JP2000108328A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet recorder in which a mode for attaining high quality recording by performing preheating or a mode for recording in a short time with lower record quality can be set selectively. SOLUTION: When the temperature of a recording head 3 is lower than a reference temperature and a switch 8 is set with a high quality recording mode, preheating is performed with a drive pulse of small pulse width causing no bubbling of ink. When the temperature of the recording head 3 reaches the reference temperature, recording is performed with a drive pulse of large pulse width for ink jet. Preheating requires a time but high quality recording can be carried out. When the temperature of the recording head 3 is lower than the reference temperature and the switch 8 is set with an immediate recording mode, preheating is not performed but recording operation is started immediately with the drive pulse of large pulse width for ink jet. Recording time is short because preheating is not performed although print quality is low. A user can select a mode depending on the use through switching operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a recording apparatus using an ink jet recording system.

[0002]

2. Description of the Related Art Conventionally, various recording apparatuses employing various recording methods have been developed. Among them, the ink jet recording method is capable of low-noise and high-speed recording because the recording medium is non-contact. In particular, the bubble jet method has various advantages such as high density recording is possible because of the high density arrangement of nozzles for ejecting ink, and color and size reduction are easy. Widely used.

In such an ink jet recording system, since ink droplets are ejected from the nozzles of the recording head for recording, the ejection state of the nozzles greatly affects the recording quality. The principle of discharging the ink droplets will be described with reference to FIG. As shown in FIG. 3A, when a voltage is instantaneously applied to a heater (heating element) 302 disposed in a nozzle 301 of the head of the ink jet recording apparatus, heat energy generated by the heater 302 causes the surrounding area to change. Is heated, a film boiling phenomenon occurs, and bubbles 304 are generated. When the bubble 304 grows, a part of the ink 303 is pushed away by the bubble 304 and jumps out from the tip of the nozzle 301 to the outside. Then, as shown in FIG. 3B, when the voltage application to the heater 302 stops, the bubble 30
The ink 4 is cooled by the surrounding ink and contracts, and the ink ejected from the nozzle tip is ejected as droplets 305 from the nozzle toward the recording medium S and adheres to the recording medium S to form an image.

[0004] Incidentally, the properties of the ink 303 used in such ink-jet recording, particularly the viscosity, greatly depend on the temperature, and the viscosity tends to increase as the temperature decreases. In order to perform recording, it is desirable that the ink droplets 305 fly perpendicular to the recording medium S. However, if the temperature is low and the viscosity of the ink is large, the ink droplets 305 do not have a uniform shape. As shown in (2), the ink droplet 305 may be small or fly in a different direction. Conversely, if the temperature of the head increases due to continuous printing for a long time and the viscosity of the ink decreases, the ejection amount increases, and a density difference occurs at the beginning of printing and after printing for a long time. These problems are particularly significant when using the printer in a low-temperature environment.

Conventionally, in order to eliminate such disadvantages,
Before starting recording, a preheating pulse (a driving pulse having a pulse width small enough to prevent bubbles) is supplied to the heater to perform preheating, and the head is heated so as to be within an appropriate temperature range. Has begun.

[0006]

However, although the above-described conventional method has the effect of improving the recording quality, it requires preheating before recording, so that the time until the start of recording (first print) is required. It takes. On the other hand, depending on the application of the user, not so high recording quality may be required for simple image recording such as simple characters, but even in such a case, conventionally, it is necessary to pre-heat the recording until the start of recording. Is taking a long time.

Therefore, an object of the present invention is to provide a mode in which sufficient preliminary heating is performed to obtain high-quality recording, and a mode in which printing can be performed quickly in a short time even if the recording quality is somewhat inferior, according to the use of the user. An object of the present invention is to provide an ink jet recording apparatus which can be selectively set.

[0008]

An ink jet recording apparatus according to the present invention comprises an ink jet recording head for discharging ink toward a recording medium, temperature detecting means for measuring the temperature of the ink jet recording head, and operation by a user. A changeover switch for switching between a high-quality printing mode and an immediate recording mode; and, when the temperature measured by the temperature detecting means is lower than a reference temperature, the ink-jet recording is performed when the changeover switch is set to a high-quality recording mode. Control means for starting the recording operation after the head is preheated and raised to a temperature equal to or higher than the reference temperature, and causing the inkjet recording head to immediately start the recording operation when the changeover switch is set to the immediate recording mode. Have.

The ink jet recording head discharges ink using energy generated by bubbling of the ink, and has a heating element for heating and bubbling the ink. The control means supplies a driving pulse having a large pulse width capable of heating and foaming the ink during the recording operation to the heating element, and supplies a driving pulse having a small pulse width at which the ink cannot foam during the preheating. Preferably.

According to such a configuration, a mode in which a user operates a changeover switch to obtain high-quality recording over time and a mode in which recording is performed in a short time regardless of the recording quality can be arbitrarily set. Can be selected.

[0011]

Next, an embodiment of the present invention will be described in detail.

FIG. 1 schematically shows the structure of an ink jet recording apparatus according to the present invention. This recording device is a card printer using card paper S as a recording medium,
As shown in FIG. 1, a feeding means 1 for supplying a card sheet S
Conveying means 2 for conveying the fed card paper S;
The printing apparatus includes a recording unit 3 that performs recording on a card sheet S that is a recording medium to be conveyed, and a discharging unit 4 that discharges the recorded sheet S.

The feeding means 1 has a tray 1a on which a sheet S as a recording medium is set. The tray 1a is provided with a side guide (not shown) that is slidable in the width direction of the tray 1a. The side guide can be slid to accommodate various sizes of paper from business cards to postcards. The tray 1a can set sheets S of different sizes, and can detect the width direction size of the set sheet S by a sensor 5 (see FIG. 2) attached to the side guide. The detection result of the sensor 5 is sent to the control means 6 (see FIG. 2), and under the control of the control means 6, recording according to the size of the sheet S is performed by the recording means 3 at the subsequent stage. For example, when the paper S is larger than the image to be recorded, recording is performed, and when the paper S is smaller, recording is controlled not to be performed, and ink is recorded in an area outside the paper (inside the recording apparatus). Is set so as not to be discharged.

The paper S set on the tray 1a is picked up by a pickup roller 1b, separated one by one by a separation pad 1e, and then sent between a feed roller 1d and a retard roller 1c. Is fed. Further, a shutter member 1f is provided downstream of the feed roller 1d. The shutter member 1f is opened and closed by a solenoid (not shown) every time one sheet of paper S is fed, and the skew of the sheet S is corrected by the leading end of the fed sheet S hitting the shutter member 1f.

The transporting means 2 comprises a synchro pulley / belt transporting unit capable of high-precision position control, and a transporting belt 2c extends over a driving pulley 2b and a driven pulley (not shown) over substantially the entire recording area. It is.
The transporting means 2 rotates the paper S sent from the feeding means 1 coaxially with a driven pulley (not shown) and a driving roller 2a which presses the paper S against the driving roller 2a. The sheet is transported by the pinch roller 2d, and further transported downstream by the transport belt 2c.

The recording means 3 of the present embodiment is an ink jet recording head for recording a color image by discharging ink onto the sheet S conveyed from the conveying means 2. As shown in FIG. 2, the inkjet recording head 3 of the present embodiment has a heating element (electrothermal conversion element) 3a as an energy generating unit. When a voltage is applied to the heating element 3a in response to the recording signal, the thermal energy generated by the heating element 3a causes the ink to boil and generate bubbles. The recording is performed by discharging toward S.

In the present embodiment, the black recording head 3b, the cyan recording head 3
c, magenta recording head 3m, yellow recording head 3y
Are arranged in order. It controls a rotation pulse signal of a stepping motor (not shown) of a driving unit 7 (see FIG. 2) for driving the driving pulley 2b, and controls ink ejection of the inkjet recording head 3 output from the control unit 6 (see FIG. 2). A digital signal (recording signal) is synchronized, and each ink jet recording head 3 responds to each recording signal by
A color image is recorded on the conveyed paper S by appropriately discharging ink of each color.

The sheet S on which an image has been recorded by the ink jet recording head 3 is discharged to a discharge stacker 4c by a discharge roller 4a and a spur 4b of a discharge means 4 and stacked.

Next, a method of controlling the operation of the recording head 3 of the ink jet recording apparatus will be described with reference to the block diagram of FIG.

In this embodiment, the heating means 3 of the ink jet recording head 3 is
a, a changeover switch 8 manually operated by a user, temperature detecting means 9 for measuring the temperature of the ink jet recording head 3, a sensor 5 for detecting the size of the sheet S in the width direction,
Each member for transporting the sheet S (the pickup roller 1
a, a feed roller 1d, a shutter member 1f, a driving pulley 2b, a discharge roller 4a, etc.).

When recording is performed in this ink jet recording apparatus, first, the control means 6 determines which ink jet recording head 3 should discharge ink at what timing according to an image to be formed. Then, the temperature detecting means 9 measures the temperature of the ink jet recording head 3 from which ink is to be ejected, and checks whether the temperature has reached a reference temperature required for normal ink ejection. If the temperature of the inkjet recording head 3 is equal to or higher than the reference temperature, the control unit 6 drives the inkjet recording head 3 and immediately starts the recording operation.

On the other hand, if the temperature of the ink jet recording head 3 detected by the temperature detecting means 9 is lower than the reference temperature, the viscosity of the ink may increase and the ejection characteristics may deteriorate. Here, the changeover switch 8 is set by a user to use a recording apparatus to obtain high-quality recording over time (high-quality recording mode) and to perform recording in a short time regardless of the recording quality (immediate recording mode). ) Is manually set to one of

When the temperature of the ink jet recording head 3 is lower than the reference temperature and the changeover switch 8 is set to the high-quality recording mode, the control means 6 controls the pulse width of the pulse width as small as not to cause the bubbling of the ink. By supplying a drive pulse to the heating element 3a of the inkjet recording head 3, the inkjet recording head 3 is preheated. When it is confirmed by the temperature detecting means 9 that the temperature of the ink jet recording head 3 has reached the reference temperature, the control means 6 sends a drive pulse having a large pulse width for normal ink ejection to the heating element 3 of the ink jet recording head 3.
a. When a drive pulse having a large pulse width for normal ink ejection is supplied to the heating element 3a, the ink is heated and foams, and the pressure causes ink droplets to be ejected from the inkjet recording head 3 and adhere to the paper S. Thus, recording is performed. In addition, a desired image is formed on the paper S by ejecting ink droplets from each inkjet recording head 3 at the same timing as the paper S is sequentially conveyed by the driving of the driving unit 7. Since the temperature of the ink jet recording head 3 is equal to or higher than the reference temperature, the viscosity is not too large, the normal ink ejection is performed, and high quality and uniform quality image recording is possible.

On the other hand, the ink jet recording head 3
Is lower than the reference temperature and the changeover switch 8 is set to the immediate recording mode,
However, a driving pulse having a large pulse width for normal ink discharge is immediately supplied to the heating element 3a without performing preheating, and the recording operation is started. In this case, since the viscosity of the ink is large, the ink ejection characteristics are poor and the print quality is poor. However, the time required for recording without the preliminary heating, particularly until the recording on the first sheet S is started. (The waiting time until the first print) can be shortened.

Since the present embodiment has such a configuration,
The user can operate the changeover switch 8 to select a mode and perform arbitrary image recording according to the application. For example, if the image quality is not important, such as when the content of the print is only text, or if quick recording is required, set the immediate recording mode. Such as setting to the quality recording mode,
Selection according to the application can be made at the discretion of the user. Therefore, efficient recording can be performed.

In the present embodiment, the minimum value of the temperature of the ink jet recording head 3 that can print well is set as a reference value, but the maximum value of the temperature of the recording head 3 that can print well can also be set. it can. That is, in this case, a reference temperature range suitable for recording is set. When the temperature of the inkjet recording head 3 is higher than the reference temperature range and the high-quality recording mode is set, image recording is not performed immediately, and the temperature of the inkjet recording head 3 decreases until the temperature falls within the reference temperature range. Is started by the temperature detecting means 9 before the recording operation is started. It is preferable that the inside of the recording apparatus is cooled by a fan or the like (not shown) until the temperature of the inkjet recording head 3 falls within the reference temperature range.

[0027]

According to the ink jet recording apparatus of the present invention, it is possible to select which of the high-quality recording and the shortening of the recording time is to be prioritized in the image recording in accordance with the user's own judgment according to the application, so that efficient recording can be performed. Can be done.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an ink jet recording apparatus of the present invention.

FIG. 2 is a block diagram for explaining recording operation control of the ink jet recording apparatus of the present invention.

FIG. 3 is an explanatory diagram illustrating the principle of an ink jet recording method.

FIG. 4 is an explanatory diagram showing a state of discharge characteristic deterioration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Feeding means 1a Tray 1b Pickup roller 1c Retard roller 1d Feed roller 1e Separation pad 1f Shutter member 2 Transport means 2a Drive roller 2b Drive pulley 2c Transport belt 2d Pinch roller 3 Recording means (inkjet recording head) 3a Heating element 3b Black recording Head 3c Cyan recording head 3m Magenta recording head 3y Yellow recording head 4 Discharging means 4a Discharging roller 4b Spur 4c Discharging stacker 5 Sensor 6 Control means 7 Driving means 8 Changeover switch 9 Temperature detecting means S Recording medium (card paper)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EB07 EB30 EC07 EC29 EC80 FA03 2C057 AG46 AL25 AM21 DA08 DB01 DD06 DE05

Claims (3)

[Claims] An ink jet recording head for discharging ink toward a recording medium; a temperature detecting means for measuring a temperature of the ink jet recording head; and a high quality printing mode and an immediate recording mode are switched by a user operation. A changeover switch, when the temperature measured by the temperature detecting means is lower than a reference temperature, and when the changeover switch is set to a high-quality recording mode, the inkjet recording head is preheated to rise to the reference temperature or higher. A control unit for starting a printing operation after heating, and causing the inkjet printing head to immediately start the printing operation when the changeover switch is set to an immediate printing mode. 2. The ink jet recording apparatus according to claim 1, wherein the ink jet recording head discharges the ink by using energy generated by foaming of the ink, and has a heating element for heating and foaming the ink. . 3. The control means supplies a drive pulse having a large pulse width capable of heating and foaming the ink during the recording operation to the heating element, and supplies a drive pulse having a small pulse width during which the ink cannot foam during the preheating. The ink jet recording apparatus according to claim 2, wherein the ink is supplied to the heating element.