4. The image transmitting/receiving apparatus according to claim 3, wherein the image transmitting/receiving apparatus is a thermal energy generator that causes the liquid to be ejected from the ejection port to form flying droplets. (9) a recording means for recording an image by a recording head comprising a plurality of image recording elements; a transmitting means for transmitting recording density correction data of the recording head of the recording means to a transmitting side; and a transmitting means by the transmitting means. and receiving means for correcting image data of m (>2) values on the sending side based on the transmitted recording density correction data and receiving image data transmitted as n (<m) values. An image transmitting/receiving device characterized by: (10) Image data of m(>2) value to be transmitted is transferred to n(<
m) A transmitting side that converts it into value image data and transmits it, and a receiving side that receives the n-value image data transmitted from the transmitting side and records the image with a recording head consisting of a plurality of image recording elements. In the image transmission and reception method between the transmitting side performs density correction processing on the m-value image data and transmits it to the receiving side as the n-value image data, and receives the n-value image data transmitted from the transmitting side;
An image transmission/reception method characterized in that the receiving side records an image using the recording head.