JP2001121717A - Ink-jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce occurrence of image non-uniformity in the case of wiping the ejection opening surface during recording so as to prevent deterioration of the image quality without lowering the throughput of the recording device nor the ink ejection reliability. SOLUTION: This device comprises a dot counting means for estimating the wet state of an ejection opening surface, an ink amount detecting means for detecting the ink amount per unit area to be provided on a recording paper in the next recording scanning area, and a wiping operation determining means for determining whether or not the ejection opening surface should be wiped before recording scanning according to the value counted by the dot counting means, and the detection value by the ink amount detecting means.

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 recording by discharging ink from a recording means to a recording material, and more particularly to an ink jet recording apparatus provided with a wiping means for cleaning a discharge port surface of the recording means. It relates to a recording device.

[0002]

2. Description of the Related Art A recording device having functions such as a printer, a copying machine, and a facsimile, or a recording device used as an output device of a composite electronic device or a workstation including a computer and a word processor, etc., is based on image information. It is configured to record an image on a recording material (recording medium) such as a plastic thin plate. The recording apparatus can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type and the like according to a recording method.

In a serial type recording apparatus employing a serial scanning system in which a main scanning is performed in a direction crossing a conveying direction (sub-scanning direction) of a recording material, the recording material is set at a predetermined recording position, and then the recording is performed. The image is recorded (main scanning) by the recording means mounted on the carriage moving along the material, and after the recording of one line is completed, a predetermined amount of paper feeding (pitch conveyance) is performed, and then the stopped image is stopped again. By repeating the operation of recording (main scanning) the next row of image on the recording material, the entire recording material is recorded. On the other hand, in a line type recording apparatus that records only by sub-scanning in the transport direction of the recording material, the recording material is set at a predetermined recording position, and recording is performed for one line at a time. Is performed, and the recording of the next line is performed collectively, thereby recording the entire recording material.

Among the above recording apparatuses, an ink jet recording apparatus (ink jet recording apparatus) performs recording by discharging ink from a recording means (recording head) onto a recording material. Easy,
High-definition images can be recorded at high speed, recording can be performed on plain paper without special processing, running costs are low, and the non-impact method reduces noise, and It has advantages such as easy recording of a color image using ink. Above all, a line-type apparatus using a line-type recording means in which a large number of discharge ports are arranged in the paper width direction can further increase the recording speed.

[0005] In particular, an ink jet type recording means (recording head) for discharging ink by using thermal energy,
Through a semiconductor manufacturing process such as etching, vapor deposition, sputtering, etc., an electrothermal converter, an electrode,
By forming the liquid path wall, the top plate, and the like, it is possible to easily manufacture a device having a high-density liquid path arrangement (discharge port arrangement) and achieve further downsizing. On the other hand, there are various requirements for the material of the recording material,
In recent years, ordinary recording materials such as paper and resin thin plates (OHP
Etc.), thin paper and processed paper (paper with perforated holes or perforated paper for filing, paper of any shape, etc.) have been required to be used.

In an ink jet recording apparatus, since ink droplets are ejected from a recording head onto a recording material for recording, fine ink droplets (mists) generated in addition to the main ejected ink droplets (main droplets) and recording are performed. Ink may adhere to the ejection port surface of the recording head due to scattered ink droplets generated by the rebound of the ink droplets ejected to the material. If a large amount of the ink thus adhered gathers around the ejection port of the recording head, or if foreign matter such as paper dust adheres to the ink thus gathered, ink ejection from the ejection port is obstructed, and ink droplets are disturbed. However, an ejection failure such as flying in an unexpected direction or an ink droplet not being ejected occurs.

Therefore, in order to solve such a problem,
In a conventional ink jet recording apparatus, a rubber is used as a means for cleaning and removing foreign matter such as unnecessary ink and paper powder adhered to a discharge port surface of a recording head due to ink mist or rebound of ink droplets from a recording material. A mechanism for wiping and cleaning the discharge port surface by relatively moving a blade formed of an elastic member such as the above and the discharge port surface of the recording head in contact with each other is provided. The wiping operation in this case is an important technique for improving the reliability of the ink jet recording apparatus. Further, as a means for removing foreign matter and the like in the discharge port that cannot be completely removed by the wiping operation, a suction recovery mechanism including a cap covering the discharge port surface and a suction pump connected to the cap is also provided. In the recovery operation by the suction recovery mechanism, the ink is forcibly sucked out of the ejection openings of the recording head by the negative pressure generated by the suction pump, thereby discharging the foreign substances such as the thickened ink and bubbles in the ejection openings. This is to refresh the ink in the ejection openings, thereby restoring a normal ejection state.

In the wiping operation of the conventional ink jet recording apparatus, control is executed in accordance with the recording time, or control is executed in accordance with the number of dots of ink droplets ejected from the recording head (the number of recording dots). Furthermore, a control or the like in which these are combined is employed. Normally, the wiping operation is set so as to be executed before the wetting of the ink adhered to the ejection opening surface of the print head causes ejection failure. For example,
JP-A-7-125228 discloses a technique in which the number of recording dots and the recording time are measured, and the timing of a wiping operation during recording is controlled based on the measured number of recording dots and the recording time.

[0009]

However, recording is carried out while reciprocating (main scanning) a carriage equipped with a recording head having a plurality of ejection ports arranged in a direction crossing the conveying direction (sub-scanning direction) of the recording material. In a serial type ink jet recording apparatus, if a wiping operation is performed during the recording, the recording density or color of a recording portion immediately after the wiping operation changes, and as a result, a phenomenon that density unevenness or color unevenness occurs in a printed image. The inconvenience of appearing may occur. Such non-uniform density is recorded by using a multi-pass printing method (also called a fine printing method) in which a plurality of ink dots are overprinted in the same pixel or a certain image is formed by a plurality of printing scans. This is likely to occur if a wiping operation is performed during the operation.

This phenomenon is caused by the fact that if printing is performed under a carriage operation with a constant rhythm, the penetration of ink into the recording material becomes constant in all the recorded image areas and the image density does not change. If the constant rhythm of the carriage operation is disrupted by the wiping operation, the permeation state of the ink into the recording material in that part also changes, so that a density change or a color change occurs in that part. This is a phenomenon in which a change in density or a change in color is visually perceived as unevenness. The easiness of the detection of the unevenness differs depending on the recorded image, and the unevenness tends to be easily detected in an image having a high recording dot density, and the unevenness tends to be inconspicuous in an image having a low recording dot density.

The present invention has been made in view of such technical problems, and an object of the present invention is to reduce the occurrence of unevenness in an image due to wiping during recording.
Without reducing the throughput of the recording device,
An object of the present invention is to provide an ink jet recording apparatus capable of performing recording without lowering the reliability of ink ejection.

[0012]

According to a first aspect of the present invention, there is provided an ink-jet recording apparatus which performs recording by discharging ink from a recording means onto a recording material to achieve the above object.
A wiping unit for cleaning the ejection port surface of the recording unit, and whether or not to perform a wiping operation before the printing scan based on the amount of ink per unit area applied to the recording material in the next printing scan area And a wiping operation determining unit for determining the wiping operation.

According to a second aspect of the present invention, there is provided an ink jet recording apparatus which performs recording by discharging ink from a recording means to a recording material in order to achieve the above object. Means, counting means for estimating the state of wetting of the ejection port surface of the recording means, and ink amount detecting means for detecting the amount of ink per unit area applied to the recording material in the next printing scan area And wiping operation determining means for determining whether or not to perform a wiping operation before printing scan based on the count value of the counting means and the detection value of the ink amount detecting means.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the counting means is a dot counting means for counting the number of ink ejection dots, or the counting means counts a recording time. The above-mentioned object is achieved more efficiently by adopting a configuration that is a time counting means that performs the above-mentioned operations.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially broken perspective view showing a schematic configuration of an embodiment of an ink jet recording apparatus to which the present invention is applied. In FIG. 1, a head cartridge 1 as a recording unit is mounted on a carriage 2, and the head cartridge 1 has four head cartridges (recording unit, recording head, ) 1A, 1B, 1C, and 1D. In the following description, the recording means 1A to 1D
Is simply referred to as recording means (recording head, head cartridge) 1.
Each of the head cartridges 1 has an ink tank section at the top,
A print head unit (ink ejection unit) is provided below, and a connector unit (not shown) for receiving a signal for driving the print head unit and the like is provided.

The carriage 2 has the four head cartridges 1A, 1B, 1C, and 1D positioned and exchangeably mounted thereon, and further receives signals for driving the recording head of each head cartridge. A connector holder (not shown) for transmission is provided. This connector holder is electrically connected to each recording head 1. The tanks of the plurality of head cartridges 1 contain inks of different colors, for example, yellow, magenta, cyan, and black inks. Each head cartridge 1 discharges these inks. It is configured to record.

The carriage 2 is guided and supported so as to be able to reciprocate along a guide shaft 3 installed in the apparatus main body so as to extend in the main scanning direction. The carriage 2 is driven by a main scanning motor 4 as a driving source via a transmission mechanism including a motor pulley 5, a driven pulley 6, and a timing belt 7, and its position and reciprocation are controlled. The recording material 8 such as paper is transported by a pair of transport rollers 9, 10, 11 and 12 arranged before and after the recording position.
The recording head 1 is conveyed through a position (recording unit) opposed to the ejection port surface. The recording material 8 has its back surface supported by a platen (not shown) so as to form a flat recording surface in the recording section. The recording head of each head cartridge 1 mounted on the carriage 2
An upstream transport roller 10 that projects downward from the carriage 2
, And the discharge port surface thereof is opposed to the recording surface of the recording material 8 with a predetermined gap.

The recording means (head cartridge, recording head) 1 is an ink jet recording means having an electrothermal converter for generating thermal energy used for discharging ink, and further comprises the electrothermal converter. This is an ink jet recording means for discharging ink from a discharge port using film boiling generated in ink by thermal energy generated by a body.

FIG. 2 is a partial perspective view schematically showing the structure of the ink ejection section of each of the head cartridges (recording means, recording head) 1. In FIG. 2, a plurality of discharge ports 22 are formed at a predetermined pitch on a discharge port surface 21 facing the recording material 8 at a predetermined interval (for example, about 0.3 to 2.0 mm). An electrothermal converter (heating resistor, etc.) 25 that generates energy for ink ejection is arranged along the wall surface of each liquid path 24 that connects the liquid chamber 23 and the ejection port 22. In this example, the recording head 1 is mounted on the carriage 2 in a positional relationship such that the rows of the ejection ports 22 are arranged in a direction crossing the main scanning direction of the carriage. Then, the recording head 1 generates thermal energy in the electrothermal transducer 25 by applying a drive signal, and the thermal energy causes the ink in the liquid path 24 to boil, and the pressure generated by the growth and shrinkage of the bubble. Is configured to eject and record ink droplets.

In the ink jet recording apparatus shown in FIG.
The home position of the carriage 2 is set on the left side of the drawing, and the recovery unit 14 is located near the home position.
Are arranged. The recovery system unit 14 includes a discharge port surface 21 of each head cartridge 1 at the home position.
The four caps 15 are provided which can move up and down in the vertical direction at positions corresponding to the above, and which can ascend and come into close contact with the respective discharge port surfaces 21 so that the discharge ports 22 can be sealed (capping possible). . The cap 15 is for capping the discharge port surface 21 of each recording head 1 to prevent drying and evaporation of ink (thickening and sticking of ink) and adhesion of foreign matter such as dust near the discharge port 22. is there. Each of the caps 15 is connected to a suction pump 16 to perform a suction recovery operation for discharging ink from the discharge port 22 by operating the suction pump in a capping state. This suction recovery operation refreshes the ink in the discharge port by discharging the thickened / fixed ink and bubbles in the discharge port 22 together with the ink, thereby restoring and maintaining the ink discharge performance to a normal state. Is a processing operation.

In FIG. 1, a blade 18 as a wiping member held by a blade holder 17 is disposed in the recording area side portion of the recovery system unit 14.
The blade 18 uses the relative movement with respect to the carriage 2 to move the ejection port surface 2 of each recording unit (head cartridge) 1.
1 is for wiping and cleaning (cleaning), and is formed of an elastic member such as rubber. The blade 17 as a wiping member is made of a material having a lower hardness than the recording head 1 so as not to damage the ejection port surface 21. Further, in order to increase the tolerance for the relative positional relationship between the blade 18 and the recording head 1, the blade 18 is often made of an elastic member.

The material used for the blade 18 is an elastic material such as natural rubber, nitrile rubber, butadiene rubber, chloroprene rubber, butyl rubber, chlorinated butyl rubber, silicon rubber, polystyrene rubber, polyvinyl chloride, and polyurethane rubber. Commonly used. Also,
In addition, a foam or a sintered body such as polyurethane or polyethylene may be used. In the present embodiment, the blade 18 supported by the blade holder 17 is advanced by a blade elevating mechanism (not shown) driven by the movement of the carriage 2 to wipe the ink adhered to the ejection port surface 21 of the recording head 1 ( The print head 1 can be moved between a raised position (wiping position) and a retracted (down) position (standby position) so as not to interfere with the ejection opening surface 21 of the recording head 1.

In the present embodiment, when the carriage 2 moves to the cap position at the home position on the left side in the figure, the blade 18 moves forward (rises) to the wiping position, and the carriage 2 moves from the cap position to the recording area side. When the blade 18 moves rightward in the drawing, the blade 18 relatively moves while abutting on the discharge port surface 21 of the recording head unit, thereby performing a wiping operation. Further, the carriage 2 moves to the recording area side and the blade 18
When the blade 18 deviates from 1, the blade 18 descends to a retracted position (standby position) that does not interfere with the discharge port surface 21.

It should be noted that, depending on the ink jet recording apparatus, ink may evaporate and dry at the discharge port where ink is not continuously discharged for a certain period of time, resulting in deterioration of discharge performance and deterioration of image quality of a recorded image. . Therefore, in order to prevent this, an ink jet recording apparatus generally discharges ink from a discharge port 22 at a predetermined place at a certain time interval irrespective of print data, and discharges ink in the discharge port 22. By doing so, a preliminary ejection operation for making the ink fresh is performed. For this reason, the inkjet recording apparatus is sometimes provided with a preliminary ejection receiving unit (not shown) for receiving the ink discharged (ejected) in the preliminary ejection operation.

FIG. 3 is a block diagram illustrating the configuration of a control system of an embodiment of an ink jet recording apparatus to which the present invention is applied. In FIG. 3, reference numeral 41 denotes an interface for inputting a recording signal; 42, a microprocessor unit (MPU); 43, a program ROM for storing a control program executed by the MPU 42; This is a DRAM for storing various data such as recording data supplied to the head 1. The DRAM 44 can store (count) the number of recording dots, the recording time, and the like. A gate array 45 controls supply of print data to the print head 1 and is configured to control transfer of data between the interface 41, the MPU 42, and the DRAM 44.

In FIG. 3, reference numeral 4 denotes a carrier motor (main scanning motor) for conveying the carriage 2 on which the recording head 1 is mounted, and reference numeral 20 denotes a conveying motor for conveying the recording material 8 such as recording paper. is there. 46 is a head driver for driving the recording head 1, 47 is a motor driver for driving the transport motor 20, 48 is a motor driver for driving the carrier motor (main scanning motor) 4, Reference numeral 49 denotes a sensor group for performing various types of detection. The sensor 49 is, for example, a sensor that detects the presence or absence of a recording material (paper or the like) 8, a sensor that detects that the carriage 2 is at the home position, a temperature sensor that detects the temperature of the recording head 1, and the like. Thereby, the presence or absence of the recording material 8, the position of the carriage 2, the environmental temperature, and the like can be recognized.

In FIG. 1 and FIG. 3, when recording data is sent from the host via the interface 41, the recording data is temporarily stored in the DRAM 44 through the gate array 45. Thereafter, the data in the DRAM 44 is converted from the raster data into an image image to be recorded by the recording head 1 by the gate array 45 and stored in the DRAM 44 again. The data is again sent to the recording head 1 by the gate array 45 via the head driver 46, and the recording is performed by discharging ink from the discharge port at the corresponding position. At this time, a counter for dots to be recorded in the gate array 45 is configured so that dots to be recorded can be counted at high speed.

The carrier motor (main scanning motor) 4 is operated via the motor driver 48, and the recording head is moved in the main scanning direction in accordance with the recording speed of the recording head 1, thereby performing recording in the main scanning. When the printing of the main scanning is completed, the motor driver 47 for the transport motor
The recording medium 8 is conveyed (paper feed) at a predetermined pitch in a conveying direction (sub-scanning direction) crossing the main scanning direction by operating the conveying motor 20 via the. Then, in order to print the next line, the carrier motor (main scanning motor) 4 is operated again via the motor driver 48, and the print head 1 is printed.
The recording head is moved in the main scanning direction in accordance with the recording speed of (i), and recording in the main scanning (main scanning of the next line) is performed. Hereinafter, by repeating these operations, recording on the entire recording material 8 is performed.

This embodiment includes a counter for counting the total number of dots ejected after the previous wiping operation, and a counter for separately counting the printing ratio in each printing scan. Therefore, a method of detecting the print ratio in each print scan will be described below.
In counting the recording ratio during one scan (during one main scan), simply counting the total number of dots to be printed in one scan will result in, for example, a case where dots are evenly distributed over one line and a case where local dots are locally distributed. In some cases, dots are densely arranged, and these cannot be distinguished and processed.

FIGS. 4A and 4B are explanatory diagrams illustrating the locality of the recording ratio during one scan. FIG. 4A shows a case where the recording dots are arranged with a uniform duty, and FIG. FIG. 7 is a diagram showing a case where the power supply is arranged with a relatively high duty. In FIG. 4, (a) and (b) show a case where the total number of dots to be recorded in an area of 48 dots vertically and arranged in a 1500-dot horizontal area is 7200 dots, and FIG. In the area, dots are uniformly arranged at a duty of 10%. In FIG. 7B, 7200 dots are concentrated and arranged in an area of 48 dots vertically and 150 dots horizontally in the recording area. I have. Therefore,
FIG. 4B shows a recording ratio of 100 in a local area.
However, the recording ratio is 10% for an area of 48 dots vertically and 1500 dots horizontally as in FIG. 4A. When recording is performed at a relatively low recording ratio as a whole as shown in FIG. 4A, unevenness is not noticeable even when wiping is performed in the middle, but as shown in FIG. If the wiping is performed in the middle of the portion where there is, the unevenness of the recorded image may be conspicuous.

FIG. 5 is an explanatory diagram showing an example of a unit area for calculating a recording ratio in an ink jet recording apparatus to which the present invention is applied. In the embodiment shown in FIG.
A unit area for detecting a recording ratio is provided, whereby a region of one line (one line) by main scanning is divided into a plurality of unit regions, and the recording ratio is counted in each of the divided regions. It is configured to work.
In FIG. 5, the number of ejection ports for each color (each recording head 1) is 48, each unit area is an area of 48 dots by 48 dots, and each unit area is numbered and distinguished. . The total number of dots in this unit area is 48 × 48 =
This is 2304 dots, and the value obtained by recording 2304 dots in this unit area is calculated as a recording ratio of 100%. One of the determinations as to whether or not to perform wiping of the ejection port surface 21 of the print head 1 is to determine whether or not even one unit area having a print ratio exceeding a predetermined value exists in the print area of one main scan. It is based on crab. The size of the unit area is not particularly limited to the above-described size, and may be divided in the ejection port row direction.

FIG. 6 is a flowchart showing one embodiment of a control mode of the wiping operation at the time of printing in the ink jet printing apparatus to which the present invention is applied. In FIG. 6, in the present embodiment, it is determined whether or not wiping is performed at each scan recording, and if the wiping condition is satisfied, the wiping operation is performed before performing the next scan recording. To do. In addition, it is configured to determine whether or not to execute wiping even after the sheet is discharged, and to perform the wiping operation after the sheet is discharged if the wiping condition is satisfied.

FIG. 6 is a flowchart showing a control sequence of the wiping operation in the first embodiment of the ink jet recording apparatus to which the present invention is applied. The wiping operation of the ink jet recording apparatus according to the present invention will be described with reference to FIG. In FIG. 6, when a recording start command is first received, the cap 15 is released from the recording head 1 (step S100), and a wiping operation is performed (step S100).
105). At this time, each recording head (recording head of each color)
The total dot number counter for each recording head 1 is reset, the counting of the total number of recording dots is started for each recording head 1 (step S110), and the recording material 8 such as recording paper is fed (step S115).

Next, the count value Nd of the dot counter of the total recording dot number of each recording head 1 is checked (step S120). In other words, in step S120, the number of dots Nwipl for performing wiping, which is set in advance, is compared with the count value Nd. If there is at least one recording head satisfying Nd ≧ Nwip1, the process proceeds to step S125.
If not, the flow advances to step S140 to execute printing by the next scan (main scan). In step S125,
It is checked whether or not there is a unit area where the print ratio exceeds 25% for each print head 1. If there is any unit area where the print ratio exceeds 25%, the process proceeds to step S140 to perform the next print scan. If there is no unit area exceeding 25%, the wiping operation of each recording head 1 is executed (step S13).
0), the total dot number counter of each print head 1 is reset and restarted (step S135), and then the next print scan (printing by the next main scan) is performed in step S140.
Execute

Next, in step S145, it is determined whether or not recording for one page has been completed. If recording for one page has been completed, the recording paper (recording material) 8 is discharged (step S15).
0). On the other hand, when the recording of the page is not completed yet and the recording is continued, the operations of the above steps S120 to S145 are repeated. After the recording paper on which the recording of one page has been completed is discharged, the recording ratio is always 0%.
At 155, the count value Nd of the dot counter of the total print dot number of each print head 1 is checked, and this count value N
d is the number of dots Nw for performing the preset wiping
If there is at least one recording head 1 larger than ipl, that is, if there is at least one recording head satisfying Nd ≧ Nwip1, the process proceeds to step S160 to perform the wiping operation by the wiping unit. Proceeding to S165, the dot counter is reset and the wiping flag is also reset.

On the other hand, if the total number of dots (Nd) does not exceed the predetermined value (Nwip1) in step S155, the wiping operation is not performed and the process proceeds to step S155.
Proceeding to 170, it is determined whether or not there is print data. If there is print data, the flow returns to step S115 to feed paper, and the above-described printing operation is executed. If the recording data has not been sent in step S170, it is made to stand by at the recording standby position or to close the cap at the home position and wait until the next recording signal is sent.

According to the embodiment described above, the recording means 1
In an ink jet recording apparatus that performs recording by discharging ink from a recording medium to a recording material 8, a discharge port surface 21 of the recording unit is used.
Wiping means 18 for cleaning the recording medium, and counting means for estimating the wet state of the discharge port surface of the recording means (steps S110, S120, S155)
And an ink amount detecting means (step S125) for detecting an ink amount per unit area (recording ratio of the unit area) applied to the recording material 8 in the next printing scanning area; and a count value Nd of the counting means. Wiping operation determining means for determining whether or not to perform a wiping operation before printing scan based on the detected value of the ink amount detecting means (recording ratio of the unit area). By performing the wiping operation within the frame at the time of low-duty printing scan in which image unevenness is unlikely to occur, it is possible to reduce the image unevenness due to the wiping operation and to prevent image deterioration. can get.

FIG. 7 is a flowchart showing a control sequence of the wiping operation in the second embodiment of the ink jet recording apparatus to which the present invention is applied. In the case of the first embodiment shown in FIG. 6, for example, when an image having a high recording ratio is printed on the entire surface of one page, the wiping operation may not be performed even if the total number of dots is larger than the threshold value Nwip1. Therefore, in the present embodiment, as shown in FIG.
5, the count value Nd of the total print dot number counter of each print head 1 is checked, and the count value N
Step S118 of comparing d with another predetermined threshold value Nwip2 of the number of dots for performing wiping.
Has been additionally inserted. Then, this step S118
In step S130, if there is at least one print head satisfying Nd ≧ Nwip2, the process proceeds to step S130, and the wiping operation of the ejection port surface 21 is performed.
20 and the number of dots Nwipl and the count value N for performing preset wiping as in the first embodiment.
d. The second embodiment of FIG. 7 is different from the first embodiment of FIG. 6 in the above points, and has substantially the same configuration in other points.

That is, also in the second embodiment of FIG. 7, if there is at least one recording head satisfying Nd ≧ Nwip1 in step S120, the process proceeds to step S125, and the unit area where the recording ratio exceeds 25% for each recording head 1 It is configured to check whether or not there is, and if not, proceed to step S140 to execute printing by the next scan (main scan), and thereafter, configure to have the same flow as in the first embodiment. ing. Therefore, in the second embodiment of FIG. 7, the same parts as those of the first embodiment of FIG. 6 are denoted by the same reference numerals, and the detailed description thereof will be omitted.

In the second embodiment shown in FIG. 7, as described above, if there is at least one recording head satisfying Nd.gtoreq.Nwip2 in step S118, the flow advances to step S130 to proceed to step S130.
Is performed, otherwise, the process proceeds to step S120, and thereafter the flow is the same as in the first embodiment. At this time, the threshold value Nwip2> the threshold value Nwip1 is set, and the value of the threshold value Nwip2 prevents the ink discharge direction from becoming unstable due to the ink mist attached to the discharge port surface 21 of the recording head 1, and the ink discharge direction. It is a value that can prevent defects and the like, and it is preferable to set the value as high as possible.

In the flowcharts of the embodiments shown in FIGS. 6 and 7, the total dot count value and the value of the recording ratio are described as one for convenience of explanation. In an ink jet recording apparatus using a recording head, a dot counter is prepared for each ink color or each recording head, and checking of a total dot count value and comparison with a recording ratio threshold are performed for each ink color or each recording head. The determination may be made by executing the process every time. Alternatively, an optimum value may be set by integrating all the dot count numbers of the plurality of print heads or calculating the print ratio from all the ink dots ejected from the plurality of print heads. Further, when the degree of conspicuousness of image unevenness varies depending on the characteristics of penetration of ink into a recording material (paper, etc.) and color characteristics, the total dot count value and the threshold value of the recording ratio are set for each ink color or recording head. Different values may be set.

Further, instead of simply counting the number of dots, the number of dots is weighted by the temperature of the print head or the environmental temperature, weighted by the print duty, or converted from the number of dots into a certain value and counted. A threshold may be provided for these values. Further, in each of the above embodiments, the estimation of the wetting amount of the ejection port surface of the recording head is performed by counting the total dot count,
However, the present invention is not limited to this, and the determination may be made based on the number of scans of the print head, the print time, and the like.

In the above embodiment, a serial recording method in which recording is performed while the recording head 1 is relatively moved with respect to the recording material has been described as an example. However, the present invention is not limited to the entire width or a part of the recording material. It can be applied to various inkjet recording devices regardless of the type of recording method, such as a line recording method that records only by sub-scanning using a line type recording head that covers the same length, and achieves the same effect. Can be done.

The present invention also provides a color recording apparatus using a plurality of recording heads for recording with inks of different colors.
A recording apparatus using a plurality of recording heads, a gradation recording apparatus using a plurality of recording heads for recording the same color at different densities,
Alternatively, as long as an ink jet recording apparatus, such as a recording apparatus in which the color recording apparatus and the gradation recording apparatus are combined, it can be widely applied regardless of the form of the recording apparatus,
A similar effect can be achieved. Further, the present invention uses a replaceable inkjet cartridge (head cartridge) in which a printhead and an ink tank are integrated, a structure in which the printhead and the ink tank are separated, and the space between them is connected by an ink supply tube or the like. Such,
The present invention can be similarly applied to any arrangement of the recording head and the ink tank, and the same effect can be obtained.

The present invention can be similarly applied to a case where the ink jet recording apparatus uses another type of ink jet recording means such as an ink jet recording means using an electromechanical transducer such as a piezo element. The same effect can be obtained.

[0046]

As is apparent from the above description, according to the first aspect of the present invention, in an ink jet recording apparatus for performing recording by discharging ink from a recording means to a recording material, the discharge port surface of the recording means is changed. Wiping means for cleaning, and wiping operation determination for determining whether or not to perform a wiping operation before printing scan based on the amount of ink per unit area applied to the recording material in the next printing scan area Means, the wiping operation within the printing page is performed at the time of low-duty printing scan in which image unevenness is unlikely to occur, thereby reducing image unevenness due to the wiping operation. An ink jet recording apparatus capable of preventing image deterioration is provided.

According to the second aspect of the present invention, in an ink jet recording apparatus for performing recording by discharging ink from a recording unit to a recording material, a wiping unit for cleaning an ejection port surface of the recording unit, and the recording unit Counting means for estimating the wetting state of the ejection port surface of the means, ink amount detecting means for detecting the amount of ink per unit area applied to the recording material in the next printing scan area, and the counting means Wiping operation determining means for determining whether or not to perform a wiping operation before printing scan based on the count value of the ink amount detection means and the detection value of the ink amount detecting means. By controlling the operation timing in accordance with the recording ratio, it is possible to reduce image unevenness that occurs when the wiping operation enters a recording page. Ink-jet recording that can reliably perform wiping before causing non-ejection due to wetting of the ejection port surface due to ink ejection, thereby maintaining good ink ejection reliability without reducing throughput and preventing image deterioration An apparatus is provided.

According to the third and fourth aspects of the invention, in addition to the configuration of the second aspect, the counting means is a dot counting means for counting the number of ink ejection dots.
Alternatively, since the counting means is configured to be a time counting means for counting a recording time, the timing of the wiping operation in the recording page is controlled according to the recording ratio, so that the wiping operation can be performed more efficiently. It can reduce the unevenness of the image that occurs when entering inside, and the wiping can be done before the non-ejection occurs due to the wetting of the ejection opening surface by the ink ejection, so the reliability of the ink ejection without reducing the throughput And an ink jet recording apparatus capable of preventing image deterioration by maintaining good image quality.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view showing a schematic configuration of an embodiment of an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is a partial perspective view schematically illustrating a structure of an ink ejection unit of a recording unit in FIG.

FIG. 3 is a block diagram illustrating a configuration of a control system of an embodiment of an inkjet recording apparatus to which the present invention has been applied.

FIG. 4 is an explanatory diagram illustrating locality of a recording ratio during one scan.

FIG. 5 is an explanatory diagram showing an example of a unit area for calculating a recording ratio in an ink jet recording apparatus to which the present invention has been applied.

FIG. 6 is a flowchart illustrating a control sequence of a wiping operation in the first embodiment of the ink jet recording apparatus to which the present invention is applied.

FIG. 7 is a flowchart illustrating a control sequence of a wiping operation in a second embodiment of the ink jet recording apparatus to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording means (recording head, head cartridge) 2 Carriage 3 Guide shaft 4 Main scanning motor (Carrier motor) 7 Timing belt 8 Recording material 9 Transport roller 11 Transport roller 14 Recovery system unit 15 Cap 16 Suction pump 17 Blade holder 18 Blade DESCRIPTION OF SYMBOLS 20 Conveying motor 21 Discharge port surface 22 Discharge port 24 Liquid path 25 Electrothermal converter 42 MPU 43 ROM 44 DRAM 45 Gate array 49 Various sensors

Claims (6)

[Claims] 1. An ink jet recording apparatus which performs recording by discharging ink from a recording unit to a recording material, wherein the wiping unit cleans an ejection opening surface of the recording unit, and the recording is performed in a next recording scanning area. An ink jet recording apparatus comprising: a wiping operation determining unit for determining whether to perform a wiping operation before printing scan based on an ink amount per unit area applied to a material. 2. An ink jet recording apparatus which performs recording by ejecting ink from a recording unit to a recording material, wherein the wiping unit cleans an ejection opening surface of the recording unit, and wets the ejection opening surface of the recording unit. Counting means for estimating the state of the ink, ink amount detecting means for detecting an ink amount per unit area applied to the recording material in the next printing scan area, count value of the counting means and the ink amount And a wiping operation determining means for determining whether or not to perform a wiping operation before printing scan based on a detection value of the detecting means. 3. An ink jet recording apparatus according to claim 2, wherein said counting means is a dot counting means for counting the number of ink ejection dots. 4. An ink jet recording apparatus according to claim 2, wherein said counting means is a time counting means for counting a recording time. 5. The ink jet recording means according to claim 1, wherein said recording means is an ink jet recording means having an electrothermal converter for generating thermal energy used for discharging ink. The inkjet recording apparatus according to any one of the preceding claims. 6. An ink jet recording apparatus according to claim 5, wherein said recording means discharges the ink from a discharge port using film boiling generated in the ink by thermal energy generated by the electrothermal transducer. .