JP2001277673A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a conventional ink jet recorder that an appropriate image conditioning can not be carried out due to floating of a print sheet, sheet skew or lowering of carrying accuracy incident to reciprocating carriage using only a sheet carrying roller. SOLUTION: The inkjet recorder performs imaging by ink jet printing onto the surface of a print sheet drawn out by loading a recording medium, i.e., a roll sheet. At the time of image conditioning, a test pattern is printed while clamping a print sheet by means of sheet carrying roller pair and sheet discharging roller pair disposed in the upstream and downstream of a platen, and then that test pattern is read out at an image pickup section in order to determine a correction value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for performing ink jet printing on a recording medium, and more particularly to an ink jet recording apparatus for performing an appropriate image tone after adjusting the apparatus to a carriage such as ink head replacement.

[0002]

2. Description of the Related Art Conventionally, a continuous recording medium wound up in a roll shape, for example, a roll paper (print paper) is loaded, pulled out as needed, and an image is formed on the paper surface by ink jet printing. 2. Description of the Related Art There is an ink jet recording apparatus that separates and discharges paper with a cutter unit.

FIG. 5 shows a simplified sectional configuration of a conventional ink jet recording apparatus.

In this printer, the carriage 21 and the platen 22 are opposed to each other, and a gap through which the print paper 23 passes is arranged between the carriage 21 and the platen 22 to constitute an image forming unit. The platen 22 has a large number of small holes, and a platen chamber 24 and a fan unit 25 for exhausting air are provided on the back side. At the time of printing, the inside of the platen chamber 24 is evacuated by the fan unit 25, so that the printing paper 23 is sucked to the platen 22 side to eliminate irregularities on the paper surface, so that printing without deviation is realized. ing.

A roll paper 26 on which a long print paper 23 is wound is loaded above them (upstream side in the paper transport direction), and a paper feed for sending the paper from the roll paper 26 to the image forming unit is provided. Roller 27 and paper transport roller 2
8 are provided. A cutter unit 29 and a paper discharge roller 30 are provided below the platen chamber 24 (downstream in the paper transport direction). Further, a paper feed sensor 31 is provided on the upstream side of the carriage 21 and the platen 22, and a paper discharge sensor is provided on the downstream side, respectively.
The presence or absence of the print paper 23 is detected.

In such an ink jet recording apparatus, when an ink head or an ink cartridge is exchanged, an image such as a position adjustment of a jet port is adjusted so that inks of respective colors land at the same position and overlap correctly before printing. Adjustment, the so-called "picture tone", is required.

[0007] A normal image tone is obtained by adjusting the printing start position of the printing paper 23 and the alignment of ink droplets of each color.
The loaded roll paper 26 is pulled out, the print paper 23 is placed through the gap between the carriage 21 and the platen 22, and if necessary, the leading end 23a is cut out by the cutter unit 29 and discharged.

Then, the printing paper 23 is placed on the platen 22.
Reciprocating above, for example, mounted on the carriage 21
A predetermined test pattern is printed by ejecting each color of ink such as black (K), cyan (C), and magenta (M), and a correction value is obtained from the degree of the overlap to adjust appropriately.

[0009]

In the image quality of the above-described conventional ink jet recording apparatus, printing is performed by sandwiching the print paper 23 only by the paper transport roller 28 and reciprocating on the platen 22. That is, in FIG. 6, the print paper 23 is nipped by the paper transport roller 28, and the print paper 23 is reciprocated within a range where the leading end does not reach the paper discharge roller 30 to print the test pattern for image adjustment.

As a result, the conveyance accuracy is reduced only by the paper conveyance roller 28, the paper skew occurs, and the print paper 23 is originally drawn from the roll paper 26. Also in the case of attachment, there is a case where lifting is caused by curling due to winding and printing or reading is not performed on a flat paper surface.

As an example of an image tone test pattern, assuming that the print paper 23 is transported in the direction shown by the arrow as shown in FIG. 7, black (K), cyan (C),
When the test patterns for each color of magenta (M) are printed, the landing positions of the black (K) and cyan (C) ink particles coincide with each other and overlap, but the magenta (M) may be shifted. There is a problem that an appropriate image tone cannot be obtained unless it is known whether the shift is a shift to be adjusted or a shift that has occurred simply because the paper feeding is not successful.

That is, when the conveyance accuracy is lowered, the paper skew or the floating of the print paper occurs, if the print paper is conveyed correctly and the paper surface is flat, if the adjustment is performed, the end of the print paper is adjusted. However, the printing deviation is corrected, but the tension is applied when the end of the printing paper is sandwiched between the discharge rollers, the floating is eliminated, and conversely, the printing deviation occurs.

Accordingly, the present invention prints and reads an arbitrary test image in a state where the recording medium is sandwiched between a pair of conveyance rollers and a pair of paper discharge rollers, thereby performing image tone in a highly accurate conveyance state. An object of the present invention is to provide an ink jet recording apparatus capable of obtaining an accurate correction value.

[0014]

In order to achieve the above object, the present invention provides an ink jet recording means for recording an arbitrary test image on a recording medium, and is arranged in a recording area so as to face the ink jet recording means. A platen, a pair of transport rollers disposed upstream of the platen in the recording medium transport direction, a pair of discharge rollers disposed downstream of the platen in the recording medium transport direction, and a test recorded on the recording medium. In the ink jet recording apparatus provided with a scanner for reading an image, an ink jet recording apparatus is provided in which the recording of the test image is performed in a state where the recording medium is sandwiched between the pair of transport rollers and the pair of paper discharge rollers.

[0015] Further, an ink jet recording means for recording an arbitrary test image on a recording medium, a carriage mounted with the ink jet recording means and movable along the width direction of the recording medium, and In an ink jet recording apparatus including a driving unit for reciprocatingly driving along a width direction of the recording medium and a scanner for reading a test image recorded on the recording medium, the driving unit controls a moving speed of a carriage when recording the test image. Provided is an ink jet recording apparatus that makes the moving speed of a carriage slower when recording an ordinary image.

In the ink jet recording apparatus having the above-described structure, an image is formed by ink jet printing on the paper surface of a print sheet pulled out by loading roll paper as a recording medium. When performing image adjustment, the print paper is reciprocated while the print paper is sandwiched between the pair of paper transport rollers and the pair of paper discharge rollers provided upstream and downstream of the platen, and the test pattern is formed by the carriage. A test pattern is read by the printing and imaging unit to determine a correction value.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration example (cross-sectional configuration) of an inkjet recording apparatus according to the present invention, and will be described. In the present embodiment, two rolls of paper 2 (2
a, 2b) is loaded, an image is formed by ink-jet printing on the paper surface of the print paper 1 pulled out from one of the roll papers 2, and the printed portion is cut off by the cutter unit 3 to be discharged. It is a recording device.

In this ink jet recording apparatus, the carriage 4 and the platen 5 face each other,
Are arranged with a gap through which the image passes. The platen 5 is provided with a number of small holes, and is provided with a platen chamber 6 and a suction fan unit 7 for exhausting air on the back side. At the time of printing, the inside of the platen chamber 6 is exhausted by the suction fan unit 7, so that the printing paper 1 is sucked to the platen 5 side to eliminate unevenness on the paper surface, thereby realizing printing without displacement.

The carriage 4 is sandwiched between two linear guide rails 16a and 16b in a direction (printing direction) perpendicular to the transport direction of the print sheet 1, and moves on these guide rails. On the carriage 4, an ink head (not shown) in which a plurality of ejection ports (nozzles) for ejecting ink are arranged has a plurality of ink tanks 15 filled with inks of different colors according to each color. There are several. An ink tank 15 for supplying ink to the ink head is mounted.

Above the carriage 4 and the platen 5 (upstream side in the paper transport direction), the above-described two roll papers 2 are arranged, and a paper feed for sending the papers from these roll papers 2 to the image forming unit is provided. Roller pair 8 (8a, 8
b) and a pair of paper transport rollers 9 are provided, and the transport of the roll paper 2 is performed. A cutter unit 3 is provided below the platen chamber 6 (downstream side in the paper transport direction).
And a discharge roller pair 10 are provided. A paper feed sensor 11 (11a, 11b) is provided on the upstream side of the image forming unit, and a paper discharge sensor 12 is provided on the downstream side.

Further, on the upstream side of the carriage 4, there are provided an image pickup section 13 composed of an image pickup device such as a CCD for reading printed characters and patterns, and an edge sensor 14 for detecting an end of the print paper 1. Is provided. These are driven integrally with the carriage 4.

Next, the image tone in the ink jet recording apparatus according to the first embodiment will be described. As shown in FIG. 1, the leading end of the print paper 1 pulled out from the roll paper 2 is nipped by a pair of discharge rollers 10.
As a result, the print paper 1 is in a state of being sandwiched between the paper transport roller pair 9 and the paper discharge roller pair 10.

Then, as shown in FIG. 2A, a test pattern for performing the image tone described with reference to FIG.
To print. At this time, when the print paper 1 is transported from upstream to downstream, the paper discharge roller pair 10 rotates faster than the paper transport roller pair 9, so that the print paper 1 is transferred to the paper discharge roller pair 10. The tension M is applied by being pulled.

Then, as shown in FIG. 2B, the print paper 1 is once conveyed (rewinded) from downstream to upstream. After rewinding, as shown in FIG. 2 (c), the printing paper 1 is conveyed again from upstream to downstream as shown in FIG. The test pattern is read, processed by a control unit (not shown), and a correction value is obtained.

According to the present embodiment, when printing and imaging the test pattern in the image tone, the tension is activated because the print paper is sandwiched between the paper transport roller pair and the paper discharge roller pair. The transport accuracy is increased, the floating and the like are eliminated, and a correct correction value by proper printing and reading can be obtained.

Next, the image tone in the ink jet recording apparatus according to the second embodiment will be described. The configuration of the present embodiment is equivalent to the configuration shown in FIG. Normally, when the print paper 1 is reciprocated by the paper transport roller pair 9 or the paper discharge roller pair 10, the print paper 1 is transported by the difference in the pressing pressure between the rollers. In some cases, a skew (position shift) may occur. In the embodiment, the skew generated on the print sheet 1 due to the conveyance of the pair of sheet conveyance rollers 9 and the pair of discharge rollers 10 at the time of performing image adjustment is minimized.

First, as in the first embodiment, the printing paper 1 is changed from a state in which the printing paper 1 is sandwiched between the paper conveying roller pair 9 and the paper discharging roller pair 10 as shown in FIG. While transporting 1 from upstream to downstream, a predetermined test pattern is printed by driving the carriage 4. At this time, the paper discharge roller pair 10 rotates faster than the paper transport roller pair 9, and the print paper 1 is pulled by the paper discharge roller pair 10, and the tension by the paper transport roller pair 9 acts.

After the printing, as shown in FIG. 3B, the test pattern is read by the imaging unit 13 while the printing paper 1 is transported from the downstream to the upstream, and is processed by the control unit (not shown). Desired. When the print paper 1 is transported (rewinded) from downstream to upstream in this way, the paper discharge roller pair 10 is stopped in a free state, and the paper transport roller pair 9 is rotated in the reverse direction. As a result, the print paper 1 is pulled by the paper transport roller pair 9 and the discharge roller pair 1
The back tension N (in the opposite direction to the tension M) due to 0 is applied.

According to the present embodiment, the test pattern is printed with a minimum number of times of conveyance by two times of printing and reading in the image tone, so that a shift generated in the conveyance can be minimized.

In this embodiment, the image pickup unit 13 is mounted on the upstream side of the carriage 4. On the other hand, as shown by a dotted line in FIG. If the test pattern printed by the carriage 4 is separately disposed directly below the downstream side of the carriage 4 without being mounted on the carriage 4, the test pattern can be simultaneously read by conveyance during printing. With such a configuration, it is possible to print and read the test pattern in one transfer.
However, in order to obtain an average correction value in the width direction of the print paper 1, the imaging unit 13 'needs to arrange a long line sensor-like imaging device or an imaging device at a plurality of locations. Of course, in the width direction of the print paper 1,
If the distance between the ink head mounted on the carriage 4 and the printing paper 1 is constant, it can be realized by one imaging unit.

Next, with reference to FIG. 4, an image tone in the ink jet recording apparatus according to the third embodiment will be described. The configuration of the present embodiment is equivalent to the configuration shown in FIG. In the present embodiment, the deviation of the mounting angle of the ink head to the carriage 4 around the axis perpendicular to the paper surface of the print paper 1 is properly adjusted.

In an ink head (not shown) in which a plurality of ejection ports are arranged in a line, if there is a difference in ejection speed between these ejection ports, ink is ejected from the ink head of the moving carriage 4. When printing, the ink droplet ejected from the ejection port having a strong ejection force of the ink droplet has a high ejection speed and lands in a minus direction (rightward in FIG. 4) from the desired position. The ink droplet ejected from the weak ejection port has a slow ejection speed and lands in a positive direction (leftward in FIG. 4) from the desired position.
For example, in the case of an ink head in which the ink ejection force gradually weakens from the upper ejection port to the lower ejection port, as shown in FIG. The added pattern B is printed. For this reason, the angle adjustment of the ink head may not be performed properly.

Accordingly, in printing the test pattern for adjusting the angular displacement of the ink head, the printing speed is set to a value lower than the normal printing speed or to stop the printing, thereby causing a difference in the ejection speed of the ink head. However, the influence on the angle adjustment of the ink head can be suppressed.

In the movement of the carriage 4 as shown in FIG. 1, when moving from the moving state to the target printing position, when reaching the target position and stopping, and when reversing reciprocating printing, Since a motor is used for driving the carriage, overshoot occurs. This overshoot is caused by the response and the gain.If the gain is increased, the response becomes faster, but there is a problem that it takes time for the vibration due to the overshoot to stop. Accept. Therefore, when printing the test pattern at the time of image tone, instead of printing from the end of the print sheet 1, the position where the overshoot has disappeared is determined by considering the length where the overshoot has disappeared. Must be determined as Further, when it is desired to start stable printing from the end of the print sheet, it can be realized by moving the print sheet away from the end of the sheet by the length of the overshoot.

Although the above embodiments have been described, the present invention includes the following inventions.

(1) Ink jet recording means for recording an arbitrary test image on a recording medium, and a platen arranged in the recording area so as to face the ink jet recording means;
A pair of transport rollers disposed upstream of the platen in the recording medium transport direction, a pair of discharge rollers disposed downstream of the platen in the transport direction of the recording medium, and reading a test image recorded on the recording medium. And a scanner, wherein the recording of the test image is performed in a state where the recording medium is sandwiched between the pair of transport rollers and the pair of paper discharge rollers.

(2) Detecting means for detecting that the recording medium has been conveyed to the extent that it is nipped by the pair of paper discharge rollers is provided, and a test image is recorded in accordance with the output detected by the detecting means. (1) characterized in that:
Item 6. The ink jet recording apparatus according to item 1.

(3) Ink jet recording means for recording an arbitrary test image on a recording medium, and a platen arranged in the recording area to face the ink jet recording means;
A pair of transport rollers disposed upstream of the platen in the recording medium transport direction, a pair of discharge rollers disposed downstream of the platen in the transport direction of the recording medium, and reading a test image recorded on the recording medium. And a scanner, wherein reading of the test image by the scanner is performed in a state where the recording medium is sandwiched between the pair of transport rollers and the pair of paper discharge rollers.

(4) Detecting means for detecting that the recording medium has been conveyed to the extent that it is nipped by the pair of paper discharge rollers is provided, and a test image is read in accordance with the output detected by the detecting means. The ink jet recording apparatus according to the above mode (2).

(5) The recording medium conveying force is set such that the conveying roller pair and the paper discharging roller pair apply tension to the recording medium to such an extent that the recording medium does not rise above the platen. The ink jet recording apparatus according to the above (1) and (2), wherein

(6) Ink jet recording means for recording an arbitrary test image on a recording medium, a carriage mounted with the recording means and movable in a direction perpendicular to the conveying direction of the recording medium, and a recording area. A platen arranged to face the ink jet recording means, a pair of transport rollers arranged upstream of the platen in the recording medium transport direction, and a discharge roller arranged downstream of the platen in the recording medium transport direction A pair, mounted on the carriage,
A scanner that reads a test image recorded on the recording medium; and an inkjet recording apparatus comprising: a recording unit that performs recording of the test image when the recording medium is transported from an upstream side in a paper transport direction to a downstream side. An inkjet recording apparatus according to claim 1, wherein the reading of the test image is performed when the recording medium is conveyed from a downstream side to an upstream side in a sheet conveying direction.

(7) Ink jet recording means for recording an arbitrary test image on a recording medium, and a platen arranged in the recording area so as to face the ink jet recording means;
A pair of transport rollers disposed upstream of the platen in the recording medium transport direction, a pair of discharge rollers disposed downstream of the platen in the recording medium transport direction, and a downstream of the inkjet recording unit in the recording medium transport direction. A scanner that is arranged on the side and reads a test image recorded on the recording medium,
An ink jet recording apparatus comprising: performing a recording of a test image and a reading of a test image during a conveying process from an upstream side to a downstream side in a conveying direction of the recording medium.

(8) Ink jet recording means for recording an arbitrary test image on a recording medium, a carriage mounted with the ink jet recording means and movable along the width direction of the recording medium, and In an ink jet recording apparatus comprising: a driving unit for reciprocatingly driving the recording medium in a width direction thereof; and a scanner for reading a test image recorded on the recording medium, the driving unit includes a driving unit that moves the carriage when the test image is recorded. An ink jet recording apparatus, wherein the moving speed is lower than the moving speed of a carriage when recording a normal image.

(9) The ink jet recording apparatus according to the above mode (8), wherein the recording of the test image is performed with the carriage stopped.

[0045]

As described above in detail, according to the present invention, an arbitrary test image is printed and read in a state where the recording medium is sandwiched between the pair of conveying rollers and the pair of paper discharging rollers, thereby achieving high accuracy. It is possible to provide an ink jet recording apparatus capable of performing image tone in a high conveyance state and obtaining an accurate correction value.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram showing a schematic configuration example of an inkjet recording apparatus of the present invention.

FIG. 2 is a diagram for describing an image tone in the ink jet recording apparatus according to the first embodiment.

FIG. 3 is a diagram for explaining an image tone in an ink jet recording apparatus according to a second embodiment.

FIG. 4 is a diagram for explaining an image tone in an ink jet recording apparatus according to a third embodiment.

FIG. 5 is a diagram showing a simplified cross-sectional configuration of a conventional inkjet recording apparatus.

FIG. 6 is a diagram for explaining image quality in a conventional ink jet recording apparatus.

FIG. 7 is a diagram illustrating an example of a test pattern for image tone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Print paper 2, 2a, 2b ... Roll paper 3 ... Cutter unit 4 ... Carriage 5 ... Platen 6 ... Platen chamber 7 ... Suction fan part 8 ... Sheet roller pair 9 ... Paper transport roller pair 10 ... Discharge roller pair DESCRIPTION OF SYMBOLS 11 ... Feed sensor 12 ... Discharge sensor 13 ... Imaging part 14 ... Edge sensor

Claims (3)

[Claims] 1. An ink jet recording means for recording an arbitrary test image on a recording medium, a platen disposed in a recording area so as to face the ink jet recording means, and a platen disposed upstream of the platen in a recording medium transport direction. And a scanner that reads a test image recorded on the recording medium, and a scanner that reads a test image recorded on the recording medium. The image recording is performed in a state where the recording medium is sandwiched between the pair of conveying rollers and the pair of discharging rollers. A detecting means for detecting that the recording medium has been conveyed to such an extent that the recording medium is nipped by the discharge roller pair, and recording a test image in accordance with an output detected by the detecting means. The ink jet recording apparatus according to claim 1, wherein: 3. An ink jet recording means for recording an arbitrary test image on a recording medium, a carriage mounted with the ink jet recording means and movable along a width direction of the recording medium, and A driving unit for reciprocatingly driving along a width direction of the recording medium; and a scanner for reading a test image recorded on the recording medium, wherein the driving unit moves the carriage at the time of recording the test image. An ink jet recording apparatus wherein the speed of the carriage is made slower than the moving speed of the carriage when recording a normal image.