JPH0714641B2 - Inkjet recording device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording apparatus, and more particularly to an inkjet recording apparatus capable of accurately detecting the remaining amount of ink.

[Prior Art] Conventionally, an inkjet recording apparatus records an image on a recording sheet or the like by ejecting ink droplets from minute nozzles, and a color image can be recorded by a simple image forming process. It has advantages and is rapidly becoming popular in recent years.

The ink remaining amount detecting means of the ink jet recording apparatus uses conductivity of ink, detects a change in vibration resistance of the ink tank due to presence or absence of ink with a piezoelectric element, and changes in light reflectance depending on presence or absence of ink. It is known to detect light with an optical sensor.

However, such an ink remaining amount detecting means requires a dedicated sensor. Therefore, in the case of forming a color image with three colors of yellow, magenta, and cyan, or four colors of ink with black added thereto,
Since a sensor is required for each color, the device becomes complicated,
There was a drawback that the cost was high.

Further, in an ink jet recording apparatus that forms an image while reciprocating the ink ejection nozzles, it is necessary to make the ink supply tube from the ink tank to the nozzles sufficiently long so that the nozzles can reciprocate sufficiently. There is a possibility that air will enter from the inside to generate air bubbles, resulting in a non-ejection state, or the tube may be damaged by the reciprocating movement of the nozzle. For this reason, a nozzle and an ink tank are placed on one carriage, and an image is formed while reciprocating the carriage. However, in such a device, the ink liquid in the ink tank is moved by the movement of the carriage. The surface vibrates, and the conventional method described above has a disadvantage that the remaining ink amount cannot be accurately detected.

As a means for eliminating the drawbacks of the above-mentioned conventional remaining amount detecting means and detecting the remaining amount without requiring a special sensor, the ejection signal supplied to the print head is counted, and the ink remaining amount is calculated based on the count value. It is known to detect quantity.

Normally, the amount of ink consumed by one dot is almost constant, so that it is possible to detect the remaining amount of ink with a simple configuration without using a special sensor.

[Problems to be Solved by the Invention] However, in a normal use environment and use condition, the remaining amount detection configuration described above can detect the remaining amount with sufficient accuracy. When the temperature around the head rises due to printing for a long time, an error may occur in the remaining amount detection due to the following reasons.

That is, the viscosity of the ink generally changes with temperature,
The higher the temperature, the lower the viscosity. On the other hand, the amount of ink ejected from the nozzle depends on the viscosity of the ink, and the lower the viscosity, the more the amount ejected. Therefore, the ink ejection amount increases as the temperature rises.

Therefore, when the temperature fluctuates drastically, the ink ejection amount may fluctuate, which may cause an error in the remaining ink amount detection.

[Means for Solving Problems] It is an object of the present invention to provide an ink jet recording apparatus that eliminates the drawbacks of the above-mentioned conventional example and can accurately detect the remaining ink amount regardless of temperature fluctuations. For that purpose, a print head that ejects ink in accordance with a supplied ejection signal, an ink tank that supplies ink to the print head, and a remaining amount of the ink tank based on the amount of ink ejected from the print head In an ink jet recording apparatus provided with a remaining amount detecting unit for detecting a state, a temperature detecting unit for detecting a temperature in the vicinity of the print head, and a predetermined unit based on an ink amount per ejection signal according to a temperature detected by the temperature detecting unit. And counting means for counting the ejection signals supplied to the print head, and the remaining amount detecting means is a count value of the counting means. The remaining amount state of the ink tank is detected based on the.

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

FIG. 1 is a block diagram of a recording apparatus provided with a conventional remaining amount detecting means.

1a to 1c are yellow (1a) and magenta (1) sent from an image reading unit or an image data recording device (not shown).
b), three-color (digital) image data signals of cyan (1c), which are input to the image processing unit 2. The image processing unit 2 performs undercolor removal, masking processing, gradation correction, and the like on these input signals. The image data signal subjected to the image processing is input to the dither processing unit 3 and compared with the threshold value stored in the dither ROM therein, and the result is output as binary image data 4a to 4c.

Binary image data 4a to 4c is output to the print head 5a as an ejection signal.
Supplied to ~ 5c. Heads 5a to 5c with discharge nozzles
Turns on the ejection nozzle according to the input image data.
Turn off.

As a method of ejecting ink, a method of heating the ink with a heater to generate bubbles and ejecting the ink by the energy thereof, a method of vibrating a nozzle with a piezoelectric element to eject the ink, and the like are used.

The image is formed in this manner, but the binary image data 4a to 4c as the ejection signal is supplied to the head and simultaneously input to the counters 6a to 6c. Predetermined values are preset in the counters 6a to 6c, and the ejection signals obtained from the binary image data are counted and warning signals 7a to 7c are output when the count value reaches the preset value. In response to the signals 7a to 7c, for example, a warning light (not shown) is turned on to indicate that there is no ink.

The preset value P of the counter is the ink amount consumed by one dot from the ejection nozzle, the ink tank capacity m,
Also, P = (m−n) / 1 is obtained according to the remaining ink amount n when displaying no ink.

As mentioned above, under the normal use environment and use conditions, the remaining amount can be accurately detected with the configuration of the conventional example, but when the environmental temperature fluctuates greatly or the temperature around the head rises due to printing for a long time. Etc., there is a possibility that an error may occur in the remaining amount detection due to a change in the ink ejection amount.

In consideration of the problems of the above-mentioned conventional example, the present invention enables more accurate detection of the remaining amount.

In the embodiment of the present invention, by providing the temperature detection element, by changing the preset value of the counter according to the temperature,
Eliminate the effects of temperature fluctuations.

FIG. 2 is a signal processing block diagram of an embodiment of the present invention, in which the same reference numerals as in FIG. 1 denote the same components.

In FIG. 2, a temperature sensor 8 such as a thermistor is further provided in the configuration shown in FIG. The temperature signal 9 from the temperature sensor 8 is input to the analog / digital converter 10, converted into a digital signal, and then input to the ROM 11 as address data.

The ROM 11 converts the digital temperature signal into a corresponding counter preset signal, and the counter preset signal corrects the preset values of the counters 12a to 12c.

FIG. 3 is a diagram showing the relationship between the temperature and the ink ejection amount. As described above, the ink ejection amount increases as the temperature rises. The ROM 11 has, for example, as shown in FIG.
Counters 12a to 12c when the discharge amounts at B and C are a, b and c
Convert the temperature signal into a preset signal so that the preset values of are in the ratio of 1 / a: 1 / b: 1 / c respectively.

This point will be specifically described. Temperature A shown in FIG.
In this case, the discharge amount a at X is X, and the delivery amount b at temperature B is 1.2X, which is larger than a. At this time, the preset value of the counter 12 is, for example, 6 at the temperature A and 5 at the temperature B. Therefore, since the counter 12 generates a pulse when the count value of the ejection signal reaches the preset value, the counter 12 generates a pulse for each ink ejection amount 6X at any of the temperatures A and B.

In this way, by the preset signal according to the temperature,
The counters 12a to 12c are preset, and a pulse is generated each time the binary image data 4a to 4c reaches the preset value. That is, the preset values of the counters 12a to 12c are corrected so as to generate the pulse corresponding to the predetermined discharge amount regardless of the temperature. The pulses generated by the counters 12a to 12c are counted by the counters 13a to 13c, and when a predetermined value is reached there, warning signals 7a to 7c are output and a warning lamp (not shown) is turned on to indicate that there is no ink.

With such a configuration, the pulses counted by the counters 13a to 13c correspond to a predetermined ink ejection amount regardless of the temperature, and the remaining ink amount can be detected extremely accurately.

In this embodiment, the temperature sensor 8 may be attached at any position where the ambient temperature of the image recording apparatus can be detected, but if it is at or near the head, the temperature is very close to the temperature of the ink to be ejected. Are more preferable because they can be detected.

In each of the above-described embodiments, the head using three colors of yellow, magenta, and cyan has been described, but the present description is not limited to this, and in the case of a single color, two colors, four
The same can be done in the case of color.

As described above, according to the present invention, the temperature is detected, the ejection signal is counted in a predetermined unit based on the ink ejection amount according to the temperature, and when the count reaches a predetermined value. ,
For example, with a simple configuration in which a signal indicating that there is no ink is generated, it is possible to detect the remaining ink amount extremely accurately regardless of fluctuations in the ink ejection amount due to temperature fluctuations.

[Brief description of drawings]

FIG. 1 is a block diagram of a recording apparatus having a conventional remaining amount detecting means, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a diagram showing a relationship between temperature and ink ejection amount. . Input image data 1a to 1c 2 Image processing unit 3 Dither processing unit 5a 5c Head 6a 6c 12a 12c 13a 13c Counter

Claims (2)

[Claims] 1. A print head which ejects ink in response to a supplied ejection signal, an ink tank which supplies ink to the print head, and a remaining amount of the ink tank based on the amount of ink ejected from the print head. In an ink jet recording apparatus provided with a remaining amount detecting unit for detecting an amount state, a temperature detecting unit for detecting a temperature near the print head, and a predetermined amount based on an ink amount per ejection signal according to a temperature detected by the temperature detecting unit. A unit for counting the number of ejection signals supplied to the print head, wherein the remaining amount detecting unit detects the remaining amount state of the ink tank based on the count value of the counting unit. Inkjet recording device. 2. The first counting means for counting the ejection signals supplied to the print head and generating a signal each time the count value reaches a preset value, and the temperature detecting means. Correction means for correcting the preset value of the first counting means based on the ink amount per ejection signal according to the detected temperature; and second counting means for counting the signals generated by the first counting means. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus comprises: