JP2003211770A - Color image recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color image recorder capable of forming a high quality color image by eliminating color shift due to eccentricity of a recording paper conveyance roller and color variation due to density variation of image dots. <P>SOLUTION: This color image recorder comprises a recording means that records an image in a color order of k, c, m, and k and records a resist mark on a recording paper for a predetermined interval at the same time when an image of the color of k is recorded, a reading means for reading the resist mark, a calculation means for calculating variation in a moving speed of the recording paper based on the read information of the resist mark, a data producing means for producing correction data for an image recording timing in a line unit by the recording means of colors of c, m, and y based on the calculated variation in the moving speed, and a control means for controlling the image recording timing by the recording means of colors of c, m, and y based on the correction data produced by the data producing means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image recording apparatus for printing color image data without color misregistration.

[0002]

2. Description of the Related Art A schematic structure of a conventional color image recording apparatus is shown in FIG.

In the figure, reference numeral 1001 is a roll-shaped recording paper, and 1001 'is a long continuous recording paper fed from the recording paper roll 1001 at the time of printing. Further, 1002 is a guide roller,
Reference numeral 3 is a recording head. An image is formed on the surface of the recording paper 1001 ′ fed from the recording paper roll 1001 while passing through the recording head 1003.

Reference numeral 1003 denotes a four-color recording head of, for example, Y (yellow), M (magenta), C (cyan), and K (black), and the recording heads 1003 are independent for each color. Then, on the surface of the recording paper 1001 ′, an image is formed for each color when passing the position of the recording head of each color.

Further, 1004 is a recording paper transport roller for transporting the recording paper, and 1005 is a pinch roller, which is in contact with the recording paper transport roller 1004 and sandwiches the recording paper between the recording paper transport roller 1004 and the recording paper transport roller 1004. Is for transmitting the rotation of the recording paper to the recording paper to convey the recording paper.
A roller 1006 winds up the recording paper on which the image has been recorded.

The conventional apparatus has such a configuration as described above. The recording paper 1001 'is moved between the recording heads 1003 to form an image for each color and print a color image.

However, the recording paper roll 1001, the guide roller 1002, the recording paper conveying roller 1004,
Due to the eccentricity of the rotation system such as the pinch roller 1005,
The conveyance speed of the recording paper is not constant, the image position on the recording head is slightly deviated for each color, the recording dots of the respective colors are deviated from each other, and color unevenness occurs.

In particular, the rotating system that exerts a great influence is often the recording paper carrying roller 1004 for carrying paper.

For example, as shown in FIG. 4, the recording paper transport roller 1004 having a radius r1 has an original center axis O.
Consider a case where the rotation axis X is located at a position eccentric by ΔL. In this case, the maximum radial length r2 viewed from the rotation axis X is longer than the original radius r1 of the recording paper conveyance roller 1004 by ΔL, and the minimum radial length r3 viewed from the rotation axis X is Recording paper transport roller 100
When the recording paper conveyance roller 1004 is driven to rotate at a constant speed by ΔL smaller than the original radius r1 of 4, the peripheral speed at the position of the minimum radial length r3 becomes slower, and conversely the maximum radial direction. The peripheral speed at the position of the length r2 becomes fast, and the feeding speed of the recording paper has a fast portion and a slow portion. However, conventionally, the image formation has been performed by aligning only the image recording start position on the recording paper for each color on the assumption that the conveying speed of the recording paper is constant.

[0010]

As a result, the image of the first color is recorded, for example, as shown in FIG. In the image of (a) of 5, h is a dot of the image,
The horizontal direction of the drawing is the main scanning direction (recording paper feed direction (Y direction)), and the vertical direction is the sub-scanning direction (nozzle array direction of the recording head and transverse direction of recording paper (X direction)).

In this figure, the nip point of the pinch roller 1005 with respect to the recording sheet conveying roller 1004 at the start of printing is almost the same as the point A2 of the recording sheet conveying roller 1004 (see FIG. 4B). When the position is close to the radius r1 and the original transport speed can be secured, it is ideal that the dot h of the maximum size, like the position of the region h1, is in contact with the adjacent dot at the contour position. In this state (dot interval Δh1), the nip point with respect to the recording paper conveyance roller 1004 exhibits the maximum radius r2, like the A1 point of the recording paper conveyance roller 1004 (see FIG. 4B). When the position is close to the position and the transfer speed is higher than the original transfer speed, the dots h of the maximum size are adjacent to each other like the position of the area h2. Becomes larger away from the state and the door (dot interval Δh2).

Then, the nip point with respect to the recording sheet conveying roller 1004 is a position close to a position having the minimum radius r3 like the point A3 of the recording sheet conveying roller 1004 (see FIG. 4B), and originally, When the transport speed is slower than the transport speed of, the maximum size dot h partially overlaps with the adjacent dot like the position of the region h3 (dot interval Δh3). .

In this state, the image of the first color is formed, and then the image formation of the second color is started.
As for the color, the influence of the eccentricity of the recording paper conveyance roller 1004 is shown in FIG.
As shown in (b) of No. 3, the dot shift appears with respect to the dots of the first color.

Here, up to the recording head for the second color after the image formation for the first color, the head mounting space, other space for maintenance and supply, and in some cases, a space for drying the ink, Since a mounting space such as an auxiliary device for drying is required, a certain interval or more is required.

For example, even if the recording paper is conveyed at a speed of about 33 inches per second, if the time interval between the first color and the second color is secured for 1 second in consideration of the ink drying time, the first The distance between the second color and the second color is 33 inches, about 840
mm is required.

However, before the image recording of the second color,
When a slip occurs between the recording paper conveyance roller 1004 and the recording paper, the recording paper moves due to the eccentricity of the recording paper conveyance roller 1004 between the first color image formation and the second color image formation. The influence of the speed change on the recorded image extends to different positions in the recorded image.
The second color image will not match.

Further, due to backlash of the driving force transmission system of the recording paper transport roller 1004, the actual transport start will be delayed a little. Therefore, it is conceivable that the state of speed change due to the influence of the eccentricity of the recording paper conveyance roller 1004 may be slightly different.

Therefore, as shown in FIG. 5B, the positions of the first-color dots and the second-color dots are displaced. Due to the deviation of the dot positions, the color of the non-overlapping area is different from that of the overlapping area, and this is a slight deviation but deteriorates the image quality. In addition, the occurrence of a dense portion of dots and a rough portion due to the effect of the eccentricity of the recording paper conveyance roller 1004 means that the distribution of density is different, and therefore when the same color is used for color filling, This causes unevenness, which also deteriorates the image quality.

Therefore, an object of the present invention is to provide a color image recording apparatus capable of forming a high-quality color image by eliminating color misregistration due to eccentricity of a recording paper conveying roller and color unevenness due to density of image dots. Especially.

[0020]

In order to achieve the above object, the present invention has the following constitution. That is, in a recording paper conveying roller that conveys a recording paper, and a color image recording apparatus that performs line-by-line printing recording of different colors in the same area on the recording paper when the recording paper is conveyed by the recording paper conveying roller, The color order of the recording means is k, c, m, y
The recording mark is recorded on the recording paper at the same time as the recording of the k color at a constant time interval, the reading means for reading the registration mark, and the calculating means for calculating the moving speed displacement of the recording paper from the read information of the registration mark. And a data creating means for creating correction data of print recording timing in line units by the recording means of the colors c, m, and y based on the calculated moving speed displacement of the recording paper, and the data creating means. C based on the corrected data
and a control means for controlling the print recording timing of the recording means for the m and y colors.

The print recording means is a drop-on-demand ink jet head arranged in a plane.

Further, a recording paper conveying roller for conveying the recording paper and a color image recording for performing line-by-line printing recording with different colors in the same area on the recording paper when the recording paper is conveyed by the recording paper conveying roller. In the apparatus, the color order of the recording means is k, c, m, and y, the recording mark is recorded on the recording paper at the same time as the registration mark is recorded at a constant time interval, and the reading means reads the registration mark, Calculation means for calculating the moving speed displacement of the recording paper from the read information of the registration mark, and based on the calculated moving speed displacement of the recording paper, the print recording timing of the line-by-line by the recording means of the colors c, m and y. Data creating means for creating correction data, and print recording timing by the recording means of c, m, and y colors based on the correction data created by the data creating means. In a color image recording apparatus for producing a predetermined output product by a post-processing device or the like using continuous paper as a recording paper for high-speed processing, the registration mark is prohibited from being printed. It is characterized by recording in the area.

Further, a recording sheet conveying roller for conveying the recording sheet and a color image recording for performing line-by-line printing recording in different colors on the same area on the recording sheet when the recording sheet is conveyed by the recording sheet conveying roller. In the apparatus, the color order of the recording means is k, c, m, and y, the recording mark is recorded on the recording paper at the same time as the registration mark is recorded at a constant time interval, and the reading means reads the registration mark, Calculation means for calculating the moving speed displacement of the recording paper from the read information of the registration mark, and based on the calculated moving speed displacement of the recording paper, the print recording timing of the line-by-line by the recording means of the colors c, m and y. Data creating means for creating correction data, and print recording timing by the recording means of c, m, and y colors based on the correction data created by the data creating means. In a color image recording device for producing a predetermined output product by a post-processing device or the like using continuous paper for recording paper for high-speed processing, the registration mark is recorded on the recording paper. It is characterized in that it is recorded in the printing prohibited area between the respective output objects in the carrying direction.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram showing an example of the present invention, and FIG. 2 is a control block diagram.

In FIG. 1, 1 is a recording paper roll,
Recording paper (recording sheet) 1'which is a recording medium on the outer periphery of the paper core
It has been rolled. In this example, the case of an inkjet color recording apparatus will be described below. Here, the material of the recording paper may be pulp paper, a plastic film sheet, or the like, and further may be chemically synthesized paper or paper obtained by combining these materials. It is preferable that recording is possible and that there is no expansion or contraction. There are various recording methods such as electrophotographic method and thermal transfer method.
The present invention can be applied to recording methods other than the inkjet method.

In this color recording apparatus, a guide roller 2 is arranged near the setting position of the recording paper 1 '.
Further, a recording paper conveying roller (driving roller) 5 is arranged downstream of the roller 2. Further, a take-up roller 7 is arranged on the downstream side of the recording paper conveyance roller 5, and the end portion of the recording paper 1 ′ is guided to the recording paper conveyance roller 5 via the roller 3.

A recording system is installed between the roller 2 and the recording paper conveying roller 5, and a recording paper winding system or a cutting system (not shown) is arranged on the downstream side of the recording paper conveying roller 5. Reference numeral 3 denotes an inkjet head that constitutes a recording system, and in the present example, a head having a line configuration that covers the recording area, and forms an image on the moving recording paper 1 '.

The ink jet head 3 is supplied with inks of a plurality of different colors. In this embodiment, Y, M, and
Four colors of C and K are used, and a predetermined color image is formed by superposing each color.

Reference numeral 4 denotes an optical mark reading head. The mark reading head 4 reads a registration mark for recording position control, which will be described later, recorded on the recording paper 1'and also reads an edge of the recording paper 1 '. For example, CCD
A (charge coupled device) linear image sensor (solid-state line image sensor) is used. This image sensor has a one-dimensional position resolution, and therefore it is possible to identify which mark on the recording sheet and what width is detected from the output signal of the image sensor.

Based on the output of the mark reading head 4, the control unit 101 obtains these registration marks for controlling the recording position together with the information on the edge of the paper, and controls the paper feed and the recording start timing.

A pressing roller 6 is arranged in pressure contact with the peripheral surface of the recording paper carrying roller 5, and the recording paper carrying roller 5 cooperates with the pressing roller 6 to hold the recording paper 1 '. The recording paper 1'can be fed by rotating the recording paper conveying roller 5.

In this example, the image quality is controlled by controlling the recording timing in the main scanning direction (recording paper conveying direction) so that the dots (line images) are arranged at equal intervals in the main scanning direction. The present invention will be described in detail below.

FIG. 2 shows a control block diagram of the present invention.
In the figure, 5 is a recording paper carrying roller, 102 is a drive motor for driving the recording paper carrying roller 5, and 201 is a rotation detector configured to directly connect or transmit rotation to the rotary shaft of the recording paper carrying roller 5. The rotation detector 201 detects a constant angle position for one rotation.

The rotation detector 201 is constructed, for example, as follows. That is, a disc that interlocks with the rotation of the recording paper conveyance roller 5 is provided, and a position marker hole is provided in a part of this disc, and the light source and the light receiving element are arranged so as to face each other through the disc. The photo coupler described above is provided at a fixed position, and the position of the position marker hole is detected by transmission of light by the photo coupler. Of course, the present invention is not limited to this, and if the configuration is such that it can be detected when the specific angle position in one rotation of the recording paper transport roller 5 is reached, a configuration is provided in which a magnet is provided on the disk and the rotation is detected by a magnetic sensor. It is also possible to use various currently known position detecting means, such as a configuration in which a protrusion is provided on a disk and a micro switch provided at a fixed position is operated to detect arrival at the specific angular position.

Reference numeral 103 is a drive circuit for controlling the drive motor 102, 202 is a timing correction unit for controlling the dot recording timing of the ink jet head 3, and 20 is a timing correction unit.
Reference numeral 3 denotes an address control unit for extracting the correction amount data from the correction data unit 204, the timing correction amount data corresponding to the rotation of the recording paper conveyance roller 5.

The correction data section 204 has a function that the recording paper conveyance speed changes due to the eccentricity of the recording paper conveyance roller 5.
6 is a timing correction data table that changes the dot recording timing of the inkjet head 3 so that the dot recording positions in the main scanning direction are arranged in a uniform manner on the recording paper 1 '. Reference numeral 104 is a head controller, and 3 is an inkjet head. Reference numeral 101 is a control unit that controls necessary control of the entire system.

Reference numeral 205 is a marker position detector for optically reading a marker recorded on the recording paper 1'with a registration mark of one line for n dots.

The output signal of the marker position detector 205 is transferred to the line position calculation unit 206. The line position calculation unit 206 is a calculation unit that calculates the line position of the registration mark, which is a position marker on the recording paper, based on the signal. Reference numeral 207 denotes a positional deviation amount calculation unit that, based on the line position information from the line position calculation unit 206, a marker position (registration mark position) and a respective marker position (registration mark position) with respect to the rotation angle of the recording paper at the virtual constant speed conveyance. This is a position shift amount calculation unit that calculates a shift amount from the registration mark position).

Reference numeral 208 denotes a correction data table creating section for calculating the correction amount of the dot recording timing of the recording head with respect to the rotational angle position of the recording paper conveying roller from the displacement amount. The data created by the correction data table creation unit 208 is transferred to the correction data unit 204 of the color image recording apparatus.

In this example, the ink jet head 3 is driven while the recording paper conveying roller 5 is driven to rotate and the recording paper is conveyed.
The sample print with the registration marks formed at equal time intervals by
The measurement is performed, the speed fluctuation due to the eccentricity of the recording paper conveyance roller 5 is measured, and a conversion table for adjusting the image forming timing in dot units corresponding to the speed fluctuation is obtained, which is used as a correction data section of the color image forming apparatus. Set it to 204.
Then, in the color image recording apparatus, at the time of image recording, the image forming timing of each line with respect to the main scanning direction is adjusted according to the table of the correction data unit 204, and the timing correction unit 2 is arranged so that adjacent dot intervals have a constant pitch.
In this method, the image forming timing of the inkjet head 3 is controlled by performing correction with 02.

Next, the operation will be described.

The correction data creation will be described first. In this example, the registration mark is recorded on the recording paper at the same time as the image by the inkjet head 3k. The registration mark is
For example, one line of n dots is printed on one end of the recording paper at a rate of one line. At that time, the recording paper is carried by the recording paper carrying roller 5, and the recording paper carrying roller 5 is driven by the drive motor 102. The drive motor 102 starts operating when a command signal is transferred from the control unit 101 to the drive circuit 103, and is recorded at a constant speed under the control of the drive circuit 103.

The recording start timing in this case is the rotation detector 20 which rotates in accordance with the rotation of the recording paper conveying roller 5.
When the marker hole of the disk 1 passes through the photocoupler position, the detected pulse is transferred to the timing correction unit 202, and the timing correction unit 202 transfers the recording timing to the head control unit 104 in the "no recording timing correction" mode. Start outputting the control signal of.

That is, the control unit 101 generates the dot recording timing signal ts at a constant time interval in order to obtain the dot interval for obtaining the dot density corresponding to the resolution during image formation (printing), and the timing correction unit 202. Then, the dot recording timing signal t is supplied to the head controller 104 after the necessary correction is applied to the head controller 104.
The inkjet head 3 is drive-controlled to form dots in the main scanning direction (recording paper conveyance direction) of the image at the timing of s, but in the mode of "no recording timing correction", the recording timing signal ts is corrected. The timing correction unit 202 gives it to the head control unit 104 without adding it at all.

When the head control unit 104 receives the uncorrected recording timing signal given from the timing correction unit 202 and the image data signal of the registration mark from the control unit 101, the head control unit 104 causes the timing of this recording timing signal. Then, the inkjet head 3 is controlled so that the inkjet head 3 forms dots corresponding to the image data of the registration mark.

As a result, an image corresponding to the image data is formed on the recording paper by the ink jet head 3, and the registration mark is printed.

The registration mark thus obtained on the recording paper is formed ignoring the transport speed. On the other hand, the recording paper conveying roller 5 has a slight eccentricity. Therefore, the recording paper conveyance speed is not constant and changes with periodicity. Therefore, the registration mark spacing is not uniform. The registration mark on the recording paper has a positional deviation characteristic peculiar to this recording apparatus.

Further, since the recording start position of the registration mark on the recording paper and the rotation angle position of the recording paper conveyance roller at the time of recording start can be known, there is information corresponding to the registration mark and the rotation angle position of the recording paper conveyance roller.

Therefore, next, a process for obtaining data for correcting this is performed. The marker position detector 206 reads the marker portion (registration mark portion) on the recording paper at a constant speed to measure the pitch of the registration mark.

When the detection signal thus obtained is given to the line position calculation unit 207, the line position calculation unit 207 calculates the mark start line position coordinates for each marker number based on this. As a result, the characteristics shown in FIG. 6A are obtained.

As can be seen from this figure, if the recording paper is fed at a constant speed, it is possible to obtain the straight line characteristic shown as the constant line A in FIG. Since the conveyance speed of the recording paper is not constant due to the eccentricity of the recording paper conveyance roller 5 or the like, a curve B is drawn.
If the recording paper conveyance speed is constant, the distance between marks will be a constant value, but since it varies due to eccentricity, the variation amount is obtained and the dot recording timing is corrected. That is, since the transport speed changes with a periodic wave that changes abruptly with one rotation as one cycle, such a curve is drawn.

The difference between the constant line A and the characteristic B is the positional deviation at each mark position.

The data of the characteristic curve obtained by the line position calculation unit 207 is transferred to the next position shift amount calculation unit 208. Next, the position shift amount calculation unit 208 calculates the position shift amount for each mark location. Since the recording paper conveyance roller 5 is rotating at a constant speed and the mark position and the rotation angle position linearly correspond to each other, the positional deviation amount with respect to the rotation angle of the recording paper conveyance roller 5 is calculated based on this. The calculation here is a so-called trend removal process in which the linear slope is subtracted from the curve characteristics, and the difference between the dot recording position when it is assumed that the recording paper is fed at a constant speed and the actually recorded dot position is calculated. You are asking for it.

By this calculation, the positional deviation amount Δh-rotation angle characteristic as shown in FIG. 6B can be obtained. This characteristic information is transferred to the next correction data table creation unit 208. The dot recording timing in the inkjet head 3 is corrected according to this characteristic. In other words, when the recording paper conveyance speed is fast, the dot recording timing is correspondingly advanced, and when the conveyance speed is low, the dot recording timing is correspondingly delayed, so that the dot recording timing is correspondingly delayed.

Therefore, the correction data table creating section 208
First, based on the characteristics of the positional deviation amount Δt, the amount of variation in the distance between the marks, that is, the variation amount Δh ′ between the individual marks is calculated. This calculation is a difference process for the distance between the individual points on the curve characteristic. FIG. 6C shows the calculation result of the inter-mark distance variation amount Δh ′ at the rotation angle of the recording paper conveyance roller 5 by this calculation. A timing amount to be corrected (timing correction amount) is obtained based on this characteristic.

The timing correction amount is obtained as follows. The number of dots constituting the sub-scanning direction between a certain marker start line and the next marker start line is several tens of dots (for example, about 40 dots), and this is set as n dots, and the registration mark is set at a constant paper conveyance speed. If the distance between adjacent marker start lines on the assumption that they are recorded is h and the dot distance is hs, h = n · hs
Have a relationship.

Further, dot-to-dot recording timing in the main scanning direction (time from dot recording to next dot recording)
When ts is the reference timing, the printing time between the adjacent marker start lines is nts. Therefore, in order to absorb the distance of Δh ′ temporally when h is displaced by Δh ′, the relation of
It is necessary to add dot output timing correction for t.

That is, the timing correction amount Δt is h + Δh ′: h = nts: n (ts + Δt) From this, Δt = − (Δh ′ / (h + Δh ′)) × ts, and thus Δt is obtained. When the correction data table is created by performing such calculation, it becomes as shown in FIG.

The timing correction amount Δt thus obtained is used to correct the print timing (recording timing) for each dot row position in the sub-scanning direction, so that the dots between dots are printed at the time of printing. As shown in FIG. 7, it is possible to perform dot recording in which the recording timing is controlled to ts + Δt.

Data of Δt for each rotational angle position of the recording paper conveying roller 5 is stored in the correction data table creating section 2
It is obtained at 08, transferred to the correction data unit 204, and stored in the correction data unit 204 as table data.
With this, the data for correcting the print timing corresponding to the periodical conveyance speed fluctuation due to the eccentricity of the recording paper conveyance roller 11 can be set, and thereafter, the recording timing is corrected by using this data. Will be able to do.

Next, the correction of the recording timing using this data will be described.

Inkjet head 3c for the second color
It is assumed that the image recording of is started. Inkjet head 3c
When the image is recorded, first, the recording paper is conveyed by the recording paper conveyance roller 5, and the recording paper conveyance roller 5 is driven by the drive motor 10
Driven by two. The drive motor 102 starts operating when a command signal is transferred from the control unit 101 to the drive circuit 103, and the recording circuit is advanced at a constant speed under the control of the drive circuit of the drive circuit 103.

Similarly to the above, the disk of the rotation detector 201 rotates in accordance with the rotation of the recording paper conveyance roller 5, and when the disk position marker hole passes the photo coupler position by the rotation of the disk, the rotation detector 201 Generates a pulse and sends it to the timing correction unit 202 and the control unit 101.

Receiving the signal, the control unit 101 outputs the reference recording timing signal ts to the timing correction unit 202 so that the ink jet head 3c starts the recording operation. The dot recording timing signal ts from the control unit 101 is a signal for advancing printing for each dot line, and is a signal generated at a constant time interval according to the dot density to be obtained.

In the timing correction section 202, the pulse from the rotation detector 201 is used as a trigger to instruct the address control section 203 to advance the address every time the dot recording timing signal ts is generated from the control section 101 from this point. In the timing correction unit 202, the rotation detector 201
Since the address control unit 203 is reset at the stage of receiving the pulse from the address control unit 203, the address control unit 203 is in a state in which the address can be advanced from the reference address, and thereafter, the address is advanced every time the dot recording timing signal ts is generated. Become.

The address generated from the address control unit 203 is given to the correction data unit 204, and the table data Δt of the correction data unit 204 is read in correspondence with this address. In this way, by reading the table data Δt of the correction data unit 204 in correspondence with the address instructed by the address control unit 203, the correction data corresponding to the rotation angle of the recording paper conveyance roller can be obtained.

This correction data is stored in the timing correction unit 20.
Taken in 2. When the correction data is read by the timing correction unit 202, addition processing is performed to shift the timing by the data value, and a signal is sent to the head control unit 104 at the obtained timing. Head controller 10
When receiving this signal, the inkjet head 3 drives and controls the inkjet head 3 so as to form a dot row in accordance with the image data given from the control unit 101, and the inkjet head 3c causes the image data constituent dots to be formed on the recording paper. Form a corresponding image.

As a result, the dot recording timing is as shown in FIG.
The recording process of the image data is performed by the inkjet head 3c so as to be recorded in the relationship as described above.

In the subsequent recording, as described above, when the position marker of the rotation detector 201 passes the photo coupler position in accordance with the rotation of the recording paper conveyance roller, the timing correction unit 202 and the control unit 101 use a start pulse. The image is transferred and the image recording is started in the sequence of the inkjet head 3c. This operation is performed by the inkjet heads 3m and 3y.
The same process is performed up to image recording.

As a result of such control, as shown in FIG. 8B, the intervals between printed dots become constant,
As shown in FIG. 8 (a), the dots are printed with a feeling that the dots are lined up at a substantially equal interval.

Further, a registration mark for detecting the image recording position may be formed on the edge of the recording paper, and this may be read by a sensor to obtain the recording start timing of each color image. That is,
This is because the fluctuation of the peripheral speed due to the eccentricity from the recording paper conveyance is corrected by the correction table, so that the printing start position can be determined independently of the angular position of the recording paper conveyance roller.

Therefore, according to this method, even if the recording paper expands or contracts, the expansion / contraction correction of the recording paper can be performed separately from the eccentricity correction.

As described above, the registration marks are recorded on the recording paper at regular time intervals, the pitch of the recorded registration marks is measured, and the image forming timing of the ink jet head is adjusted according to the pitch. The dot interval can be made constant by absorbing the change in the conveyance speed of the recording paper due to the eccentricity of the recording paper conveyance roller and the like by the image formation timing control.

[0075]

As described above, according to the present invention, it is possible to form a high-quality color image by eliminating the color shift due to the eccentricity of the recording paper conveying roller and the color unevenness due to the density of the image dots.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a color image recording apparatus in an example of the present invention.

FIG. 2 is a block diagram showing details of a main part of a control system in an example of the present invention.

FIG. 3 is a diagram for explaining a conventional example.

FIG. 4 is a diagram for explaining a conventional example.

FIG. 5 is a diagram for explaining a conventional example.

FIG. 6 is a characteristic diagram for explaining an operation of a main part in an example of the present invention.

FIG. 7 is a timing chart showing dot recording timing in an example of the present invention.

FIG. 8 is a diagram for explaining a dot print state in an example of the present invention.

[Explanation of symbols]

3 is an inkjet head, 5 is a recording paper conveying roller, 1
01 is a control unit, 102 is a drive motor, 103 is a drive circuit, 104 is a head control unit, 201 is a rotation detector, 20
2 is a timing correction unit, 203 is an address control unit, 20
4 is a correction data part, 205 is a marker position detector, 206
Is a line position calculation unit, 207 is a position shift amount calculation unit, 20
Reference numeral 8 is a correction data table creation unit.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2C056 EA07 EA11 EB13 EB35 EB37                       EC37 EC77 EE02 EE03                 2C480 CB02 CB30 CB34 EC04 EC05                 2H030 AA01 AD05 AD11 AD17                 5C072 AA03 BA19 MB09 NA08 QA14                       QA17 RA06 RA07 UA13 UA18                       VA07 XA04                 5C074 AA08 AA10 BB16 DD12 DD15                       EE05 EE08

Claims (4)

[Claims] 1. A recording paper conveying roller for conveying a recording paper, and a color image recording for performing line-by-line printing recording in different colors in the same area on the recording paper when the recording paper is conveyed by the recording paper conveying roller. In the apparatus, the color order of the recording means is k, c, m, and y, the recording mark is recorded on the recording paper at the same time as the registration mark is recorded at a constant time interval, and the reading means reads the registration mark, Calculation means for calculating the moving speed displacement of the recording paper from the read information of the registration mark, and based on the calculated moving speed displacement of the recording paper, the print recording timing of the line-by-line by the recording means of the colors c, m and y. Data creation means for creating the correction data, and the print recording timing of the printing means for the c, m, and y colors is controlled based on the correction data created by the data creation means. Color image recording apparatus characterized by a control means for. 2. The color image recording apparatus according to claim 1, wherein the image recording means is a drop-on-demand inkjet head arranged in a plane. 3. A recording sheet conveying roller for conveying a recording sheet, and a color image recording for performing line-by-line printing recording with different colors in the same area on the recording sheet when the recording sheet is conveyed by the recording sheet conveying roller. In the apparatus, the color order of the recording means is k, c, m, and y, the recording mark is recorded on the recording paper at the same time as the registration mark is recorded at a constant time interval, and the reading means reads the registration mark. Calculation means for calculating the moving speed displacement of the recording paper from the read information of the registration mark, and based on the calculated moving speed displacement of the recording paper, the print recording timing of the line-by-line by the recording means of the colors c, m and y. Data creating means for creating the correction data, and controlling the print recording timing by the printing means for the colors c, m, and y based on the correction data created by the data creating means. In a color image recording apparatus for producing a predetermined output product by a post-processing device or the like using continuous paper as a recording paper for high-speed processing, the registration mark is set in a printing prohibited area. The color image recording apparatus according to claim 1, wherein the color image recording apparatus records. 4. A recording sheet conveying roller for conveying a recording sheet, and a color image recording for performing line-by-line printing recording in different colors in the same area on the recording sheet when the recording sheet is conveyed by the recording sheet conveying roller. In the apparatus, the color order of the recording means is k, c, m, and y, the recording mark is recorded on the recording paper at the same time as the registration mark is recorded at a constant time interval, and the reading means reads the registration mark, Calculation means for calculating the moving speed displacement of the recording paper from the read information of the registration mark, and based on the calculated moving speed displacement of the recording paper, the print recording timing of the line-by-line by the recording means of the colors c, m and y. Data creation means for creating the correction data, and the print recording timing of the printing means for the c, m, and y colors is controlled based on the correction data created by the data creation means. In a color image recording apparatus for producing a predetermined output product by a post-processing device or the like using continuous paper as recording paper for high-speed processing, the registration mark is recorded in the recording paper conveyance direction. 3. The color image recording apparatus according to claim 1, wherein the image is recorded in a print prohibited area between the output products.