JP2014104675A - Ink jet recording device and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adequately detect the attitude of a recording device and to achieve downsizing of the recording device.SOLUTION: An ink jet recording device includes: a carriage on which recording heads for performing recording by discharging ink are mounted and which performs going scanning and returning scanning; ink tanks for storing ink; ink passages for supplying the ink from the ink tanks to the recording heads; and pressure detecting means which is disposed on the carriage and detects ink pressure. Each of ink pressures at two end parts in a range where the carriage performs scanning is detected and acquired by the pressure detecting means, each ink pressure is compared with a preset adequate pressure range, and when the ink pressure is not within the adequate pressure range, a warning of an error is issued.

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method, and more particularly to an ink jet recording apparatus and an ink jet recording method for detecting the attitude of an ink jet recording apparatus.

  When the recording device is used in a tilted position rather than horizontally, ink is ejected due to minute vibrations, and the ink adheres to the ejection surface and is transferred to the recording medium. There are things to do. This is because, for example, when the recording apparatus is tilted, a drop occurs at the left and right ends of the carriage scan width, and pressure is applied to the lower ends at the left and right ends.

  As a technique for detecting the posture such as the inclination of the recording apparatus, Patent Document 1 discloses a method of detecting the posture by installing pressure detection means in each of the main tank and the spare tank. According to this method, the apparatus attitude is detected from the comparison of the detection results of the pressure detection means, the pressure fluctuation (ink remaining amount and apparatus inclination) is absorbed by the negative pressure application means, and stable ink ejection is realized, High quality descriptions can be made.

JP 2003-300332 A

  However, in the configuration of the recording apparatus described in Patent Document 1, since a plurality of pressure detection means and negative pressure application means must be provided, the configuration of the recording apparatus becomes complicated, resulting in an increase in size of the apparatus. In particular, in the case of a portable mobile printer in which posture change is likely to be a problem, it is difficult to mount in terms of size.

  Further, in the tube supply type serial printer, the pressure fluctuation due to the inertia of the ink in the tube is large, and furthermore, the dynamic pressure fluctuation in the acceleration / deceleration range (usually about 100 msec) of the carriage, the ink can be detected only by detecting the apparatus posture. Discharge cannot be stabilized. Furthermore, when the negative pressure is applied by the pump, the response is insufficient and it is impossible to follow the dynamic pressure fluctuation.

  The present invention has been made in view of the above points, and provides an ink jet recording apparatus and an ink jet recording method capable of appropriately detecting the orientation of the recording apparatus and reducing the size of the recording apparatus. With the goal.

  Therefore, in the present invention, a recording head that performs recording by discharging ink is mounted, a carriage that performs forward scanning and backward scanning, an ink tank that stores ink, and an ink tank for supplying ink from the ink tank to the recording head. An ink jet recording apparatus comprising: an ink flow path; and a pressure detection unit that is provided in the carriage and detects the pressure of the ink, and each of the two ends of the range scanned by the carriage by the pressure detection unit The pressure of each ink is detected and acquired, the pressure of each ink is compared with a preset appropriate pressure range, and if the ink pressure is not within the proper pressure range, an error is warned. It is characterized by.

  According to the above configuration, it is determined whether or not the pressures at the two end portions of the carriage scanning range are within a range where accurate ejection can be performed even if the recording apparatus is inclined. As a result, it is possible to properly detect the attitude of the recording apparatus and to reduce the size of the recording apparatus.

1 is a top view illustrating a serial type ink jet recording apparatus according to a first embodiment. It is a side view which shows the inkjet recording device seen from the arrow 9 direction in FIG. It is a graph which shows the relationship between the carriage speed and pressure of 1st Embodiment. It is a graph which shows the relationship between the carriage speed and pressure of 1st Embodiment. It is a flowchart which shows the inclination detection operation | movement of 1st Embodiment. It is a flowchart which shows the inclination detection operation | movement of 2nd Embodiment.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a top view showing the serial type ink jet recording apparatus of the present embodiment. FIG. 2 is a side view showing the ink jet recording apparatus viewed from the direction of arrow 9 in FIG. The ink jet recording head 1 is composed of black, yellow, magenta, and cyan ink jet recording heads arranged in parallel. The ink jet recording head 1 has 600 nozzles at 1/600 inch pitch for each color. The ink jet recording head 1 is fixed to a carriage 2, and a guide shaft 8 passes through the carriage 2. The carriage 2 is supported by the guide rail and can scan in the forward scanning direction and the backward scanning direction (10 directions shown in FIG. 1).

  The ink jet recording head 1 is supplied with an electrical signal from a main substrate via a flat cable, and ejects ink from an ejection port. Ink tubes 4 (ink flow paths) are connected to the heads 1 of the respective colors, and are connected to four main tanks 3 that respectively store the inks of the respective colors. That is, ink is supplied from the four main tanks 3 to the recording heads 1 of the respective colors through the ink tubes 4 (ink flow paths). An air communication port 11 is provided inside the main tank 3. Air is introduced into the atmosphere communication port 11 as the ink is consumed. The air communication port 11 is provided with a check valve (not shown) so that ink does not leak even when the ink tank is tilted.

  The water level of the tank varies from 10 mm to 70 mm from the bottom, and at this time, the water head difference (h) 12 between the water surface in the tank and the ejection surface of the ink jet recording head is −130 mm to −70 mm. When the carriage 2 is scanned in 10 directions, the ink tube 4 has a shape as indicated by a two-dot chain line 5 at the right end.

  The pressure sensor 7 is a sensor that measures the ink pressure in the tube, and measures the gauge pressure based on the atmospheric pressure. The pressure sensor 7 is provided immediately before the tube 4 connection to the black head. As the pressure sensor, a piezoresistive semiconductor pressure sensor that detects pressure by changing a thin film semiconductor strain resistance formed on a resin diaphragm is mounted.

With the above configuration, the apparatus tilt in the main scanning direction can be detected by scanning the carriage 2 in the main scanning direction, changing the position, and measuring the pressure. In addition, the carriage performs acceleration / deceleration driving, and at this time, the pressure fluctuation represented by the following equation occurs due to the ink inertia in the tube.
Pressure fluctuation P (kPa) = ρaS / 1000 due to ink inertia (1)
ρ: ink density (kg / m ³ )
a: Carriage acceleration (m / s ² )
S: Horizontal distance between tank and head (m)

  The density ρ varies depending on the environmental conditions, the carriage acceleration a varies depending on the recording mode, and the horizontal distance S between the tank and the head varies depending on the reversal position during scanning, so P is not constant.

  In this embodiment, when the carriage is reversed at the right end, a positive pressure fluctuation occurs, and a pressure is generated so that the ink is ejected from the head ejection port. Conversely, negative pressure fluctuations occur at the left end, and a pressure is generated that causes the meniscus surface of the head nozzle to retreat.

  FIG. 3 is a graph showing the relationship between carriage speed and pressure in this embodiment. The horizontal axis represents time (msec), the vertical axis represents speed for the carriage speed graph (solid line), and the pressure for the ink inertia pressure graph (broken line).

  Although pressure fluctuation is observed during the period in which the acceleration is applied to the carriage, the pressure shows a reaction delayed by about 20 msec with respect to the acceleration. The pressure fluctuation range is about 0.9 kPa.

  FIG. 4 is a graph showing the relationship between carriage speed and pressure when the recording apparatus of this embodiment is tilted. When the recording apparatus is placed on a non-horizontal ground surface, for example, if the apparatus angle is 5 ° with respect to the horizontal, a drop of about 25 mm occurs at the left and right ends of the carriage scan width. When the left side of the recording apparatus shown in FIG. 1 is placed high, when the carriage is positioned at the right end, a head difference of 25 mm is displayed in a Pascal manner and added by 0.25 kPa. FIG. 4 shows the fluctuation of the total pressure in such a state. The horizontal axis represents time (msec), the vertical axis represents speed for the carriage speed graph, and pressure for the ink inertia pressure graph.

  As shown in the figure, when the carriage is located at the right end, the total pressure exceeds 0 kPa as shown at the vertex A in FIG. On the other hand, an appropriate pressure range in which optimum discharge can be performed is set in advance for the recording head, and the range is −2.5 to 0 kPa. When the pressure exceeds 0 kPa, the ink may be ejected due to minute vibrations, and the ink may adhere to the ejection surface and be transferred to the recording medium, or the ink droplet may be pulled by the adhered ink and fly obliquely.

  Further, when the left side of the recording apparatus is placed high, it becomes 0.05 kPa as indicated by a point A shown in FIG.

When the right side of the recording apparatus is placed high, the carriage is pulled by 0.25 kPa when the carriage is positioned at the right end. Therefore, if the main tank is almost empty,
−1.3 + 0.5−0.25 = −1.05
It becomes. This is subtracted by a pressure loss of 0.6 at the maximum ink flow rate.
-1.05-0.6 = -1.65
In this case, it is within the allowable range.

  However, 1.3 is a value indicating 130 mm in the range of −130 mm to −70 mm of the head differential (h) of the ejection surface of the recording head, and 0.5 is a pressure fluctuation range of about 0.9 kPa. Is half of the value rounded to the nearest 0.1.

However, unlike this embodiment, when the main tank is installed near the right end, when the left side is placed high, -1.3-0.5-0.25-0.6 =- 2.65
Thus, it is out of the allowable range. At this time, the negative pressure becomes too large compared to the pressure at which the ink is to be ejected, resulting in incomplete ejection, and the ink droplet volume does not reach an appropriate level, or the ink droplet speed drops and the landing position on the recording medium is large. Defects such as deviation occur. Even if the pressure does not exceed the allowable range as described above, density unevenness on the left and right may be a problem when a photograph is recorded on a special paper dedicated to photography. In this case, since the water level of the main tank is considered to be substantially the same on the left and right in one row, the level of the left / right difference corresponding to the ink inertia and the device inclination becomes a problem.

  In this embodiment, recording in the acceleration / deceleration area is not performed in the photo recording mode. In the plain paper mode, priority is given to shortening the recording time, and in order to shorten the scan width, ejection is performed in the acceleration / deceleration region. In the photo recording mode, the scan width is increased and acceleration / deceleration is performed outside the recording width. However, as shown in FIG. 3, since the response of pressure fluctuation is delayed with respect to acceleration / deceleration, some pressure fluctuation remains even at the start of recording. The left-right difference level of the pressure obtained by adding the device inclination to this and the concentration difference are in a proportional relationship. Therefore, the quality of a photographic image can be improved by suppressing the pressure difference within an allowable range.

  In this embodiment, when the pressure difference at the left and right ends of the constant speed region exceeds 0.7 kPa, it is determined that the density unevenness is out of the allowable range, and a device tilt warning is displayed to the user to prompt improvement. In this embodiment, when a device tilt warning is issued, a pressure detection instruction button (not shown) appears on the printer driver screen, and prompts the pressure to be measured again after the tilt is improved.

  While scanning the carriage, recording is performed while intermittently feeding the recording medium by a recording medium conveying means (not shown), and the recording is completed by discharging the sheet.

  Next, the tilt detection operation will be described.

  FIG. 5 is a flowchart showing the tilt detection operation of the present embodiment. When the recording signal is input (step S1), the carriage is scanned with the maximum scanning width without ejecting ink from the recording head (step S2). At this time, scanning is performed at a speed and acceleration corresponding to the recording mode designated by the user before inputting the recording signal. Then, the ink pressures A and B at the right end (home side) and the left end (away side) and the pressures a and b at the right end and the left end of the constant speed region are measured using the pressure sensor 7 (step S3). It is determined by comparing whether or not A and B are in the range of −2.5 KPa ≦ A and B ≦ 0 kPa, which are predetermined pressure standards (step S4).

  If the pressure is within the predetermined pressure reference, it is determined that the ink ejection is not stable due to the inclination of the apparatus, and an apparatus inclination warning is issued (step S8). Thereafter, the user takes measures to improve the device inclination (step S9). When the pressure detection instruction button is pressed (step S10), the process returns to step S2 and the pressure measurement process is performed again.

  If it is determined that the ink ejection is stable, then whether or not the recording medium on which the recording is performed is a recording medium designated in advance (in this embodiment, photo-dedicated paper such as glossy paper). Is determined (step S5). If it is not a photo-dedicated sheet, the apparatus skew is within the allowable range (step S7), the skew detection operation is terminated, and the recording operation is continued.

  On the other hand, in the case of photo-dedicated paper, it must be separately determined whether or not there is a problem such as uneven density in the photo-dedicated paper. In this case, the difference between the pressure a on the constant speed region home side and the pressure b on the away side is determined by comparing whether or not the relationship | a−b | ≦ 0.7 (kPa) is satisfied (step S6). ). If this relationship is satisfied, the apparatus inclination is determined to be within the appropriate range (step S7), the skew detection operation is terminated, and the recording operation is continued. On the other hand, if the relationship | a−b | ≦ 0.7 (kPa) is not satisfied, the process proceeds to step S8.

  Here, 0.7 kPa, which is an appropriate pressure range, is a value calculated based on whether or not density unevenness due to a density difference can be visually recognized through an experiment, and is preset in the storage memory.

  In this embodiment, a piezoresistive semiconductor pressure sensor is mounted as the pressure sensor. However, in the present invention, the pressure detection means is not limited to this. For example, a film with a movable electrode called a diaphragm bends as the pressure changes, and the capacitance between the fixed electrode and the fixed electrode changes, and the amount of change is converted into an electrical signal. A capacity method or the like may be used.

  Further, when the recording medium is a photographic paper, it was determined whether or not the pressure difference at the left and right ends of the constant speed region was | a−b | ≦ 0.7 (kPa). However, in the present invention, when acceleration / deceleration recording is performed even in the case of photographic recording, it may be determined whether or not the difference between the left and right pressures in the acceleration / deceleration region is within a predetermined range. Further, it may be determined whether the pressure value and the difference in pressure value are within an appropriate range, not only by the recording medium type, but also by the image quality mode (fast, standard, clean, etc.).

  The appropriate range itself also varies depending on the type of recording medium and image quality, so for example, the normal paper is in the fast mode, the allowable range is widened, and the glossy paper clean mode is narrowed to optimize the image. It is also effective to measure.

  In this embodiment, after the recording signal is input, the pressure is measured by performing a scan without ejecting ink from the recording head. However, the present invention scans when the power switch is turned on during paper discharge. Then, a method of measuring pressure may be used. Although the most reliable method is performed immediately before recording as in the present embodiment, the optimum recording state can be maintained in most cases even at such timing.

(Second Embodiment)
In the first embodiment, the density ρ, acceleration a, and horizontal distance S, which are influential factors on pressure fluctuation due to ink inertia, are measured immediately before recording.

  However, depending on the ink, the change in density due to environmental conditions may be minute, and the acceleration may be constant regardless of the mode. Regarding the horizontal distance, the maximum and minimum values are known. In such a case, the pressure fluctuation due to inertia can be treated as a fixed value.

  Therefore, when the carriage is stopped, the sum of the ink remaining in the tank and the device tilt are acquired at multiple positions in the scan range, especially at the left and right ends, and the fixed values for inertia are further summed to determine whether they are within the allowable range. By doing so, substantially the same effect as in the first embodiment can be obtained.

(Third embodiment)
In the first embodiment, when the pressure on the home side / away side or the pressure difference between the left and right ends of the constant speed region is not between predetermined values, a device tilt warning is issued to improve the device tilt. However, according to the present invention, even when the above-described pressure is not between the predetermined values, the acceleration of scanning the carriage is decelerated so as to reduce the inertial force. Image quality can be recorded.

  FIG. 6 is a flowchart showing the tilt detection operation of the present embodiment. Steps S1 to S3 and steps S5 and S7 are the same as those in the first embodiment, and thus description thereof is omitted.

If it is determined in step S4 or step S6 that the pressure is outside the allowable range, it is determined whether or not the acceleration is decreased for the first time (step S20). If the acceleration is decreased for the first time, the default value of the acceleration / deceleration of carriage movement is 11 m / s ² and is reduced to 7.3 m / s ² and 2/3. Thereafter, the carriage is scanned and the pressure is measured again in the same manner (steps S2 and S3).

  On the other hand, if the acceleration is decreased for the second time, it is determined that an abnormality that cannot be dealt with even if the acceleration is decreased is determined as an error (step S22).

  In the present embodiment, the acceleration may be decreased stepwise and the measurement may be repeated until the pressure falls within an allowable range.

1 Recording head 2 Carriage 3 Main tank 7 Pressure sensor

Claims (5)

A carriage that performs recording by ejecting ink, a carriage that performs forward scanning and backward scanning, and
An ink tank for containing ink;
An ink flow path for supplying ink from the ink tank to the recording head;
Pressure detecting means provided on the carriage for detecting the pressure of the ink;
An inkjet recording apparatus comprising:
The pressure detection means detects and acquires the pressure of each ink at two ends of the range scanned by the carriage, compares the pressure of each ink with a preset appropriate pressure range, An ink jet recording apparatus that warns of an error when the pressure of the ink is not within an appropriate pressure range.   When the pressure of each of the inks is compared with a preset appropriate pressure range, and recording is performed on a predetermined recording medium even when the ink pressure is within the proper pressure range The pressure detection means detects and acquires the pressure of the ink in the constant speed region of the carriage in the forward scan and the backward scan, respectively, and presets the value of the difference in the pressure of the ink in the constant speed region of the carriage. The inkjet recording apparatus according to claim 1, wherein an error is warned when the difference in ink pressure is not within the proper pressure range.   3. The ink jet recording apparatus according to claim 1, wherein when the error is warned, the acceleration of the carriage is delayed and the pressure is detected by the pressure detecting means.   The inkjet recording apparatus according to claim 3, wherein the acceleration of the carriage is slowed once. A recording head that performs recording by discharging ink; a carriage that performs forward scanning and backward scanning; an ink tank that stores ink; an ink flow path for supplying ink from the ink tank to the recording head; An ink jet recording method for performing recording by an ink jet recording apparatus provided with a pressure detection means for detecting the pressure of ink provided on a carriage,
The pressure detection means detects and acquires the pressure of each ink at two ends of the range scanned by the carriage, compares the pressure of each ink with a preset appropriate pressure range, An ink jet recording method characterized by warning an error when the pressure of the ink is not within an appropriate pressure range.

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