JP3040455B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus that forms an image using a multi-head, such as an ink jet printer.

[Conventional technology]

2. Description of the Related Art Conventionally, as an example of this type of image forming apparatus, an apparatus that converts a read image into a digital signal, performs data processing, and then forms an image using a multi-recording head is known.

In such an apparatus, there was a possibility that unevenness in the density of an output image would occur due to a characteristic variation due to the manufacturing process of the multi-recording head, a characteristic variation of the material constituting the multi-recording head, or the like.

Therefore, a storage means for storing data corresponding to the output characteristics of each head of the multi-recording head array and a means for correcting the input image data based on the stored data are provided, and both of these means prevent the aforementioned density unevenness. Such an apparatus has been proposed.

[Problems to be solved by the invention]

However, in the above conventional example, the correction data of the input image data is stored in the memory (RO) in accordance with the output characteristic unique to each recording head (recording element) of the multi-recording head array.
M), if the output characteristics of the recording head have changed due to long-term use or changes in environmental conditions, the data stored in this memory (ROM) However, the output characteristics of the recording head (recording element) cannot be sufficiently corrected even if the correction is made, and as a result, there is a problem that the density unevenness occurs in the recorded image.

An object of the present invention is to solve such a problem, and even if the density unevenness of a recorded image changes due to a change in output characteristics of a plurality of image recording elements (recording elements) arranged in a recording head (multi-head), each image can be reproduced. An object of the present invention is to provide an image forming apparatus configured to easily and accurately read and correct unevenness in density caused by the density of a recording element.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a recording head in which a plurality of image recording elements are arranged in a predetermined direction, and a direction in which the recording head is arranged on a recording medium in a direction different from the arrangement direction of the plurality of image recording elements. In the image forming apparatus having a scanning unit that scans, the scanning unit is located outside the recording area of the recording medium in the scanning range of the recording head,
A test recording unit for recording a test pattern by the recording head, a reading unit for reading a test pattern recorded on the test recording unit, and a predetermined image signal supplied to the recording head to the test recording unit. Test pattern generating means for recording a test pattern with respect to the test pattern, and moving means for moving the test pattern recorded in the test recording unit relative to the reading means along the arrangement direction of the plurality of image recording elements. And correcting the pattern recorded in the test recording unit by the reading unit while moving the pattern by the moving unit based on a result of the reading by the plurality of recording units. Correction data creating means for creating each of the elements.

The image processing apparatus further includes a memory for storing density information read by the reading unit, a plurality of the recording heads corresponding to a plurality of colors, respectively, and the test pattern generating unit includes a plurality of test heads for each of the plurality of recording heads. The corresponding test pattern can be recorded at different positions along the arrangement direction of the plurality of image recording elements.

Note that the test recording unit may include a roll-shaped recording sheet for recording the test pattern, and the moving unit may be a transport unit for transporting the roll-shaped recording sheet.

(Operation)

According to the present invention having the above-described configuration, even if the output characteristics of the recording head change and the density unevenness occurs in the recorded image formed by the plurality of image recording elements arranged in the recording head, the density is not within the scanning range of the recording head. By recording a test pattern on a test recording unit provided at a position outside the recording area of the recording medium, and creating correction data for equalizing the density based on the result of reading the test pattern, Correction of density unevenness can be easily performed.

Further, in reading the test pattern, the pattern recorded in the test recording unit is read while being relatively moved along the arrangement direction of the plurality of image recording elements with respect to the reading unit, so that each image recording element is read. It is possible to accurately read the density unevenness of the recorded image caused by the density difference, and it is possible to accurately correct the density unevenness.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments described in detail below, an image forming apparatus using an inkjet recording method will be described. In such an ink jet recording system, a recording head having a multi-nozzle provided with a plurality of nozzles for ejecting ink will be described as an example of a multi-head image recording element.

Embodiment 1 FIG. 1 is a schematic view of a first embodiment of an ink jet recording apparatus according to an embodiment of the present invention, in which recording heads 1C, 1M, 1Y, and 1Bk have ink tanks (not shown). Cyan, magenta, yellow,
Black ink of each color is supplied.

The ink supplied to the print heads 1C, 1M, 1Y, and 1Bk is supplied to each print head by a print head driver (not shown) in accordance with a print signal corresponding to print information from a control circuit (not shown). Is driven, ink droplets are ejected from each recording head, and recording is performed on the recording paper 2.

The paper feed motor 8 is a drive source for intermittently feeding the recording paper 2, and drives the paper feed roller 4 and the paper feed roller 5.

The main scanning motor 6 moves the main scanning carriage 3 to a main scanning belt.
It is a driving source for scanning in the directions of arrows A and B via 10. In this embodiment, since a precise paper feed control is required, a pulse motor is used for the paper feed motor 8 and the main scanning motor 6.

When the recording paper 2 reaches the paper feed roller 5, the paper feed roller clutch 11 and the paper feed motor 8 are turned on, and the recording paper 2 is transported on the platen 7 to the paper feed roller 4.

The recording paper 2 is a paper detection sensor provided on a platen 7
12, and the sensor information is used for position control, jam control, and the like. When the recording paper 2 reaches the paper feed roller 4, the paper feed roller clutch 11 and the paper feed motor 8 are turned off, and a suction operation is performed from inside the platen 7 by a suction motor (not shown). Adhere to the top.

Prior to the image recording operation on the recording sheet 2, the scanning carriage 3 is moved to the position of the home position sensor 9, and then forward scanning is performed in the direction of arrow A, and cyan, magenta, and yellow are moved from predetermined positions. Then, black ink is ejected from the recording heads 1C, 1M, 1Y, 1Bk to perform image recording. When the image recording for a predetermined length is completed, the scanning carriage 3 is stopped, and conversely, the backward scanning is started in the direction of arrow B, and the scanning carriage 3 is returned to the position of the home position sensor 9. During the backward scanning, the paper is fed in the direction of arrow C by driving the paper feed roller 4 by the paper feed motor 8 by the paper feed motor 8 to feed the paper.

In the present embodiment, the recording head 1 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 3 stops at the home position detected by the home position sensor 9, the recovery operation of the recording head 1 is performed. This is a process for performing a stable printing operation. In order to prevent unevenness at the start of ejection caused by a change in the viscosity of ink remaining in the nozzles of the printing head 1 and the like, the paper feeding time and the internal temperature of the apparatus are reduced. Recording head 1 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.

By repeating the operation described above, image recording is performed on the entire surface of the recording paper.

Reference numeral 14 in FIG. 1 is a density unevenness detecting means provided outside the recording area on the recording paper 2 to print a test pattern by each of the multi-recording heads 1C, 1M, 1Y, and 1Bk and read the test pattern. . The density unevenness detecting means 14 includes a test pattern recording sheet 15 formed in a roll sheet shape on which a test pattern is printed by each recording head.
A test pattern recording unit comprising a motor 16 for winding the test pattern recording sheet by a control circuit (not shown); a light source 18 for illuminating the test pattern recording sheet 15; and a test pattern recording sheet by each recording head. Read sensors 17C, 17M, 17Y, and 17Bk for reading the recording density of the test pattern recorded on 15, and RAM for temporarily storing a read signal of test pattern recording by each recording head read by each read sensor. It consists of 19 test pattern reading units.

When a density unevenness correction command signal for the recording head is issued by a control circuit (not shown), the carriage 3 on which each recording head is mounted is conveyed out of the recording area on the recording paper 2 and passes through the sensor 13. In accordance with a signal from a control circuit (not shown), a test pattern is recorded from each recording head on the test pattern recording sheet 15 of the density unevenness detecting means 14 at a predetermined timing.

After the recording on the test pattern recording sheet by each recording head is completed, the carriage on which the recording head is mounted starts reverse scanning in the direction of arrow B, and returns to the position of the home position sensor 9.

Then, the test pattern recording sheet 15 on which the test pattern recording by each recording head is completed is driven by a motor 16 by a signal from a control circuit (not shown) and is conveyed in the direction of arrow D, and is recorded by each recording head. The read test pattern is read by the read sensors 17C, 17M, 17Y, 17Bk, and the read signal is sent to the RAM 19.

The test pattern recorded here may be a uniform halftone pattern, the printing ratio may be any pattern having a ratio of about 30% to 75%, and the test pattern recording sheet 15 may be a recording paper or a porous material. Is used.

FIG. 2 is a schematic diagram for explaining a reading unit according to the first embodiment of the present invention. In order to improve the reading accuracy of the density unevenness of the test pattern by the recording head recorded on the test pattern recording sheet 15, the color filters 20R, 20G, 20
B is provided to irradiate red, green, and blue light on the cyan, magenta, and yellow test patterns recorded on the test pattern recording sheet 15. By irradiating light of complementary colors to the test patterns of cyan, magenta, and yellow in this manner, the spectral sensitivity of each of the reading sensors 17C, 17M, 17Y, and 17Bk differs for each color of the test pattern. It is not necessary to use the same sensor with the same spectral sensitivity for each sensor.
The density unevenness of each color can be read.

Further, the reading aperture width of the reading sensor used here should preferably be read by averaging the density unevenness of the test pattern to some extent. According to the experiments of the present inventors, the reading opening width was preferably about 0.2 mm to 1 mm.

FIG. 3 is a block diagram showing an electrical configuration of the first embodiment of the present invention. Here, 21C, 21M, 21Y, and 21Bk are image signals of four colors of cyan, magenta, yellow, and black, respectively. Reference numerals 22C, 22M, 22Y, and 22Bk are unevenness correction tables for the respective colors. 23C, 23M, 23Y, and 23Bk are image signals after unevenness correction for each color. 101C to 101Bk are tone correction tables for each color, and 31C to 31Bk are binarization circuits. Reference numerals 1C, 1M, 1Y, and 1Bk denote inkjet heads each having 256 nozzles for each color. Reference numeral 17 denotes a reading unit having three color filters of red (R), green (G), and blue (B). 26C, 26M, 26Y, 26Bk is the reading unit 17
And read signals of R, G, B, and Bk, respectively. 19 is RAM for temporarily storing R, G, B, Bk signals, 105 is R,
This is a CPU that calculates unevenness correction data based on the G, B, and Bk signals. 28C, 28M, 28Y, 28Bk are cyan, magenta,
This is unevenness correction data for yellow and black. 29C, 29
M, 29Y, and 29Bk are unevenness correction RAMs for each color. 30C, 30M, 30
Y and 30Bk are unevenness correction signals for each color.

The image signals 21C to 21Bk are converted by the unevenness correction tables 22C to 22Bk so as to correct the unevenness of the heads 1C to 1Bk. As shown in FIG. 4, the unevenness correction table has Y = 0.
Correction straight line with a slope of 0.01 from 70X to Y = 1.30X
It has 61 lines and switches the correction straight line according to the unevenness correction signals 30C-30Bk. For example, when a signal of a pixel to be printed by a nozzle having a large dot diameter is input, a correction straight line having a small inclination is selected, and when a nozzle having a small dot diameter is selected, an image signal is corrected by selecting a correction straight line having a large inclination. .

The unevenness correction RAM stores a correction straight line selection signal required for correcting unevenness of each head. That is, an unevenness correction signal having 61 types of values from 0 to 60 is stored for 256 nozzles, and the unevenness correction signals 30C to 30Bk are output in synchronization with an input image signal.

The signals 23C to 23Bk whose unevenness has been corrected by the γ straight line selected by the unevenness correction signal are the tone correction tables 101C to 101C.
01Bk, where the gradation characteristics of each head are corrected and output. The signals are then converted to binary circuits 31C, 31M, 31Y,
It is binarized by 31Bk and drives heads 1C, 1M, 1Y, 1Bk,
A color image is formed.

Embodiment 2 FIGS. 5 (A) and 5 (B) are schematic diagrams of a second embodiment of the image forming apparatus according to the present invention. This drawing shows a part of an image forming apparatus using a full multi-recording head in which the recording width of the recording heads 1C, 1M, 1Y, and 1Bk is A4 width (up to 297 mm).

In this embodiment, when normal image recording is performed on the recording paper 2 by the recording heads 1C, 1M, 1Y, and 1Bk as shown in FIG. 2, the pickup roller 39 is conveyed onto the paper conveyance belt 40 by rotating the pickup roller 39 in the direction of arrow F by a control circuit (not shown), and then the rotation roller 41 is rotated by the same control circuit. Thereafter, the recording paper 2 is transported in the direction of arrow E together with the paper transport belt 40, image recording is performed by the recording heads 1C, 1M, 1Y, and 1Bk, and the paper is discharged.

When a density unevenness correction command signal for the recording head is issued by a control circuit (not shown), the carriage 3 mounted with each recording head and supported on the rail 37 is moved in the direction of arrow G by the motor 6 and the belt 10 '. And is transported out of the image recording area on the paper transport belt 40. afterwards,
The density unevenness detecting means 14 is moved by a transport means (not shown) to the carriage 3 on which the recording head is mounted and the paper transport belt.
The test pattern recording sheet 15 formed in a roll shape of the test pattern recording section of the density unevenness detecting means 14 is transported between the carriages 40 and immediately below the carriage 3 on which the recording head is mounted.
Is reached, the recording head is driven by a control circuit (not shown), a test pattern is printed on the test pattern recording sheet 15, the recording sheet 15 is transported in the direction of arrow H, and the test pattern reading unit is moved. The test pattern recorded by each recording head is read by the read sensor 17.

Here, when recording a test pattern on the test pattern recording sheet 15 by each recording head, if recording is performed while moving both the test pattern recording unit and the recording sheet, the recording position of the test pattern to be recorded is Since the accuracy is reduced, the recording sheet 14 is moved in the direction indicated by the arrow H while the test pattern recording unit on which the recording sheet 15 is mounted is stopped immediately below the single recording head. The test pattern is recorded by the recording head 1C while being conveyed at the same speed as the recording speed of the test pattern. After that, the test pattern recording section is moved again in the direction of the arrow I (for example, by a distance 1 between recording heads), and then the test pattern recording section is again recorded. And then perform test pattern recording by controlling the recording head 1M to form a test pattern. .

Third Embodiment FIG. 6 is a schematic diagram showing a third embodiment of the image forming apparatus according to the present invention. In this embodiment, a test pattern is printed by the multi-recording heads 1C, 1M, 1Y, and 1Bk, and the density unevenness correction unit for reading the test pattern is printed.
A line-shaped read sensor 32 and a light source 33 are used for 14 (provided outside the recording area on the recording paper 2).

That is, by configuring the reading sensor 32 for reading the test pattern by each recording head printed on the test pattern recording sheet 15 configured in a roll sheet shape as in the present embodiment by a linear shape, It is easy to keep the distance between the test pattern recording sheet 15 and the reading sensor 32 constant, and since only one reading sensor is required, the device configuration can be reduced.

As shown in FIG. 7, on the reading surface side of the reading line sensor 32, color filters of red, green, and blue are arranged in accordance with the positions of the test patterns printed by the recording heads on the recording sheet 15. 34R, 34G, and 34B are provided to improve the reading accuracy of the reading sensor 32 for each color of the print pattern. Then, the read signals of the respective colors from the read sensor 32 are sent to the amplifiers 35C, 35M, 35Y, and 35Bk, then converted into digital data by the A / D conversion circuit 36, and stored in the RAM 19 all together.

That is, as shown in FIG. 8A, the read data of the print pattern of each recording head printed on the recording sheet 15 and read by the read line sensor 32 through the color filters 34R, 34G, and 34B. Since the amount of reflected light of each color from the recording sheet is different, the output value of each color is different. For example, when the A / D conversion circuit is configured with 8 bits, the output value of each color is converted into 8 bits of the dynamic range. Since the data must be converted into digital data within the width, the resolution of the read data of each color is reduced.

Therefore, as shown in FIG. 8 (B), the read signal of each color is amplified by the amplifiers 35C, 35M, 35Y and 35Bk, and the sensor output values of the read signals of each color are adjusted so as to be substantially the same. Since the read signal width at the time of A / D conversion can be set narrower, the resolution of data in 8 bits can be increased, and the read accuracy can be further improved. .

Embodiment 4 FIG. 9 shows a fourth embodiment of the ink jet recording apparatus according to the present invention. In this embodiment, the carriage 3 on which the recording heads 1C, 1M, 1Y, and 1Bk are mounted is scanned in the AB direction, and the carriage 3 is scanned once when the test pattern print is recorded on the test pattern recording sheet 15. The test pattern is printed by the recording head of one color each time, and the reading line sensor 32 reads one test pattern recorded on the test pattern recording sheet 15 when the reading line sensor 32 reads the test pattern.
After reading the color pattern print, the carriage 3 is scanned again, and the test pattern is printed on the test pattern recording sheet 15 by the next print head.

That is, by reading the test pattern print recorded on the test pattern recording sheet of each recording head for each color as in this embodiment, the capacity of the RAM 19 for storing test pattern read data is reduced by one. / 4, and the device configuration can be reduced.

(Others) The present invention brings about an excellent effect particularly in a bubble jet type recording head and a recording apparatus proposed by Canon Inc. 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.

As for the representative 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). Applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, thereby causing the electrothermal transducer to generate thermal energy, thereby causing the recording head to emit heat energy. 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. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. 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 JP-A-63359 and JP-A-4345262 are suitable. Further, when the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As a configuration of the recording head, in addition to a combination configuration (a linear liquid flow path or a right-angled liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in the above-mentioned specifications, A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which is disposed in a bending region, 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 opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed 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 one integrally formed recording head.

In addition, even with the serial type printer as in the above example, the recording head fixed to the main unit or attached to the main unit enables electrical connection with the main unit and supply of ink from the main unit. The present invention is also effective when a replaceable chip type print head or a cartridge type print head having an ink tank provided integrally with the print head itself is used.

Further, it is preferable to add recovery means for the print head, preliminary auxiliary means, and the like provided as a configuration of the printing apparatus in the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer 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 print heads to be mounted, for example, in addition to one provided for single color ink, a plurality of print heads are provided corresponding to a plurality of inks having different print colors and densities. May be used. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also extremely effective for an apparatus provided with at least one of full colors by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink that solidifies at or below room temperature and softens or liquefies at room temperature, or the ink itself in an inkjet method. In general, the temperature is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. I just need. In addition, the temperature rise due to thermal energy can be positively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or ink that solidifies in a standing state to prevent evaporation of the ink can be used. In any case, the ink is liquefied by the application of the thermal energy according to the recording signal, and the ink is liquefied, and the liquid ink is discharged. The present invention is also applicable to a case where an ink that liquefies for the first time by energy is used. The ink in such a case is disclosed in
No. -56847 or JP-A-60-71260, while being held as a liquid or solid substance in a porous sheet recess or through hole, facing the electrothermal converter. It is good also as a form. In the present invention,
The most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

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

〔The invention's effect〕

As described above, according to the present invention, in an image forming apparatus that performs image recording with a recording head (multi-head) in which a plurality of image recording elements are arranged along a predetermined direction,
It is possible to easily and accurately read and correct the density unevenness caused by the density difference between the image recording elements, and always record a high-quality image.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention, FIG. 2 is an explanatory diagram of a reading section in the first embodiment, and FIG. 3 is a block diagram showing an electrical configuration in the first embodiment. Fig. 4 is a diagram showing a density unevenness correction straight line, Figs. 5 (A) and 5 (B) are schematic diagrams showing a second embodiment of the present invention, and Fig. 6 is a third diagram of the present invention. FIG. 7 is an explanatory view of a reading section in the third embodiment, FIGS. 8 (A) and 8 (B) are explanatory views of the third embodiment, FIG. FIG. 9 is a schematic diagram showing a fourth embodiment of the present invention. 1C, 1M, 1Y, 1Bk Recording head, 2 Recording paper, 3 Carriage, 4 Paper feed roller, 5 Paper feed roller, 6 Main scanning motor, 7 Platen, 8 ... paper feed motor, 9 ... home position sensor, 10 ... main scanning belt, 10 '... belt, 11 ... clutch, 12 ... paper detection sensor, 13 ... sensor, 14 ... density unevenness detection means , 15 ... Recording sheet, 16 ... Motor, 17C, 17M, 17Y, 17Bk ... Reading sensor, 18 ... Light source, 19 ... RAM, 20R, 20G, 20B ... Filter, 21C, 21M, 21Y, 21Bk ... Image signal, 22C, 22M, 22Y, 22Bk ... Correction table, 23C, 23M, 23Y, 23Bk ... Image signal, 26C, 26M, 26Y, 26Bk ... Read signal, 28C, 28M, 28Y, 28Bk ... ... Correction data, 29C, 29M, 29Y, 29Bk ... Correction RAM, 30C, 30M, 30Y, 30Bk ... Correction signal, 31C, 31M, 31Y, 31Bk ... Binarization circuit, 32 ... Read sensor, 33 ... … Light source, 34R, 34G, 34B …… fill , 35C, 35M, 35Y, 35Bk ... amplifier, 36 ... A / D conversion circuit, 101C, 101M, 101Y, 101Bk ... gradation correction table, 37 ... rail, 38 ... cassette, 39 ... pickup roller , 40 ... paper transport belt, 41 ... roller.

Continuation of front page (56) References JP-A-4-169239 (JP, A) JP-A-2-172755 (JP, A) JP-A-64-63171 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) B41J 2/01 B41J 29/46

Claims (3)

(57) [Claims] A recording head having a plurality of image recording elements arranged in a predetermined direction; and scanning means for scanning the recording head with respect to a recording medium in a direction different from the arrangement direction of the plurality of image recording elements. In the image forming apparatus, a test recording unit for recording a test pattern by the recording head in a scanning range of the recording head by the scanning unit and outside a recording area of the recording medium, and recording in the test recording unit Reading means for reading the test pattern obtained, test pattern generating means for supplying a predetermined image signal to the recording head to record a test pattern on the test recording section, and recording the test pattern on the test recording section. Moving means for moving a test pattern relative to the reading means along an arrangement direction of the plurality of image recording elements; And correcting the pattern recorded on the test recording unit by the reading unit while moving the pattern by the moving unit based on a result of the reading by the plurality of recording units. An image forming apparatus comprising: a correction data creation unit that creates a correction data corresponding to each element. 2. The apparatus according to claim 1, further comprising a memory for storing density information read by said reading means, a plurality of said recording heads corresponding to a plurality of colors, respectively, and said test pattern generating means comprising: 2. The image forming apparatus according to claim 1, wherein a test pattern corresponding to each head is recorded at a different position along an arrangement direction of the plurality of image recording elements. 3. The test recording section has a roll-shaped recording sheet for recording the test pattern, and the moving means is a conveying means for conveying the roll-shaped recording sheet. The image forming apparatus according to claim 1.