JP3143466B2 - Image recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head and an image recording apparatus using the recording head.

[Conventional technology]

2. Description of the Related Art Conventionally, as an example of an apparatus using this kind of multihead, there is an apparatus that converts read image data into a digital signal, performs data processing, and then forms an image using the multihead. However, such an apparatus has not been free from the problem that unevenness in density occurs in an output image due to characteristic variations due to a multi-head manufacturing process and characteristic variations of constituent materials.

Therefore, a storage means for storing correction data corresponding to the output characteristics of each head of the multi-head array and a means for correcting input image data based on the stored data are provided. A device has been proposed.

[Problems to be solved by the invention]

However, in the above proposed example, density unevenness correction data such as multi-head variation cannot be stored in the multi-head. For this reason, this correction data has been created in an independent ROM or the like separate from the multihead. However, the correction data itself is different for each multihead,
Even though the correction data is unique to each multihead and is valid only for a specific multihead, there is a possibility that the ROM and the multihead may be incorrectly combined in some cases. was there.

In addition, it is necessary to always supply the multi-head and the ROM as a pair, for example, to the user. In addition, a great deal of work is required in the production management of the multi-head and when exchanging the multi-head. In addition, there was also a problem in cost.

In addition, in order to ensure reliability, such a head is made into a disposable type cartridge type that can be attached to and detached from the carriage, and is often replaced.In such a case, the above-described correction of the density unevenness is performed by individual heads. Since it is necessary to make them different, the adjustment operation is complicated and difficult.

Further, in such a disposable head, there is a problem that it is difficult to detect the replacement satisfactorily irrespective of the unevenness correction described above.

An object of the present invention is to provide a recording head capable of solving each or all of the above-described problems and an image recording apparatus using the recording head.

Another object of the present invention is to provide an apparatus which can reduce printing unevenness due to a recording head even when the recording head is replaced.

Still another object of the present invention is to provide an image recording apparatus capable of reducing the cost by eliminating the waste of the configuration.

It is another object of the present invention to provide an image four-green apparatus capable of stably obtaining a good recorded image even with aging.

Still another object of the present invention is to provide a recording head having a novel function and / or an image recording apparatus using the recording head.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples. In the following embodiments, an image forming apparatus using an ink jet recording direction will be described. In such an ink jet recording, a head having a multi-nozzle provided with a plurality of nozzles for ejecting ink will be described as an example of the multi-head.

First, the configuration of a digital color copying machine will be described as a reference example.

FIG. 1 is a cross-sectional view of a digital color copying machine of a reference example.

 The whole can be divided into two parts.

The upper part of FIG. 1 is a color image scanner 1 for reading a document image and outputting digital color image data.
(Hereinafter, abbreviated as a scanner unit 1), and a control unit 2 which is built in the scanner unit 1 and performs various image processing of digital color image data and has a processing function such as an interface with an external device. .

The scanner unit 1 reads a three-dimensional object and a sheet document placed below the document holder 11 and also has a built-in mechanism for reading a large-size sheet document.

The operation unit 10 is connected to the controller unit 2 and is used to input various information as a copier. The controller unit 2 instructs the scanner unit 1 and the printer unit 3 on operations according to the input information.
Further, when a complicated editing process needs to be performed, a digitizer or the like is attached in place of the document presser 11, and this is connected to the controller unit 2, thereby enabling advanced processing.

The lower part of FIG. 1 shows a printer unit 3 for recording a color digital image signal output from the controller unit 2 on recording paper. In this embodiment, the printer unit 3 is a full-color ink jet printer using an ink jet recording head described in Japanese Patent Application Laid-Open No. 54-59936.
It is a printer.

The two parts described above are separable and can be installed at remote locations by extending the connecting cable.

(Printer Unit) FIG. 2 is a cross-sectional view of the digital color copying machine of FIG. 1 as viewed from the side.

First, an exposure lamp 14, a lens 15, and an image sensor 16 capable of reading a full-color line image
The original image placed on the original platen glass 17, the projected image by the projector, or the sheet original image by the sheet feed mechanism 12 is read by the CCD (in the present embodiment). next,
Various types of image processing are performed by the scanner unit 1 and the controller unit 2 and are recorded on recording paper by the printer unit 3.

In FIG. 2, the recording paper is composed of a paper feed cassette 20 for storing cut paper of a small fixed size (in this embodiment, A4 to A3 size) and a large size (in this embodiment, A2 to A1 size). It is supplied from a roll paper 29 for performing.

In addition, by feeding recording paper one sheet at a time from the manual feed slot 22 in FIG. 1 along the paper feed unit cover 21, paper feeding from outside the apparatus = manual feeding is also possible.

The pick-up roller 24 is a roller for feeding cut paper one by one from the paper feed cassette 20. The fed cut paper is conveyed to the first paper feed roller 26 by the cut paper feed roller 25. You.

The roll paper 29 is sent out by a roll paper feed roller 30, cut into a fixed length by a cutter 31, and conveyed to a first feed roller 26.

Similarly, the recording paper inserted from the manual feed port 22 is conveyed to the first paper feed roller 26 by the manual feed roller 32.

Pick-up roller 24, cut paper feed roller 25,
The roll paper feed roller 30, the first feed roller 26, and the manual feed roller 32 are provided with a not-shown paper feed motor (in this embodiment, a DC servo motor).
(Using a motor), and an on / off control can be performed at any time by an electromagnetic clutch attached to each roller.

When the printing operation is started by an instruction from the controller unit 2, the recording paper selected and fed from any of the above-described paper feeding paths is transported to the first paper feeding roller 26. In order to remove the skew of the recording paper, a first paper feed roller 26 is turned on after a predetermined amount of paper loop is formed, and the recording paper is conveyed to a second paper feed roller 27.

Between the first paper feed roller 26 and the second paper feed roller 27, the recording paper is slacked by a predetermined amount in order to perform accurate paper feed operation between the paper feed roller 28 and the second paper feed roller 27. Create The buffer amount detection sensor 33 is a sensor for detecting the buffer amount. By always making a buffer during paper transport, the load on the paper feed roller 28 and the paper feed second roller 27 can be reduced, especially when large-size recording paper is transported, and accurate paper feed operation is possible. Become.

When printing with the recording head 37, the recording head 37
The scanning carriage 34 on which the etc. are mounted is the carriage rail
A reciprocating scan is performed on the scan 36 by a scan motor 35. In the forward scan, an image is printed on the recording paper, and in the backward scan, an operation of feeding the recording paper by a predetermined amount by the paper feed roller 28 is performed. At this time, while the drive system is being detected by the buffer amount detection sensor 33 by the paper feed motor, control is performed so that a predetermined buffer amount is always obtained.

The printed recording paper is discharged to the paper discharge tray 23 and the printing operation is completed.

Next, the details around the scanning carriage 34 will be described with reference to FIG.

In FIG. 3, a paper feed motor 40 is a drive source for intermittently feeding recording paper, and drives the second paper feed roller 27 via a paper feed roller 28 and a second paper feed roller clutch 43.

The scanning motor 35 is a driving source for scanning the scanning carriage 34 in the directions of arrows A and B via the scanning belt 34. In this embodiment, a pulse motor is used for the paper feed motor 40 and the scanning motor 35 because accurate paper feed control is required.

When the recording paper reaches the second paper feed roller 27, the second paper feed roller clutch 43 and the paper feed motor 40 are turned on, and the recording paper is conveyed on the platen 39 to the paper feed roller 28.

The recording paper is detected by a paper detection sensor 44 provided on the platen 39, and the sensor information is used for position control, jam control, and the like.

When the recording paper reaches the paper feed roller 28, the paper feed second roller clutch 43 and the paper feed motor 40 are turned off and the platen 39 is turned off.
Suction operation is performed from the inside by a suction motor (not shown),
The recording machine is brought into close contact with the platen 39.

Prior to the image recording operation on the recording machine, the scanning carriage 34 is moved to the position of the home position sensor 41, and then the backward scanning is performed in the direction of arrow A, and cyan, magenta, yellow, and black are read from predetermined positions. Is ejected from the recording head 37 to perform image recording. When the image recording for a predetermined length is completed, the scanning carriage 34 is stopped, and the backward scanning is started in the direction of arrow B, and the home position sensor is started.
The scanning carriage 34 is returned to the position 41. During the return scan,
The paper feed motor feeds paper for the length recorded by the recording head 37.
The operation is performed in the direction of arrow C by driving the paper feed roller 28 by 40.

In this embodiment, the recording head 37 is an ink jet nozzle of a type in which bubbles are formed by heat and ink droplets are ejected at the pressure, and four recording nozzles each having 256 nozzles are used. ing.

When the scanning carriage 34 stops at the home position detected by the home position sensor 41, the recovery operation of the recording head 37 is performed. This is a process for performing a stable printing operation, and in order to prevent unevenness at the start of ejection due to a change in viscosity of ink remaining in the nozzles of the printing head 37, the feeding time, the internal temperature of the apparatus, and the like. Recording head 37 according to pre-programmed conditions such as
This is a process of performing a pressurizing operation, an idle discharge operation of ink, and the like.

The image recording is performed on the entire surface of the recording paper by repeating the operation described above.

(Scanner Unit) Next, the operation of the scanner unit 1 will be described with reference to FIGS.

FIG. 4 is a view for explaining a mechanical mechanism inside the scanner section 1. FIG.

The CCD unit 18 is a unit composed of a CCD 16, a lens 15, etc., and has a main scanning motor 5 fixed on a rail 54.
The image forming apparatus moves on the rails 54 by a driving system including a pulley 51, a pulley 52, a pulley 52, and a wire 53 in the main scanning direction, and reads an image on the platen glass 17 in the main scanning direction. The light-shielding plate 55 and the home position sensor 56 are used for position control when the CCD unit 18 is moved to the main scanning home position in the correction area 68 shown in the figure.

The rail 54 rests on rails 65 and 69, the sub-scanning motor 60, pulleys 67, 68, 71, 76, shafts 72, 73, and wires 66, 70.
It is moved by a drive system in the sub-scanning direction. Shade plate
57, the home position sensors 58 and 59 are provided with rails for the home position of each sub-scan in the book mode for reading an original such as a book placed on the platen glass 17 and in the sheet mode for reading the sheet. Used for position control when moving 54.

The sheet feed motor 61, the sheet feed rollers 74 and 75, the pulleys 62 and 64, and the wire 63 are mechanisms for feeding a sheet document. This mechanism is a mechanism for feeding a sheet document placed on the document table glass 17 and placed downward by the sheet feed rollers 74 and 75 by a predetermined amount.

FIG. 5 is an explanatory diagram of a reading operation in the book mode and the sheet mode.

In the book mode, the CCD unit 18 is moved to the book mode home position (book mode HP) shown in the correction area 68 in FIG. The reading operation of the entire surface is started.

Prior to scanning of the document, data necessary for processes such as shading correction, black level correction, and color correction are set in the correction area 68. Thereafter, the main scanning motor 50 starts scanning in the main scanning direction in the direction of the arrow shown in the figure. When the reading operation of the area indicated by is completed, the main scanning motor 50 is rotated in the reverse direction and the sub-scanning motor 60 is driven to move the correction area 68 of the area in the sub-scanning direction. continue,
As in the case of the main scanning of the area, processing such as shading correction, black level correction, and color correction is performed as necessary, and the area is read.

By repeating the above scanning, the reading operation of the entire area is performed. After the reading operation of the area is completed, the CCD unit 18 is again switched to the book mode home mode.
Return to position.

In the present embodiment, the platen glass 17 can actually read a document having a maximum size of A2.In practice, however, it is necessary to perform a larger number of scans.However, in the present description, the operation is simplified for easy understanding of the operation. .

In the sheet mode, the CCD unit 18 is moved to the illustrated sheet mode home position (sheet mode HP).
Move to the area of the sheet original and feed the sheet feed motor
Scanning is repeated while the 61 is intermittently operated, and the entire sheet document is scanned.

Prior to the scanning of the document, processing such as shading correction, black level correction, and color correction is performed in the correction area 68, and then scanning in the main scanning direction is started by the main scanning motor 50 in the direction of the arrow shown in the figure. When the reading operation on the forward path in the area is completed, the main scanning motor 50 is rotated in the reverse direction, and the sheet feed motor 61 is driven during the scanning on the backward path to move the sheet document by a predetermined amount in the sub-scanning direction. Subsequently, the same operation is repeated to read the entire surface of the sheet document.

Assuming that the above-described reading operation is an equal-magnification reading operation, the area that can be read by the CCD unit 18 is actually a large area as shown in FIG. This is because the digital color copying machine of the present embodiment has a magnification / reduction function. That is, since the area recordable by the recording head 37 is fixed to 256 bits at a time as described above, for example, when a 50% reduction operation is performed, the image information of the area of at least twice the 512-bit area is reduced. It is necessary. Therefore, the scanner unit 1 has a function of reading and outputting image information of an arbitrary image area by one main scanning reading.

(Film Projection System) The scanner unit 1 of this embodiment can be equipped with a projection exposure unit for projecting a film.

FIG. 6 is a perspective view when a projection unit 81 and a reflection mirror 80 as projection exposure means are attached to the scanner unit 1. FIG.

The projector unit 81 is a projector for projecting a negative film and a positive film, and the film is held by a film holder 82 and mounted on the projector unit 81. The image projected from the projector unit 81 is reflected by the reflection mirror 80 and reaches the Fresnel lens 83. The Fresnel lens 83 converts this image into parallel light and forms an image on the platen glass 17.

Thus, negative film and positive film images are
Since an image is formed on the platen glass 17 by the projector unit 81, the reflection mirror 80, and the Fresnel lens 83, the image can be read by the CCD unit 18 in the same manner as the reflection original.

FIG. 7 is a diagram for explaining the film projection system in more detail.

Projector Unit 81 is a halogen lamp 90,
It comprises a reflecting plate 89, a condenser lens 91, a film holder 82, and a projection lens 92. The direct light emitted by the halogen lamp 90 and the reflected light by the reflector 89 are condensed by the condenser lens 91 and reach the window of the film holder 82. The film holder 82 has a window slightly larger than one frame of the negative film and the positive film so that the film can be mounted with a margin.

The projection light reaching the window of the film holder 82 is transmitted through the film mounted therein to obtain a projection image of the film. The projection image obtained in this way is
After being optically enlarged by 92 and turned by the reflection mirror 80, it is converted by the Fresnel lens 83 into a parallel light image.

This image is read by the CCD unit 18 inside the scanner 1 in the block mode described above and converted into a video signal.

FIG. 8 is a diagram showing an example of the relationship between a film and a projected image formed on a platen glass.

This shows a state in which a 22 × 34 mm film image is magnified 8 times and formed on the platen glass 17.

(Explanation of Entire Function Block) Next, the function block of the digital color copying machine of this embodiment will be described with reference to FIG.

The control units 102, 111, and 121 are control circuits that control the scanner unit 1, the controller unit 2, and the printer unit 3, respectively, and include a micro computer, a program ROM, a data memory, a communication circuit, and the like. Control units 102-111
The control units 111 and 121 are connected to each other by a communication line, and employ a so-called master-slave control mode in which the control units 102 and 121 operate according to instructions from the control unit 111.

When operating as a color copier, the control unit 111 operates according to input instructions from the operation unit 10 and the digitizer 114.

As shown in FIG. 6, the operation unit 10 uses, for example, a liquid crystal (LCD display unit 84) as a display unit and has a touch panel made of a transparent electrode on the surface thereof.
Selection instructions such as designation of colors and designation of editing operation can be performed. Keys related to the operation, for example, a start key 87 for instructing the start of a copy operation, a stop key 88 for instructing a stop of a copy operation, a reset key 89 for returning the operation mode to a standard state, and a projector key for selecting a projector.
Frequently used keys such as the key 86 are provided independently.

The digitizer 114 is for inputting position information necessary for trimming, masking processing and the like, and is connected as an option when complicated editing processing is required.

The control unit 111 also controls a general-purpose parallel interface control circuit such as IEEE-488, a so-called GP-IB interface, and the like, and controls the I / F control unit 112, and inputs and outputs image data between external devices. Remote control by an external device can be performed through this interface.

Further, the control unit 111 also controls a multi-value synthesizing unit 106, an image processing unit 107, a binarization processing unit 108, a binary synthesizing unit 109, and a buffer memory 110 which perform various kinds of processing relating to the image.

The control unit 102 controls the mechanical driving unit 105 that controls the mechanism of the scanner unit 1 described above, the exposure control unit 103 that controls the exposure of the lamp when reading a reflected original, and the halogen lamp when the projector is used. The control of the exposure control unit 104 that performs the exposure control of 90 is performed. The control unit 102 also controls the analog signal processing unit 100 and the input image processing unit 101 that perform various types of processing related to images.

The control unit 121 controls the mechanism driving unit 105 for controlling the mechanism of the printer unit 3 described above, and absorbs the time variation of the mechanical operation of the printer unit 3 and corrects the delay due to the arrangement of the recording heads 117 to 120 on the mechanism. The synchronization delay memory 115 is controlled.

Next, the image processing block of FIG. 9 will be described in detail along the flow of images.

The image formed on the CCD 16 is converted into an analog electric signal by the CCD 16. The converted image information is red → green →
Analog signal processing unit 100 processed serially like blue
Is input to In the analog signal processing unit 100, red, green,
After performing sample & hold, dark level correction, dynamic range control, etc. for each blue color, analog-to-digital conversion (A / D conversion) is performed, and serial multivalued (8-bit length for each color in this embodiment) ), And outputs the digital image signal to the input image processing unit 101.

The input image processing unit 101 similarly performs necessary correction processing in a reading system such as CCD correction and γ correction as a serial multi-valued digital image signal.

The multi-value synthesizing unit 106 of the controller unit 2 includes the scanner unit 1
This is a circuit block for selecting a serial multi-valued digital image signal sent from it and a serial multi-valued digital image signal sent via a parallel I / F, and performing a synthesizing process. The selectively synthesized image data is sent to the image processing unit 107 as a serial multivalued digital image signal.

The image processing unit 107 performs smoothing processing, edge enhancement,
This circuit performs black extraction, masking processing for color correction of recording ink used in the recording heads 117 to 120, and the like. The serial multi-valued digital image signal output is output to the binarization processing unit 10
8. The data is input to the buffer memory 110, respectively.

The binarization processing unit 108 is a circuit for binarizing a serial multi-valued digital image signal, and can select a simple binary with a fixed slice level, a pseudo halftone process with a dither method, or the like. Here, the serial multi-valued digital image signal is converted into a 4-color binary parallel image signal.
Image data of four colors is sent to the binary synthesizing unit 109, and image data of three colors is sent to the buffer memory 110.

The binary synthesizing unit 109 selects a three-color binary parallel image signal sent from the buffer memory 110 and a four-color binary parallel image signal sent from the binarization processing unit 108.
This is a circuit for synthesizing a binary parallel image signal of four colors.

The buffer memory 110 is a buffer memory for inputting / outputting a multi-valued image and a binary image via a parallel I / F, and has memories for three colors.

The synchronization delay memory 115 of the printer unit 3
Absorption and recording head 117-120
This is a circuit for performing delay correction by the arrangement on the mechanism of
Internally, a timing required for driving the recording head units 117 to 120 is also generated.

The head controllers 301 to 304 are analog driving circuits for driving the recording heads 305 to 308.
308 are generated directly.

As described above, the recording head units 117 to 120 according to the present embodiment are constituted by the head controllers 301 to 304 and the recording heads 305 to 308.
A head drive circuit and an EEPROM (not shown) are built in 301 to 304, and store density unevenness correction data described later. The density unevenness correction data is read and written by the control unit 309, but the normal control unit 309 does not write.

The recording head units 117 to 120 eject cyan, magenta, yellow, and black inks, respectively, and record images on recording paper.

FIG. 10 is an explanatory diagram of the timing of the image between the circuit blocks described in FIG.

The signal BVE is a signal indicating an image effective section for each scan in the main scanning reading operation described with reference to FIG. Signal BV
By outputting E multiple times, full-screen image output is performed.

The signal VE is a signal indicating an effective section of an image read for each line by the CCD 16. Only the signal VE when the signal BVE is valid is valid.

The signal VCK is a clock signal for sending out the image data VD. The signals BVE and VE also change in synchronization with the signal VCK.

The signal HS is a signal used when the signal VE outputs one line, and is valid when the valid and invalid sections are repeated discontinuously. When the signal VE is valid continuously while the one line is output, an unnecessary signal is used. It is. The HS is a signal indicating the start of one-line image output.

Next, rough signal processing in the image processing unit will be described with reference to FIG.

In FIG. 9, a serial (for example, R,
Image data (hereinafter, input image data) input in the order of G and B are sent to the serial / parallel conversion unit 201 and converted into parallel signals of Y (yellow), M (magenta), and C (cyan). Thereafter, it is sent to the masking unit 202 and the selector 203 shown in FIG.

The masking unit 202 is a circuit for correcting the color smear of the output ink, and performs the following calculation.

These nine coefficients are input to the selector unit 203 and the UCR unit 205 as serial signals after correcting the ink smearing in the masking unit 202 determined by the masking control signal from the control unit 200.

The input image data and the image data output from the masking unit 202 are input to the selector 203.

In the selector 203, input image data is selected by a selector control signal 1 sent from the normal control unit 200. When the color correction in the input system is not sufficiently performed, the image data output from the masking unit 202 is selected by the control signal 1 and output. The serial image data output from the selector 203 is input to the black extraction unit 204. In order to set the minimum value of Y, M, C in one pixel as black data, the black extracting unit 204
The minimum value of Y, M, C is detected. The detected black data is input to the UCR unit 205.

The UCR unit 205 subtracts black data extracted from the Y, M, and C signals. The coefficient is simply multiplied for the black data. The black data input to the UCR unit 205 is corrected for a time lag with respect to the image data sent from the masking unit 202, and then the following calculation is performed.

Y ′ = Y−a ₁ Bk M ′ = M−a ₂ Bk C ′ = Ca− ₃ Bk Bk ′ = a ₄ Bk where Y, M, C, and Bk indicate input data of the extraction unit, and Y ′ ,
M ', C', and Bk 'indicate extraction unit output data. Then, the coefficients (a ₁ , a ₂ , a ₃ , a ₄ ) are determined by the UCR control signal sent from the control unit 200.

Then, the data output from the UCR unit 205 is γ,
It is input to the offset unit 206.

In the .gamma., offset section 206, the following tone correction is performed.

Y ′ = b ₁ (Y−C ₁ ) M ′ = b ₂ (M−C ₂ ) C ′ = b ₃ (C−C ₃ ) Bk ′ = b ₄ (Bk−C ₄ ) where Y, M, C, Bk are γ, offset part input data, and Y ′, M ′, C ′, Bk ′ are γ, offset part output data.

Further, the coefficients (b _{1 to} b ₄ , C _{1 to} C ₄ ) in the above equation are determined by the γ and offset control signals sent from the control unit 200.

The signal whose tone has been corrected by the .gamma., offset unit 206 is used as a line buffer 207 for storing image data for the next N lines.
Is input to In this line buffer 207, the control unit 200
According to the memory control signal sent therefrom, the data of five lines necessary for the subsequent smoothing and edge emphasizing unit 208 are output in five lines in parallel. The signals for these five lines are sent to the control unit 200
Is input to a spatial filter having a variable filter size in accordance with the filter control signal from the filter, and smoothing is performed, and then edge enhancement is performed. In the smoothing, as shown in FIG. 12, the noise of the image is removed by using the average value of the target pixel and the peripheral pixels as the density value of the target pixel. The difference between the pixel data of interest and the smoothed signal is used as an edge signal, and edge enhancement is performed by adding the edge signal to the pixel data of interest. Detailed description of the smoothing edge emphasizing unit 208 is omitted.

The image data output from the smoothing / edge enhancement unit 208 is input to a color conversion unit 209, and color conversion is performed by a color conversion control signal from the control unit 200. From the digitizer device 114 in FIG. 9, the color to be converted in advance and the color to be converted,
In addition, an area where the signal is valid is input, and the color conversion unit 209 replaces the image data based on the data. In this embodiment, a detailed description of the color conversion unit 209 is omitted. The image signal output from the smoothing / edge enhancement unit 208 and the image signal after the color conversion are input to the selector 210, and the selector control signal 2 selects the image data to be output. Which image data is selected is determined by specifying a valid area input from the digitizer 114. The image signal selected by the selector 210 is input to the buffer memory 110 and the binarization processing unit 108 in FIG.

Here, the description of the system input to the buffer memory 110 is omitted.

The binarization processing unit 108 will be described. Binarization processing unit 1
The image data input to 08 is the head correction unit 21 in FIG.
Entered into 1. The head correction unit 211 will be described later. The image signal whose density has been corrected by the head correction unit is input to the dither unit 212 in the order of Y, M, C, and Bk in serial 8 bits.

The dither section 212 has a memory space of 6 bits in the main scanning direction, 6 bits in the sub-scanning direction, or 4 bits in the main scanning direction and 8 bits in the sub-scanning section for each color. The dither matrix size is controlled by a dither control signal from the control section 200. , And the dither threshold in the matrix is set. When the dither circuit is operating, the mechanical main scanning direction is the CCD 1 line image reading section signal,
In the sub-scanning direction, the image video clock is counted, and the set dither threshold in the memory space is read. Further, by serially switching the memory space between Y, M, C, and Bk, a serial dither threshold can be obtained. Then this threshold is
The image data inputted to the comparator (not shown) and inputted from the selector 210 is compared with the size.

The output from the comparator is: image data> threshold: 1 image data ≦ threshold: 0. This data is then output to the buffer memory 110 and the binary synthesizing unit 109 in FIG. 9 as parallel 4-bit data in the serial / parallel conversion unit.

Next, the head correcting section 211 will be described with reference to FIGS. 14 and 15. FIG.

FIG. 15 is a schematic diagram of one color of the recording head units 171 to 120. In the present invention, the head for C will be described. Reference numeral 305 denotes a recording head, and 301 denotes a head controller. A connector 310 connects the head controller 301 and the control unit 309. The head controller 301 has a head driver and an EEPROM incorporated therein, and is configured as a hybrid IC.

The EEPROM shown as 265 to 268 in FIG.
This is an EEPROM, which is incorporated one by one corresponding to each color of C, M, Y, K of the head units 171 to 120. Note that IN is an ink supply port and OUT is an ink discharge port.

FIG. 17 shows a modified example of the head shown in FIG. No.
In the modification shown in FIG. 17, since the ink supply port 315 and the ink discharge port 317 are formed integrally with the connector 310, the ink supply port 315 and the ink discharge port 317 can be easily attached to and detached from the image recording apparatus main body.

In FIG. 13, ROMs 265 to 268 are characteristic ROMs in which 256 pieces of measurement information of density unevenness provided in the recording heads of C, M, T, and K are written. Since each of them has 256 lines, data for correcting unevenness in head density corresponding to the number of nozzles is written in the ROMs 265 to 268. VDin is digital image data of Y, M, C, K, Y, M, C, K
Thus, the color component image data for each pixel is input in a dot-sequential manner. Data is extracted from the ROMs 265 to 268 and stored in the selection RAM 260 in accordance with the order of the input image data. 263 is RAM2 for data retrieved from ROMs 265 to 268
A bi-directional buffer for writing to 60.

Reference numeral 259 denotes a selector for selecting either the lower 10 bits or the 10-bit output of the counter 250 from the addresses of the 16-bit address bus output from the CPU 258. RAM260
The selector 259 selects the output of the CPU 258 when writing data into the RAM 260, and selects the output of the counter 250 when reading data from the RAM 260. Reference numeral 262 denotes a correction RAM to which data is written from the CPU 258. Selector 261 is CP
A selector for selecting either the 16-bit address from U or the 8-bit flip-flop 252 and the 8-bit image data input VDin, which is a total of 16 bits, to input to the correction RAM 262. In the correction RAM 262, a correction table as shown by a solid line or dotted lines 1 to 5 in FIG. FIG. 14 shows five types of correction tables indicated by solid lines, but there are many more in the actual correction tables. The above-described correction table of the solid line or the dotted lines 1 to 5 is selected according to data input to the correction RAM 262. That is, when the selector 261 selects the B side, the 8-bit image data input VDin value and the 8-bit head density unevenness correction data are input to the RAM 262, and among them, the 8-bit density unevenness correction data is input. Data is the solid line or dotted line 1-5
Used to select Note that among 1 to 5, the solid line is data at the same magnification and the dotted line is data for zooming, and either the dotted line or the solid line data is written into the correction RAM 262 by the CPU 258 according to the range of nozzles used in the head. It is.

The table written in the correction RAM 262 is written so as to output the correction data ΔA for the input A. The correction data ΔA is temporarily latched by the flip-flop 254 and added to the input image data A by the adder 256. , Are output as the corrected data A + ΔA via the flip-flop 257.

Further, a curve may be used instead of a straight line as the correction table shown in FIG.

In the present reference example, a cubic function is used as a preferable example of such a curve, and since the correction amount of the head unevenness can be suppressed to about ± 15%, the following equation is used so that VDout satisfies the following value. .

Next, the operation of the reference example shown in FIG. 13 corrected as described above will be described.

Before the power of the apparatus is turned on and the copy start key is pressed, the selectors 259 and 261 each select the input on the A side. Accordingly, data from the ROMs 265 to 268 are written in the selection RAM 260 in the order of Y, M, C, and K of the input image data VDin. Further, before the copy start is pressed, the correction table of the dotted line or the solid line in FIG. 14 is written in the correction RAM 262 in accordance with the set magnification.

Next, when the copy start key is pressed and the copying operation starts, the CPU 258 sets the selectors 259 and 261 to the B side, that is, the image control. When the image signal VDin input from the CCD is input to the head correction unit 211, the address output by the counter 250 is input to the address of the selection RAM 260 via the selector 259, and the selection data for each nozzle of each color is flip-flop 252. Through the selector 261. In the selector 261, the 8 bits of the input image signal VDin are set to the lower order, and the output of 8 bits of the selection RAM 260 is set to the upper order, and the correction RA is set.
Input to address A of M262. After that, the correction value according to the above equation is input to the adder 256 via the flip-flop 254 in the correction RAM 262. The image signal VDin is also input to the adder 256 via the flip-flop 255, added to the correction value, realizing the above-described equation, and implementing the above-described equation via the flip-flop 257.
Dout is output from the head correction unit 211. This output is input to the dither unit 212, binarized, and stored in the recording head 37.
Is stored.

In the reference example described with reference to FIG. 13, since the correction ROMs 265 to 268 are provided integrally for each head of Y, M, C, and K, any of the recording head units of C, M, Y, and K can be replaced. Also, new density unevenness correction data can be obtained. Further, since the ROM used in this embodiment is an EEPROM, the stored contents are retained even when the power is turned off. In addition, when the recording head has changed over time due to long-term use, the correction data can be rewritten again, which has the effect of extending the life of the head.

Reference Example (1) Next, a block diagram of a reference example of the present invention will be described with reference to FIG. In the configuration shown in FIG. 13, a 16-bit address is given to the EEPROMs 265 to 268 to read data, but in the configuration shown in FIG. 16, the EEPROM for storing density unevenness correction data is provided. Address, data, etc. are communicated by serial transmission. In the case of serial transmission as in this embodiment, the read / write time of data per byte becomes longer. However, the read / write of correction data does not need to be performed at high speed, and the amount of data to be transmitted / received is 1 byte per multi-head nozzle. There is no problem because it has 256 bytes of correction data.

In FIG. 16, the data serially / parallel converted by the shift register 400 is latched by the latch 401 and
Access M402.

According to this embodiment, there is an effect that the number of signal lines can be reduced. In particular, in the configuration shown in FIG. 3, since the signal lines are bent every time one line is printed, the effect is large in terms of improving reliability.

(2) The storage means for storing density unevenness correction data is EEPROM
However, other storage means, for example, a RAM, may be used. In this case, the same effect can be obtained by supplying power using a lithium battery or the like when the power is turned off.

(3) In addition to the density non-uniformity correction data, information unique to the head, such as a manufacturing lot number, or an optimum driving voltage for each head is slightly different from the storage means. In some cases, the drive voltage of the head is set based on this value.

As described above, according to the present embodiment, by integrating the storage means for storing the density unevenness correction data in the multi-head, it is not necessary to uselessly work, and at the same time, the multi-head does not match the correction ROM. The occurrence of density unevenness is also eliminated, which has the effect of reducing the cost of manufacturing and managing multiheads. In addition, there is an effect that the multihead can be easily replaced and maintenance can be simplified.

Further, in the above-described reference example, since the description has been made using the ink jet recording method, as an example of the multi-head, an apparatus for performing recording by using a multi-nozzle having a plurality of nozzles for ejecting ink is shown, but the present invention is not limited to such an ink jet. The present invention is not limited to an apparatus having a nozzle for ejecting ink, but also an apparatus using another multihead, for example, an apparatus using a multihead provided with a plurality of heating elements for applying heat to perform recording using a thermal transfer recording method. The same applies to the case.

In the above-described reference example, the image data given to each printing element is corrected when the printing condition of the printing element is corrected. However, the present invention is not limited to this. A method of changing power energy may be used. In the case of using an ink jet system in which ink is ejected using air pressure and electrostatic force as a multi-head, for example, the printing condition of each print element is changed by correcting the air pressure and / or electrostatic force described above. You may. The method of correction can be variously modified according to the recording method of the head for image formation.

As described above, according to the present embodiment, by integrating the multi-head and the storage means for storing the correction data for correcting the variation of the multi-head, it is possible to reduce labor and cost when replacing the head. In addition, density unevenness of the multi-head can be reduced.

 Next, another reference example of the present invention will be described.

Other Reference Example 1 FIG. 18 schematically shows an appearance of a main part of an ink jet recording head in another reference example 1. In the figure, 501 is a printed circuit board, 502 is an aluminum radiator plate, 503 is a heater board composed of a heating element and a diode matrix, 504 is an EEPROM (voltage non-volatile memory) for pre-recording density unevenness information, and 505 is a connection with the main body. It is a contact electrode to be a joint part. In addition, the line-shaped discharge port group is not illustrated.

As described above, the EEPROM 504 for recording density non-uniformity information unique to each recording head is mounted on the printed circuit board 501 including the heating element and the drive control unit in the ink jet recording head, and the density of each head is produced during head production. The unevenness is measured, and based on the measured data, the density unevenness data or the data for correcting the unevenness of the density corresponding to each of the outlets or the outlet groups is headed to the EEPROM 504 in units of each outlet or some outlets. Record during production.

In this way, when the recording head is mounted on the main unit, the main unit reads out information on the density unevenness from the recording head, and performs predetermined control for improving the density unevenness based on the information to obtain a high quality image quality. Can be secured.

FIG. 19 shows a main circuit configuration on the printed circuit board 501 of FIG. Here, the circuit configuration inside the heater board 503 is indicated by a dashed line frame.
And an N × M matrix structure of a series connection circuit of a diode 506 for preventing current from flowing. That is,
These heating elements 507 are driven in a time-division manner as shown in FIG. 20, and the supply control of the driving energy is realized by controlling the pulse width (T) on the segment (seg) side.

Reference numeral 504 in FIG. 19 is an example of the EEPROM in FIG. 18, which records density unevenness information according to the present invention. This density unevenness information is output to the main unit by serial communication in response to a request signal (address signal) D1 from the main unit. FIG. 21 shows how the signals are transferred. That is, the clock CK indicated by SK
, The density unevenness information D0 in units of 8 bits is output from the second serial out terminal S0.

Also, FIG. 22 shows that the EEPROM 504
5 shows the timing for writing density unevenness information or density correction information. Also in this case, the information (DI) is EE-synchronized with the serial clock CK in 8-bit units.
Writing to PROM504.

By the way, in the embodiment of the present invention, the EEPROM is used in the head production process.
Information relating to density unevenness is written in the 504, and the density unevenness unique to each recording head is improved based on the density unevenness information stored in the EEPROM 504 when the recording head is incorporated into the apparatus main body.

Therefore, in order to facilitate understanding of the present invention, first, a basic factor of the occurrence of density unevenness will be described. FIG. 23 (A) is an enlarged view of information recorded on an ideal recording head. When recording is performed using this recording head, ink spots with a uniform drop diameter (droplet diameter) are printed on the paper. Line up and line up. Therefore, although FIG. 2 shows the case of so-called full ejection (all ejection ports are ON), density unevenness does not occur even in the case of halftone such as 50% output.

On the other hand, in the case of FIG. 23 (B), the drop diameters of the second and (n−2) th outlets are smaller than the average, and the (n−2) th and (n−1) th are the center diameters. Is recorded at a position shifted from the original position. That is, (n-
The number 2) is recorded to the upper right of the center, and the number (n-1) is recorded to the lower left of the center. As a result of such a recording, the area A shown in the figure appears as a thin streak, and the area B also has the (n-1) -th and (n-2) -th center distances larger than the average distance lo. As a result, a streak appears thinner than other areas. On the other hand, the C region is (n
Since the distance between the -1) th and the nth centers is smaller than the average distance lo, a streak appears as compared with other areas.

As described above, the density unevenness is mainly caused by the variation of the drop diameter and the deviation from the center position (this is generally referred to as “dirt”).
).

Next, a specific example of a method of correcting a drop diameter variation as one of the factors of the occurrence of such density unevenness will be described.

FIG. 24 shows a driving energy used for discharging ink to be applied to a heater (heating element) 507 of a discharge port,
The relationship with the drop diameter of the ink ejected at that time is shown.
As can be seen from the characteristic curve in the figure, the drop diameter tends to increase with an increase in the energy within a certain driving energy range, and thereafter almost reaches a plateau state. However, it can be seen that there is a large difference between the values of these drop diameters with respect to the driving energy in the case of the discharge port having a large diameter and the case of the discharge port having a small diameter.

Here, in order to equalize the drop diameters between the discharge ports having different diameters, referring to FIG. 7, for example, in order to control the drop diameter to the same value of lo, the driving energy of the discharge port having a small diameter is required. was a _{E 2, E 1 (E 2} > E 1) and it can be seen that it is sufficient to drive energy whereas large diameters of the discharge ports.
In this manner, the optimum drive energy is obtained in accordance with the actual drop diameter of each discharge port, and the value of the drive energy or the identification information corresponding to the value of the drive energy is shown in FIG. Non-volatile memory (EEPROM) 504
, Density unevenness caused by at least the difference in the drop diameter between the discharge ports can be removed.

In addition, when the variable control of the driving energy for each ejection port imposes a heavy burden on the main body in terms of circuit scale, for example, in the case of a recording head that performs matrix driving as shown in FIG. With each block as a minimum unit (in FIG. 2, the discharge port group connected to each of the common terminals COM1 to COMN is a minimum unit), an average value of the drop diameters of these discharge ports is obtained, and based on the average value, By writing the driving energy in the non-volatile memory 504 in the same manner as described above, density unevenness control can be performed in block units, and simplification in circuit can be realized.

Here, as the drive energy identification information described above, a control pulse width, a drive voltage, a drive current, and the like can be considered.

Next, a description will be given of a countermeasure for “distortion” which is another cause of the density unevenness.

The cause of the “skew” is that the ejection direction of the ink ejected from the ejection port is basically deflected due to the limit of the processing accuracy of the ejection port, and it is practically necessary to correct this deflection properly. Have difficulty. Therefore, as a specific method of solving the density unevenness due to this “skew”, instead of distinguishing the drop diameter and “skew” already described, the density in a certain area is detected before the product is shipped, Based on the detected value stored in the memory 504, a method of controlling the amount of ink applied to the area is adopted.

For example, as shown in FIG. 25 (A), 50% halftone recording using an ideal recording head is performed by using a recording head having "difference" or "skew" in the drop diameter as shown in FIG. 25 (B). In order to realize such that density unevenness is not conspicuous, the following is performed. That is, as shown in FIG. 7B, by bringing the total dot area in the area within the broken line a closer to the total dot area in the case of FIG. 7A, the same density can be perceived by the naked eye. In addition, the density unevenness is practically eliminated by performing the same for the region b. Such density correction control is realized in image processing of the image reading device as described below.

FIG. 25 (B) shows the processing result of the density correction control as a model for simplification of description, and α and β are dots for correction. In addition, as methods generally known as image binarization processing described below, a dither method, an error diffusion method, an average density method, and the like are known. However, with respect to these methods, the gist of the present invention (configuration requirement)
Therefore, the description is omitted.

The density correction processing according to the reference example of the present invention can be performed as, for example, a γ correction control processing in the flow of signal processing of the image reading apparatus as shown in FIG. The circuit of FIG. 26 will be briefly described.
An image signal read from a D (charge-coupled device) sensor 511 has its sensor sensitivity corrected by a shading correction circuit 512, and R (red), G of three primary colors of light are corrected by a LOG conversion circuit 513.
(Green) and B (blue) are converted into C (cyan), M (magenta), and Y (yellow) of three primary colors (print colors). Next, the C, M, Y signals are output from the Bk generation UCR circuit 514 to the C, M, Y signals.
Bk (black) generated by the three-color mixing is extracted as a common component, or a part of the common component is extracted as a black component, and input to the γ conversion circuit 515 as C, M, Y, and Bk signals. You.

The γ-conversion circuit 515 usually has several-stage functions for calculating output data with respect to input data, as shown in FIG. 27, for example, according to the density balance of each color and the user's taste of color. And the appropriate function is selected. This function curve is determined according to the characteristics of the ink and the characteristics of the recording paper.

 Next, a specific example of the γ correction processing will be described.

The γ correction circuit 516 uses the output signal from the γ conversion circuit 515 as an input signal and has a number of correction functions as shown in FIG. For example, the function shown in # 3 is a straight line having a slope of 45 ° and outputs an input signal as it is as an output signal. On the other hand, in the functions # 1 and # 2, the input signal is multiplied by a constant smaller than 1 and output. When these functions # 1 and # 2 correspond to, for example, a portion of the recording head having a high density, the input image data is corrected to a density lower than the actual density.

On the other hand, in the functions # 4 to # 6, the input image is corrected to be darker than the actual image by multiplying the input data by a coefficient larger than 1. Therefore, in this case, it is effective for a light density portion of the recording head.

In this way, in this embodiment, one function shown in FIG. 28 (actually, more types are prepared) is made to correspond to each of the ejection openings of the recording head. That is, the identification numbers of the correction functions as shown in FIG. 28 are recorded in the nonvolatile memory 504 of FIG. By referring to this identification number, the image signal is γ-corrected by the γ correction circuit 516 corresponding to each ejection port, and the correction result is sent to the binarization processing circuit 517 in FIG. The binarization circuit 517 has a function of ultimately converting the multi-valued information (indicated by 8 bits in FIG. 28) of each pixel into a binary value of 1 or 0. Binarization is performed using an error diffusion method, average density, and the like. In the embodiment of the present invention, the error diffusion method is adopted as an example, and an output result as shown in FIG. 25B can be obtained by the injector printer 518 as a binary output of the processing result.

FIG. 29 shows a detailed circuit structure example of the gamma correction circuit 516 of FIG. Where 520 is a counter, 521 is a decoder, 522-5
25 is RAM (random access memory), 526 is gamma correction ROM
(Read only memory). The color signals T1, T2 supplied from the γ conversion circuit 515 are 00, 01, 10, 11 as shown in FIG.
And the like, 00 and the like correspond in the order of C, M, Y, and Bk to perform color identification of image data. The counter 520 to which the lower bit signal T02 is input counts up at the rising edge of the signal T2 when the output of the decoder 521 is Bk (CS-Bk). In other words, the counter 520 will start counting at the beginning of the C signal. Since one set of C, M, Y, and Bk means one pixel information, the counter 520 counts up in pixel units. The output of this counter 520 is 4
RAMs 522 to 525 are connected to the address input terminals.

In these RAMs 522 to 525, the contents of the nonvolatile memory in each recording head are stored in advance in the central processing unit CP.
The data has been transferred and written via U (not shown).
The decoder 521 sequentially synchronizes the RAMs 522 to 525 in synchronization with the color signals T1, T2.
The result is that the contents of the accessed RAM are selectively output and input to the upper address of the γ correction RAM 526.

That is, the output of the counter 520 indicates the ejection port number of the recording head corresponding to the image data at that time, and RA
In the M522 to 525, the number of the gamma correction curve (eleventh # 1 to # 6) of the discharge port is recorded at the location where the discharge port number is used as an address. Therefore, the γ correction ROM 526 determines the table number by the upper address and the γ conversion circuit 515 by the lower address.
, The input image data is corrected according to one function selected from the γ correction curves in FIG. 28, and is passed to the next binarization circuit 517.

In the above-described reference example, the case where the image reading device and the ink jet recording device are connected as a copying machine and the density correction process is performed in the image reading device is shown. However, the present invention is not limited to this, and the present invention is not limited to this. In addition, the present invention can also be applied to an ink jet recording apparatus of a type that inputs R, G, B signals from the apparatus, or a facsimile apparatus, and in this case, the above-described gamma correction circuit for density unevenness correction is provided in a signal processing system in the ink jet recording apparatus. Provided.

Other Embodiment 2 FIG. 31 shows the structure of another embodiment of the present invention. In the present embodiment, for example, ground GND patterns A, B, C... Connected to the heating elements of the respective discharge ports are shown in FIG. 31 corresponding to the respective blocks of the matrix structure as shown in FIG. Prepared according to the dot diameter characteristics of each discharge port.
The GND pattern is cut using a method such as a laser cut, and the cut (indicated by a cross) is 1 and the cut is 0.
Thus, a two-stage density correction control according to the present invention is realized.

By the way, the heater board 503 shown in FIG. 18 specifically has, for example, a configuration as shown in FIG.
The printed circuit board 501 shown in FIG. 18 is provided in an ink jet recording head of an ink jet recording apparatus as shown in FIG. 33, for example.

More specifically, the heater board 503 shown in FIG.
Is formed by forming an electrothermal converter having a heating portion (ejection heater) 507 of the electrothermal converter and a wiring 531 made of Al or the like for supplying electric power to the silicon substrate by a film forming technique. Then, a top plate 533 provided with a partition wall for forming a liquid path 532 for the recording liquid is adhered to the heater board 503 to form a recording head chip.

The recording liquid (ink) is supplied to the supply port 534 provided on the top plate 533.
Is supplied to the common liquid chamber 535, and is guided into each liquid path 532 from here. When the heater 507 generates heat by energization, bubbles are generated in the ink filled in the liquid path 532, and ink droplets are ejected from the ejection port 509.

In FIG. 33, reference numeral 544 denotes a head cartridge, which integrally integrates a recording head chip using a heater board as shown in FIG. 32 and an ink tank as an ink supply source. This head cartridge 54
4 is fixed on the carriage 545 by a pressing member 541, and these can reciprocate in the longitudinal direction along the shaft 551. The ink ejected from the ejection port of the recording head reaches a recording medium 548 whose recording surface is regulated by a platen 549 disposed at a very small distance from the ejection port, and forms an image on the recording medium 548.

A discharge energy generating element disposed on the recording head chip includes a cable 546 and a terminal 505 (the 18th terminal) connected thereto.
An ejection signal corresponding to image data is supplied from an appropriate data supply source via FIG. One or more head cartridges (two in the figure), depending on the ink color used, etc.
Can be provided.

In FIG. 33, reference numeral 547 denotes a carriage motor for scanning the carriage 545 along the shaft 551;
Is a wire for transmitting the driving force of the motor 547 to the carriage 545. Reference numeral 550 denotes a feed motor coupled to the platen roller 549 to convey the recording medium 548.

FIG. 34 is a perspective view of an ink tank recording chip integrated cartridge 809 used in the ink jet recording apparatus according to the embodiment of the present invention, and FIG. 35 is a perspective view of an ink jet recording apparatus equipped with the cartridge 809. ing.

In this apparatus, the ink tank 700 has the recording head 6
The ink cartridge 809 is integrally formed with the cartridge type 008, and has a structure in which the ink impregnated and held in the ink absorber 707 in the cartridge 809 is supplied into the recording head 600.

Here, the recording head 600 includes a discharge unit 602, a supply tank unit 604, and the like. The discharge unit 602 is provided in a discharge port 602A formed on the surface facing the recording medium, a liquid path extending inward, and, for example, in each liquid path, for example, using thermal energy as discharge energy. And a common liquid chamber communicating with each liquid path.

Further, the supply tank 604 functions as a sub-tank that receives the supply of ink from the ink tank 700 side and guides the ink to a common liquid chamber in the ejection unit 602. The ink absorber 702 provided in the ink tank 700 and impregnated with ink can be formed using a porous body, a fiber, or the like. Reference numeral 704 denotes a lid member of the ink tank 700.

In FIG. 35, 809Y, 809M, 809C, and 809K (collectively referred to as "cartridge 809", and the corresponding parts in each cartridge are represented by the same numeral as "Y", "M",
Reference numerals with "C" and "K" are used), and the cartridge shown in FIG. 34 is fixed on a carriage 515.
Can be reciprocated in the longitudinal direction along. Further, the positioning with respect to the carriage 515 is performed by, for example, the recording head 600.
And a dowel provided on the carriage 515 side. Further, the electrical connection is made to the discharge section 602
A connection pad provided on a wiring board (not shown) for
The connectors on the carriage 515 may be connected.

The ink ejected from the ejection port 602A is the recording head 600
At a very short interval, the recording medium reaches the recording medium 518 whose recording surface is regulated by the platen roller 519, and an image is formed on the recording medium 518.

An ejection signal corresponding to image data is supplied to the recording head 600 from a data supply source (not shown) via a cable 516 and a terminal connected thereto, as appropriate. Cartridge 80
9 can be mounted with one or more (four in the figure) according to the ink color or the like to be used.

In FIG. 35, reference numeral 517 denotes a carriage motor for scanning the carriage 515 along the shaft 521;
Is a wire for transmitting the driving force of the motor 517 to the carriage 515. Reference numeral 520 denotes a feed motor coupled to the platen roller 519 to convey the recording medium 518.

The discharge port 602A of the cartridge 809 is made up of, for example, 128 nozzles, and is arranged in a vertical direction in FIG. 1 with a pitch of 63.5 μm. However, since it is difficult to manufacture the ejection openings 602A in exactly the same shape, characteristics such as the ejection ink amount, ejection speed, and ejection direction are slightly different for each ejection opening. Alternatively, such characteristics may change due to a change over time in use or the like. Therefore, if no correction is performed, density unevenness occurs in the recorded image as a result. This density unevenness appears in the recorded image as a streak,
The recording quality deteriorates significantly.

In this reference example, in order to eliminate these density unevenness,
As described later, correction is performed for each cartridge 809 in accordance with the characteristics.

FIG. 36 is a block diagram in the case where the configuration shown in FIG. 35 is used in a copying apparatus. The configuration and the basic operation will be described below.

For example, an image reading unit 801 including a photoelectric conversion element such as a CCD (Charg Coupled Device) reads a document image and converts it into an electric signal. At this time, three color signals of red, green and blue are output. Next, this electric signal is converted into a digital signal by an A / D converter 802, and the shading correction circuit 803
Thereby, the uneven components of the optical system and the sensor are removed.

Next, the logarithmic conversion unit 804 converts the characteristics into linearity with respect to the density, and further converts the signals related to red, green, and blue into signals related to the ink colors cyan, magenta, and yellow.

Next, the color correction circuit 805 performs an operation for removing the occurrence of dust in the color due to the characteristics of the reading unit 801 and the ink characteristics, and renders a black component. Density correction corresponding to every 600 is performed. The data corrected for each ejection port of the recording head 600 is subjected to a binarization operation by a binarization circuit 807. In this embodiment, the binarization circuit 807 performs a binarization operation using an error diffusion method.

The binarized data is sent as a drive signal to a print head 600 of an ink jet type via a print head driver 808, whereby ink is ejected. These series of controls are performed by the control unit 810 controlling the clock output from the image clock generation unit 811.

The CPU 812 includes a shading correction circuit 803, a logarithmic conversion unit 8
04, connected to the color correction circuit 805 and density unevenness correction circuit 806,
Various conditions are set. Further, the CPU 812 is connected to a ROM 813 for storing the operation program and the like and a RAM 814 for storing various set values and the like, and controls the execution of the program. Note that the RAM 814 is backed up by a battery 815 so that data is retained even when the power is turned off. Further, the CPU 812 is connected to the IC card interface 816, and is configured to be able to read data of the IC card 817 as storage means. The recording heads 600Y, 600M, 600C, and 600K are provided with ROMs 530Y, 530M, 530C, and 530K for storing their serial numbers, and are configured to be read by the CPU 812. A control unit includes the CPU 812 and the density unevenness correction circuit 806.

In the IC card 817, serial numbers of a plurality of, for example, 64 types of recording heads and characteristic information of the recording heads are input.

The characteristic information includes, for example, density correction data of each ejection port in the recording head, correction data of the temperature detecting thermistor of the recording head, and color of ink of the recording head.

FIG. 37 is a block diagram of the density unevenness correction circuit 806.
FIG. 38 is a graph for explaining data stored in the ROM 901 in the density unevenness correction circuit 806. IC card 81
The correction data for each recording head input from 7 is stored in the RAM 814, and the CPU 812 transfers the correction data to the RAM 904. That is, the selectors 902 and 903 are switched so as to select the A side, and the color information of the ink of the cartridge 809 is used as D0 and D1, and the correction data of each ejection port is used as D2 to D7.
Transfer to RAM904.

Next, the CPU 812 switches the selectors 902 and 903 to select the B side, and causes the RAM 904 to read data. The address control at this time is performed by the address control circuit 905 based on a clock signal at the time of image reading or the like. In other words, the ROM 901 is provided with image data for each pixel as A0 to A7, and correction data and the like for the ejection port on which the pixel is to be printed as A8 to A15 (however, A8, A9
Is a color control signal). Note that A8 and A9 are color information of the ink stored for performing the correction when the ejection characteristics and the like are different from the color of the ink. Is not always necessary when the configuration described above is provided for each color of ink.

Next, the storage contents of the ROM 901 will be described with reference to FIG. The ROM 901 stores a table of image data corrected in the range shown by the hatched lines in FIG. Line l1 is A1
The case where the value represented by 0 to A15 is 0, and the line l2 is A10 to A
The case where the value represented by 15 is 32 is shown, and the line 13 shows the case where the value represented by A10 to A15 is 63. For example, in the case of an ejection port having a characteristic that the amount of ejected ink is small (when values represented by A10 to A15 are small), image data having a value larger than the input image data is output. Conversely, in the case of a discharge port having a characteristic of a large ink discharge amount (when the values represented by A10 to A15 are large), image data having a value smaller than the input image data is output. In this way, it is possible to correct the density unevenness due to the difference in the characteristics of the ejection ports, and output a uniform image.

Next, the processing operation of taking in the correction data of the recording head from the IC card 817 will be described with reference to the flowchart of FIG.

After the power is turned on, the CPU 812
The serial number is read from the ROMs 530Y, 530M, 530C, 530K provided in 0 (steps 501 to 504). Next, the correction data of these serial numbers is already stored in RAM814 from IC card 817.
Is checked to see if it is on the ROM 814 (steps 505 to 508). If the correction data of the recording head 600 of all colors is in the RAM 814, the copy is permitted (step
518), and the correction data in the RAM 814 is transferred to the RAM 904 (FIG. 6 (C), step 519). When a copy key (not shown) is pressed, copying starts (step 520).
~ 521).

In addition, even if one color is used for the recording head 600 by steps 505 to 508,
If the correction data of the serial number is not developed on the RAM 814, it is determined whether the IC card 817 has correction data corresponding to the attached recording head 600 according to steps 509, 511, 513, and 515. Correction data is IC card 81
7, the necessary correction data is transferred from the IC card 817 to the RAM 814 (steps 510, 512, 514, 51).
6). Then, when the correction data of all the mounted recording heads 600 is completed, copying is permitted (step 518).
If at least one of the correction data is insufficient, copy is prohibited, and the copy operation is prohibited.

The IC card 817 can correct a plurality of recording heads, and can erase used data.

Therefore, when the correction data is transferred to the main unit, data indicating that the correction data has been used is written in the correction data, and when writing new correction data to the IC card 817, unnecessary correction data is erased and stored in that area. Can write. The correction data is written to the IC card 817 when the cartridge is purchased, or when the cartridge is purchased, a new IC card on which the correction data is recorded is obtained together. By inserting such an IC card into the main body, the correction data is read by the copier main body.

Such an IC card may be removed once the correction data has been read by the main body.

As described above, in this embodiment, the correction data of a large number of recording heads for each color can be stored by one IC card 817, which is efficient. In addition, transmission of correction data and the like can be easily performed at low cost.

Further, the storage means of the present invention is not limited to the IC card, but since the IC card can be reused, the more the card is reused, the higher the cost efficiency.

Further, since the correction data of the recording head obtained illegally can be prevented from being input to the IC card, the illegal use can be prevented.

In particular, in the case of a disposable head of a type in which ink is discarded when ink runs out, the number of times of transfer of correction data increases, and the efficiency of the IC card increases, which is more suitable for the object of the present invention. In such cases,
Although a large number of recording heads are purchased at once, it is convenient to store correction data for all the purchased recording heads in an IC card.

In the above-described reference example, as a method for removing density unevenness, a table of corrected image data is stored in the ROM 901 and correction is performed by selecting the corrected image data according to the recording head. The drive voltage for each,
The dot diameter of the ink may be made uniform by changing the drive current or the drive time. or,
The present invention is not limited to the use of thermal energy as the ejection energy of ink, but when thermal energy is used, correction may be performed by changing the temperature of the heat source of each ejection port.

As described above, according to the present embodiment, the drive mode is controlled according to each print head based on the contents of the removable storage means, so that the waste of the configuration is reduced and the image quality is deteriorated. The cost can be reduced without the need.

Next, an embodiment which is a characteristic configuration of the present invention will be described. In the following embodiment, there will be described an apparatus capable of reliably reading data from a memory integrated with a head when the head is replaced.

FIG. 40 is a view for explaining the appearance of such an embodiment. No.
In FIG. 40, reference numeral 1101 denotes a document table for placing a document or a recording material such as paper on which a test pattern is printed, reference numeral 1102 denotes a mark for positioning on the document table, and reference numeral 1103 denotes a document or record placed on the document table 1101. This shows the used recording material. Reference numeral 1104 denotes an operation unit, 1105 denotes a copy key for issuing a recording instruction, 1106 denotes a key for issuing an RHS instruction, which will be described later, and 1107 denotes a display for performing various displays, for example, displays for the RHS. A power switch 1108 turns on the power of the apparatus.
Reference numeral 1109 denotes a paper discharge port, and reference numeral 1110 denotes a door for protecting the recording head from the outside. The recording head can be replaced by opening the door.

Next, data in the EEPROM provided on the head in the present embodiment will be described.

FIG. 41 is a diagram showing allocation of data in the EEPROM provided for each head. In this embodiment, the serial number, density unevenness, correction data, drive data for setting drive conditions, and data indicating the ink color of the head are written in the EEPROM.

As shown in FIG. 41, each EEPROM in this embodiment has a capacity of at least 1024 bits, and as is apparent from the drawing, the 0th bit among the 8th bit from the 0th bit to the 7th bit. The correction data of the first nozzle of the head is allocated to the sixth to sixth bits.
The bit is SENSE, that is, bit 0 in 4 bits indicating the characteristic classification of the temperature sensor provided in the head shown in FIG.
And bit1 are assigned. The data allocation of each bit is as shown below. The addresses are given as shown.

Note that T ₁ and T ₂ are data indicating the optimum drive pulse waveform of the head, ID is data indicating the head serial number, and COLR is data indicating the color of the head.

Next, the overall block of the apparatus of this embodiment will be described with reference to FIG.

43, the description of the same elements as those shown in FIG. 36 will be omitted. In FIG. 43, a CPU 712 'has two systems of an address bus and a data bus.
The other is connected to circuits such as 04, 705, and 706, and the other is connected to a ROM in the head and a RAM for back-up. 714 '
Is a backup RA for storing data in the head
M and 703 are density unevenness measuring units.

Next, details of the main parts of the circuit shown in FIG. 43 will be described with reference to FIG.

44, blocks having the same functions as those in FIG. 29 are denoted by the same reference numerals, and description thereof will be omitted.

44, reference numeral 714 denotes the backup RAM shown in FIG. 43.
RAMs 422 to 425 are RAMs as storage means connected to the data bus, and 900 is an address from the counter 420
A selector for selecting one of the addresses from 2 ', and its switching state is controlled by the CPU 712'. 80
Reference numerals 2, 804, 806, and 808 are selectors for switching either the signal from the decoder 412 or the signal from the chip select signal generation circuit 801.

Next, the density unevenness measuring section will be described with reference to FIG.

That is, in this embodiment, the apparatus itself has a means for correcting unevenness in density caused by a temporal change of the head. That is, when unevenness occurs, firstly,
The unevenness measurement pattern shown in Fig. 20 is printed. Next, the image is read by the image reading unit 701 to perform the unevenness measurement process. The circuit shown in FIG. 45-2 is a circuit for detecting density unevenness caused by a temporal change in each head in the density unevenness measuring unit, converting correction data corresponding to the density unevenness into the RAM 714, and writing the converted data into the RAM 714.

First, a color signal whose density unevenness is currently being measured is selected from the data converted into the three primary colors by the conversion unit 704 shown in FIG. 43 and latched to the latch circuit 531. The latched image signals are added by an adder 532, and the addition result is averaged by an averaging circuit 533. The data thus averaged is stored in the temporary memory 534. Here, the data added by the adder 532 is the density of a plurality of dots recorded by each nozzle, and the sampling number can be selected from several types.

As shown in Fig. 45-1, the original is set on the original platen in such a manner that the nozzle direction B of the basic pattern (halftone 50% or the like) for density unevenness measurement is perpendicular to the arrangement direction A of the line sensors. If the resolution of the recording head 100 is the same as the resolution of the line sensor, the density data of the pixels corresponding to the number of light receiving elements of the CCD can be obtained by one CCD sampling. Obtainable. If the resolution of the CCD is higher than the resolution of the recording head, it is necessary to calculate the density of one pixel recorded from data of a plurality of light receiving elements of the CCD.

The average value density data of each nozzle is processed by the CPU 535, and a correction table shown in FIG. 28 is assigned to each nozzle. The correction table number obtained in this way is
The data is newly stored in the gamma correction RAM 714 '.

Next, the operation of the apparatus of this embodiment will be described with reference to FIG. In FIG. 46 S1, after the power is turned on by the main power supply switch 1108 shown in FIG. 40, the unevenness correction data (HS data) in the nonvolatile memory of the recording head mounted on the apparatus is transferred to the printer unit shown in FIG. Copy it to RAM 714 '(HS data) together with the ID. This process is performed whenever there is a possibility that the head has been replaced by the user, such as when the power is turned on or immediately after the head replacement door (shown in FIG. 40) is opened and closed. The RAMs 422 to 425 further store HS data obtained by the last RHS process,
Backed up by Battery 815. RAM71
4 'and RAMs 422 to 425 store respective IDs and .gamma. Correction data for each of the heads for the four colors of cyan, magenta, yellow, and black.

Thereafter, in S2, the data is transferred from the RAM 714 'to the RAMs 422 to 425. At this time, the following judgment is made in order to use the latest HS data of the mounted head. That is, as shown in FIG. 47 S8, the ID of each head copied at the time of turning on the power is compared with the head ID in the RAM 422 to 425, and if they match, the head has been subjected to the RHS process in the past and the result Is recorded on the RAMs 422 to 425, and the HS data on the RAMs 422 to 425 is used for recording (S9). Since the data in the EEPROM of the head is never rewritten, it is guaranteed that the HS data subjected to the RHS processing is always newer than the initial HS data of the recording head. Compare the ID of each head with the head ID of RAM422-425,
If they do not match, it is natural that the data in the RAM 714 'cannot be used for the current head because it belongs to another head, so the data in the RAM 714' is transferred to the RAMs 422 to 425 (S10). As shown in FIG. 47, S8, S11, S1
2. The processing of S13 is performed. In S1, only the ID data is copied without copying all the HS data, and the ID
If the data does not match the ID data in the RAMs 422 to 425, the data in the EEPROM in the head may be copied including the HS data for the first time.

After the HS data corresponding to the head is transferred to the RAMs 422 to 425, the COPY key (FIG. 40 1104) of the device operation unit (1104 in FIG. 40) is a command for performing the copying operation in FIG.
1105), etc., the input determination processing of the door switch provided on the KEY and head replacement door is performed. For simplicity, the copying operation shown in FIG. 46, S4, is the same as in the previous embodiment and will not be described. FIG. S6 is a process when the head replacement door is opened, and performs a process as shown in FIG. 48 described later. When the door is opened, the above-mentioned door switch turns off.
Then, after such switch OFF is detected in S3, the process of S6 is performed. As shown in FIG. 48, all the driving motors are stopped (S61), the lamp is turned off and the power supply of the head driving source is cut off (S62), and an error is caused by the current flowing through the head portion accessible to the user, the head. This process has the purpose of ensuring the safety of the user by stopping the physical movement of the section. After this door opening process is performed,
In S3 in the figure, the process of S6 is repeated until the door switch is turned ON, that is, the door is detected, so input of other keys is prohibited, an error is displayed on the display LED of the operation unit, and the user is notified. Notify that the door is open. When the door is closed, door shutter processing of S7 is performed. The processing will be described with reference to FIG. When it is detected that the door is closed, the head temperature control is restarted (S71), and the display of the error is stopped in preparation for printing, and the display is returned to the normal display (such as the number of copies) (S7).
2). Next, the flow returns to S1 to read the head ID data again, and it is possible to determine whether or not the head has been replaced based on this.

In the apparatus of this embodiment, processing of keys other than the keys on the operation unit described above is also performed. However, since it is not directly related to the present invention, description and description are omitted in FIG. 46.

The RHS (Reader Head Shading) operation in FIG. 46 S5 is an operation for correcting density unevenness using the device reading system. As described above, this process is to update the HS data so that the density unevenness caused by the temporal change of the recording head is read by a reading system of the device and the HS unevenness is corrected from the obtained data. is there.

Next, a reference example of a specific control flow of the RHS will be described with reference to FIG. The processing is divided into printing of the uneven reading pattern, reading by the reading system of the same pattern, and HS data calculation.

When the RHS key on the device operation unit is pressed, printing of the uneven reading pattern is performed first. The head recovery operation and S15 shown in FIG. 50 S14 correspond to this. S14 performs a series of operations, such as removing the fixed ink on the recording head, removing air bubbles by sucking ink from the discharge ports, and cooling the head heater, so that the RHS operation prints the pattern for unevenness reading in the best condition. It is necessary as a preparatory operation.

In S15, a pattern for reading unevenness shown in FIG. 45 is printed out. As a print pattern, halftone of 50% density is printed in the vertical direction in the same figure for each color in 4 blocks.
It consists of 16 block patterns. The pattern is printed at a predetermined position on the recording paper. The physical position is set so as to be convenient for error detection when reading a pattern described later. Each block is made from three lines of printing. The first and third lines discharge only 16 nozzles out of 128 nozzles, and the second line discharges all 128 nozzles, giving a total printing width of 160 nozzles. Halftone print block. The reason for recording each block with a width of 160 nozzles is as follows.
As shown in FIG. 1, when a recording head composed of, for example, 128 nozzles is used, when a pattern recorded by this recording head is read by a CCD line sensor or the like, the influence of white as the background of the recording paper is obtained. Indicates that the density data An tends to drop. Therefore, if each block is recorded by only 128 nozzles, the reliability of the density data at the end of the nozzle may be lost. Therefore, in this embodiment, 16
Prints with 0 nozzles, treats density data above a certain threshold as valid data, regards the center of valid data as the center of the nozzle, and calculates data at points separated by (number of nozzles) / 2 (64 in this case) from that point. , Respectively, corresponding to one nozzle and 128 nozzles.

After the printing of the read pattern is completed, the CPU waits for the RHS key to be pressed as shown in FIG. 50, S16. The user places the output recording paper on the original table shown in FIG. 40 with the pattern facing downward, and further places four blocks of the same color in the main scanning direction of the CCD sensor. After that, press the RHS key to
Go 17

The steps from S17 to S28 are the unevenness reading and HS data calculation part. In S17, the shading process of the CCD sensor is performed, and the uneven reading pattern is read in S18. One line here is a CCD that reads 4 blocks of a certain color at a time.
It refers to one main scan of the sensor. Therefore, in one line reading in S18, the block pattern is equivalent to the 45-2nd block of 4 blocks.
It is stored in the memory 134 shown. The read data (density data) of each of the four blocks is printed at a predetermined position on the recording paper so as to fit in a predetermined area of the memory.

Next, in S19, an error is detected for the read data stored in the memory. Since the RHS of this reference example requires the user to put the print sample on the reader, the user's erroneous operation must be taken into consideration, so that it is possible to determine whether a series of operations are performed correctly It is necessary to check as tightly as possible. In addition, even if the user's operation is correct, if the reader reads inappropriate data, the processing may not be stopped to increase unevenness. Therefore, in the RHS of this reference example, the following error detection is performed based on the read data, and an appropriate process is performed for each.

The first possible error is that the user has shifted the print sample with respect to the reading area of the reader. For example, the print sample shown in FIG. 45 is originally on the reader as shown in FIG. 51 (a) and the data shown in (b) should be obtained.
If the data is shifted in the main operation direction of the reader as shown in FIG. 2 (c), the data may be insufficient for one block or may be incomplete as shown in FIGS. 52 (e) and 52 (f). If there is a shift in the sub-scanning direction of the reader as shown in (g), data of 0 is read, and as shown in (h), data of low density is read, or in the worst case, data of a different color is read. I will. Further, if the print sample is placed at an angle as shown in FIG. 51B, the data of the neighboring nozzles will enter the area corresponding to each nozzle. In any of these cases, correct correction cannot be performed, and it is necessary to detect an error and reject the read data.
FIG. 51-2 is a view of the document table 1101 shown in FIG. 40 viewed from above, and FIG. 52 is a diagram showing print samples (a), (b), (e), and (g) placed on the document table. And (b), (d), (f), and the image data obtained by reading the respective print samples.
It is a figure which shows the relationship with (h).

In order to do this, in the present embodiment, an error occurs if the print area above a certain threshold is not located at an appropriate position (address) when the reader performs one scan.
Here, the print area means a place where a value equal to or more than a predetermined absolute value continues for each color. At this time, if a blank sheet is read and data contains 0, the print area is not recognized.
Further, as another error detection method, when the width of the print area is larger than a certain threshold, this is detected as being placed diagonally and an error is detected. (FIG. 52, (c), (d)).

RHS by shifting the print sample by the above method
Erroneous data writing is prevented. Such an error detection corresponds to an erroneous placement of the print sample by the user, and corresponds to not only a case where the print sample is simply misaligned as described above, but also a reverse placement and a reverse placement. In this case, the error can be read again by placing the print sample again and pressing the RHS button again.

However, even if the user places the print sample in the correct position, if the state of the head itself is unstable, the nozzle may suddenly fail to discharge, and the print sample is regarded as abnormal at the reading stage. There is a need. Generally 53
As shown in FIG. 7C, when only one nozzle fails to discharge, the density of the area does not decrease to the same level as the blank area. In the present embodiment, a threshold for detecting discharge failure is separately provided, and when the data in the print area is lower than this, it is determined that discharge failure occurs. At this time, if four of the four print patterns in FIG. 45 have non-discharge, this is complete discharge, but if there is no non-discharge in one area, only the remaining part is used. You may decide to do the calculation or RHS
The printing may be started again as an error of the above. Also, even in the case where there is a discharge failure in all four areas, if it is possible to cover with the printing of both nozzles, the calculation processing may be performed as it is, or without performing only the color,
The SRAM may be rewritten only for other colors. Further, the above-described threshold for the print area may be provided at a slightly higher position without specially providing the non-discharge threshold, and the threshold may be detected at the same time. In any case, it is necessary for RHS to perform non-discharge detection. FIG. 53 is a diagram showing image data when a print sample is read.

In this reference example, the error
It prevents writing wrong data to the memory and always keeps the most appropriate data in RAM813.

If no error is detected in S19, the density ratio is calculated in S24. In the present embodiment, there are two main types: a density ratio calculation and a one-line correction table number calculation. In the density ratio calculation, the ratio between the print density of each nozzle and the average density is calculated. In calculating the one-line correction table number, it is determined which of the 64 types of correction tables prepared in advance should be given to each nozzle having the above density ratio (S25). ). As described above, the output signal changed for each print input signal is written in each table. That is, for nozzles with low density,
It is only necessary to select a table that always converts the output signal higher than the input signal. Conversely, for a nozzle with a higher density, select a table that always outputs the output signal lower than the input signal. You can do it.

Here, from the point where the data is actually input in the form as shown in FIG. 53 (a) from the error detection, the description will be made sequentially with reference to FIG. 54. First, the average of the rising positions X1 and X2 at both ends is obtained, and the center value of the printing area is obtained. This is determined to be the center of the nozzle row, that is, between the 64th and 65th nozzles. Therefore, the data at the position before and after every 64 pixels from the center is the density of the first nozzle and the 128th nozzle. As a result, the print density n (i) including the connection portions at both ends is obtained by each nozzle. However, it is very dangerous to directly use the density data of the area having a width of only one pixel as the density data of the nozzle. This is because, as shown in FIG. 55, it is certain that one pixel of the reading area also includes the density due to the dots hit by the nozzles on both sides. This is because it is unavoidable to be twisted. Furthermore, it is necessary to take into account the density unevenness seen by the human eye depending on the surrounding situation including the pixel of interest. Therefore, in this embodiment, before determining the density of each nozzle, the average value of three pixels including the pixel and the pixels on both sides is obtained, and this is defined as the nozzle density ave (i).

Further, an average value AVE of ave from 1 to 128 is obtained, and this is set as the average density of all nozzles. Next, the ratio to the average density is obtained for all the nozzles. Here, it should be particularly noted that the value d (i) to be obtained is the reciprocal of the value of each nozzle density with respect to the average density. That is, d (i) = AVE / ave (i). For a low-density image, a correction with a large gradient to increase the density is required, and for a high-density image, a correction with a small gradient to lower the density is required. It is more convenient to calculate the reciprocal in this way for later calculation processing. In this way, 128 density ratios d
When (i) is obtained, the calculation of the density ratio is completed, and the data is sent to the calculation of the one-line correction table.

Here, first, a multiplication D (i) = d (i) * D (i) of the density ratio d (i) obtained by reading the unevenness this time and the density ratio D (i) up to the previous time is performed. When such an arithmetic process is performed for each correction, the result is the past d (i)
Everything is included while being multiplied. The density unevenness changes gradually, and it is meaningful to add the data up to that time to the arithmetic processing in applying the correction. Next, the table is determined. When the table number is T (i), the determination formula at this time is T (i) =
(D (i) -1) * 100 + 32. As mentioned earlier, 64 correction tables are prepared and table numbers
It is slightly tilted up and down around 32. Here, the table number 32 is a slope 1 in which the input value and the output value are always equal.
It is a straight line. This is the table that should be taken by the nozzles that provide the average density of the 128 nozzles. The remaining curve above and below is 50% density equal to the printed sample.
At (80H), there is a table in 1% increments centered on the 32nd. Therefore, T obtained by the above equation
(I) means that the signal value conversion consistent with the density ratio is always performed in the input signal of 80H. In this way, T
When 128 (i) are obtained, the one-line correction table number calculation ends.

This completes the reading of unevenness for one line, that is, one color, and the calculation of HS data (T correction table number) in which unevenness has been corrected from the data. In S26 shown in FIG. 50, it is checked whether the same processing has been completed for the four lines, that is, the heads of the four colors, and when the HS data for the four colors is calculated, the RAM 814 'is updated in the next S27. The latest HS data (T correction table number) until the RHS processing is performed is stored in the RAM 814 ', and is replaced with the calculated latest HS data.

Then, in S28, the contents of RAMs 522 to 525 are updated.
Replace with HS data.

 This concludes the description of the control flow of the RHS process.

As is clear from the above, in this reference example, when the head is replaced with a new head, the EEPROM data (γ-correction data) in the head is written into the RAM 814 ′, and the subsequent aging is performed according to the above operation. Update the data in RAM814 '. Therefore, this RAM is backed up with a battery so that the updated data is stored even when the power is turned off.

As described above, according to the present embodiment, the head device can recognize the head replacement by storing the head characteristics and management information in the head and checking the management information when the power is turned on or the door of the apparatus is opened. Recording control can always be performed under environmental conditions, driving conditions, and image processing conditions that are optimal for each head.

In particular, by detecting the opening and closing of the cover provided on the main body that is opened when the head is replaced, it is possible to properly check the management information of the head and to appropriately control the timing of performing necessary processing.

Further, in the configuration described as a reference example, since the apparatus itself has a function of recognizing and correcting a temporal change of the head characteristic (in this embodiment, a change in density unevenness between nozzles), the head is replaced in the head when the head is replaced. Recording control is performed with the data stored in the provided memory, but the data stored in the memory in the main body is updated with the passage of time, and high-quality images are always guaranteed during the lifetime of the head. It becomes possible.

In the present embodiment, the production number data is used as the head ID data, but the invention is not limited to this, and any number unique to the head may be used.

[Others]

In this embodiment, an excellent effect is obtained particularly in a recording head and a recording apparatus of a valve jet method among ink jet recording methods. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

Regarding the typical configuration and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to a sheet or a liquid path holding a liquid (ink). By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, heat energy is generated in the electrothermal transducer, and the recording head is heated. This is effective because a film in the liquid (ink) corresponding to the driving signal can be formed one by one by causing film boiling on the heat acting surface. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. 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. U.S. Pat. No. 44
Those described in 63359 and 43435262 are suitable. Further, when the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As a configuration of the recording head, in addition to a combination configuration of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in each of the above-mentioned specifications, a heat acting section A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which the is bent, is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 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 is provided. The effect of the present invention is effective even if the configuration is based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration corresponding to a discharge unit. That is,
This is because recording can be performed reliably and efficiently regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as a single recording head that is integrally formed. In addition, even if the serial type is mounted on the apparatus main body as in the above example, it is possible to electrically connect with the apparatus main body and supply ink from the apparatus main body. The present invention is also effective when a cartridge type recording head provided integrally with the recording head itself is used.

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

Regarding the type or number of recording heads to be mounted, for example, in addition to one provided for single color ink, a plurality of recording heads are provided corresponding to a plurality of inks having different recording colors and densities. May be used.

In addition, the form of the ink jet recording apparatus of the present invention may be a form used for an image output terminal of an information processing device such as a computer, a copying apparatus combined with a reader or the like, or a facsimile apparatus which shakes a transmission / reception function. It may be something.

As described above, according to this embodiment, the nonvolatile memory elements are arranged in the ink jet head, and various characteristics and correction data unique to each head are recorded in the memory element. , The print quality and the image quality can be improved, and the head yield can be determined based on the corrected quality. Therefore, the improvement can be achieved, and the reduction in manufacturing cost can be achieved.

Further, if the present invention is applied to a maintenance-free product such as a disposable head, a complicated adjustment mechanism and adjustment work are not required, and the burden on the user can be reduced.

〔The invention's effect〕

According to the image recording apparatus of the present invention, the identification information unique to the head and the correction data used for correcting unevenness of the head are configured to be stored in the RAM in the apparatus, and read out from the memory of the mounted head unit. Identification information and the
Since the replacement of the head unit is determined by comparing the identification information stored in the RAM, the replacement of the head unit can be reliably and easily determined. Further, when it is determined that the head unit has been replaced, the identification information and the correction data read from the head are stored in the RAM in the apparatus, so that the unevenness after the replacement of the head unit is achieved. The correction can be performed reliably and easily.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a digital full-color copying machine to which the present invention is applied, FIG. 2 is a cross-sectional view of FIG. 1 as viewed from the side, FIG. Fig. 5 is a diagram for explaining the operation of the scanner, Fig. 5 is a diagram for explaining the scanning order of the scanner, Figs. 6 to 8 are diagrams for explaining the film projector, and Fig. 9 is a block for explaining the overall control. FIG. 10, FIG. 10 is a timing diagram illustrating image timing, FIG. 11 is a block diagram illustrating image processing, FIG. 12 is a conceptual diagram illustrating edge processing of an image, and FIG. 13 is a configuration of a head correction unit 711. FIG. 14 is a block diagram illustrating the multi-head density unevenness correction, FIG. 15 is a perspective view illustrating the appearance of an embodiment of the multi-head, FIG. 16 is a block diagram illustrating a reference example, and FIG. FIG. 17 is a diagram showing a modification of FIG. 15, FIG. 18 is a perspective view schematically showing an external appearance of a main part of an ink jet recording head of another reference example, FIG. 19 is a circuit diagram showing a main part circuit configuration on a printed circuit board of FIG. 18, and FIG. FIG. 21 is a timing chart showing the timing of the input signal of the circuit shown in FIG. 21, FIG. 21 is a timing chart showing the timing of the signal in the read mode of the EEPROM 504 in FIG. 19, and FIG. 22 is a signal in the write mode of the EEPROM 504 in FIG. FIG. 23 is an explanatory diagram showing the relationship between the ejection openings of the recording head and the recording dots. FIG. 23 (A) shows an ideal state, and FIG. 23 (B) shows the occurrence state of density unevenness. FIG. 24 is a characteristic diagram showing a relationship between driving energy for ink ejection applied to the heating element of the recording head of FIG. 19 and a drop diameter of the ejected ink, and FIG. 50% c with ideal recording head FIG. 25 (B) is an explanatory diagram showing a halftone recording result after density correction processing by an actual recording head, FIG. 26 is a block diagram showing a circuit configuration of the image reading apparatus, and FIG. FIG. 27 is a characteristic diagram showing a relationship between an input signal and an output signal of the γ conversion circuit 515 in FIG. 26, FIG. 28 is a characteristic diagram showing a relationship between an input signal and an output signal of the γ correction circuit 516 in FIG. 26, FIG. 29 is a block diagram showing a circuit configuration example of the gamma correction circuit 516 of FIG. 26, FIG. 30 is a timing chart showing signal input / output timings of the circuit of FIG. 29, and FIG. 31 is a circuit of another reference example FIG. 32 is a perspective view showing details of the heater board portion of FIG. 18, and FIG. 33 is a partially cutaway view showing the internal structure of the ink jet recording apparatus having the recording head shown in FIG. 34 is a perspective view, and FIG. 34 is a cartridge used in an ink jet recording apparatus. FIG. 35 is a perspective view of an ink jet recording apparatus equipped with a cartridge 809, FIG. 36 is a block diagram of a copying machine using the ink jet recording apparatus of FIG. 35, and FIG. 37 is a block diagram of FIG. FIG. 38 is a block diagram of the density unevenness correction circuit 806 of the copying machine; FIG. 38 is a graph for explaining data stored in the ROM 901 in the density unevenness correction circuit 806; FIG. 40 is a perspective view showing the appearance of the apparatus of the embodiment of the present invention, and FIG. 41 shows the allocation of data in the EEPROM in the head of the embodiment shown in FIG. FIG. 42 is a diagram for explaining the types of data shown in FIG. 41, FIG. 43 is a block diagram showing the internal structure of the embodiment shown in FIG. 40, and FIG. 44 is a diagram explaining the structure of the main part of FIG. Figure 45-1 shows print sample and line sensor reading FIG. 45-2 is a diagram showing the relationship with the area, FIG. 45-2 is a diagram showing the internal configuration of the density unevenness measuring unit 830 shown in FIG. 43, FIG. 46 is a flowchart showing the operation of the apparatus shown in FIG. 40, and FIG. 46 is a flowchart showing the contents of S2 in FIG. 46, FIG. 48 is a flowchart showing the contents of S6 in FIG. 46, FIG. 49 is a flowchart showing the contents of S7 in FIG. 46, and FIG. FIG. 5A is a flow chart showing the contents of S5 in FIG. 5, FIG. 51-1 is a diagram showing data obtained when a print sample is read, and FIG. 51-2 is a case where the print sample is placed on the platen shown in FIG. FIG. 52 is a diagram showing the relationship between the read state of the print sample and the obtained image data. FIG. 53 is a diagram showing data similar to FIG. 51-1, FIG. 54, and FIG. FIG. 50 is a view for explaining the operation of the flowchart shown in FIG. 50. 600 EEPROM 808 Head correction circuits 801 and 802 ROM

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H04N 1/032 B41J 3/10 114E 1/40 H04N 1/40 Z (72) Inventor Takuyuki Matsuo 3-chome Shimomaruko, Ota-ku, Tokyo 30-2 Canon Inc. (72) Inventor Miyuki Matsubara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-1-75257 (JP, A) JP JP-A-63-34160 (JP, A) JP-A-63-170039 (JP, A) JP-A-1-288467 (JP, A) JP-A-1-1411038 (JP, U)

Claims (4)

(57) [Claims] 1. An image recording apparatus, comprising: a recording head unit having a memory storing identification information unique to a recording head and correction data for correcting printing unevenness of a recording head; Comparing the identification information read from the memory of the recording head unit attached to the image recording apparatus with the identification information stored in the storage means, and when the two do not match, Discriminating means for discriminating that the recording head unit has been replaced; and when the discriminating means determines that the recording head unit has been replaced, the identification information and the correction data are stored in the memory of the attached recording head unit. Control means for reading out and storing the same in the storage means. 2. A backup RAM for storing at least the identification information of the identification information and the correction data.
The control unit reads out the identification information from a recording head unit attached at a predetermined timing, stores the identification information in the backup RAM, and the determination unit stores the identification information and the identification information stored in the backup RAM. 2. The image recording apparatus according to claim 1, wherein the exchange of the recording head unit is determined by comparing the identification information stored in the storage unit with the identification information. 3. The apparatus according to claim 2, wherein the predetermined timing is at the time of turning on the power of the image forming apparatus or after opening and closing a door for replacement of the head unit.
An image recording apparatus as described in the above. 4. An image recording apparatus according to claim 1, wherein said recording head is an ink jet head having nozzles for discharging ink.