JP2002361856A - Apparatus and method for recording image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet image recorder and an image recording method by which stable printing characteristics can be obtained at all times against a temperature change based on an ambient temperature change as well as a temperature change of the image recorder. SOLUTION: A temperature sensor 55 is set to the vicinity of a recording head 14 in the image recorder having an ink jet recording head 14 comprising a plurality of recording elements. A multi-valued image data 50 inputted to the image recorder is inputted to a processing means 51 with a γ correction ROM and is table converted on the basis of a γ correction table (table showing a relation when an input image signal is converted to a printing signal). A binary image data 53 through a halftone processing means 52 is inputted to a recording head drive circuit means 54 to make the recording head 14 discharge ink drops. The processing means 51 having the γ correction ROM changes the γ correction table in accordance with a temperature signal 56 to prevent ink from being supplied too much or too little according to the environmental temperature change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image recording apparatus and an image recording method, and more particularly to an ink jet type image recording apparatus and an image recording method for performing recording by discharging ink onto a recording material.

[0002]

2. Description of the Related Art Recording is performed by discharging ink onto a recording material.
The so-called inkjet head has many advantages such as extremely low noise at the time of recording, high-speed printing, and the use of inexpensive plain paper with a high degree of freedom of ink. It is used as an output machine. Among them, the so-called ink-on-demand method, in which ink droplets are ejected only when printing is necessary, is currently the mainstream because it is not necessary to collect ink droplets unnecessary for printing. In the ink-on-demand method, there are a method using a piezoelectric element, a method using a heating element, a method using electrostatic force, and the like as means for generating ejection energy (pressure).

In general, inks that are liquid at room temperature or inks that solidify at or below room temperature and soften at room temperature are used. This also changes the viscosity of the ink. When the recording element is always driven under the same conditions to perform ink ejection, a difference in the ejection characteristics of ink droplets ejected from the nozzle occurs due to a change in ink viscosity. Specifically, as the temperature increases, the viscosity of the ink decreases, the ejection amount Mj of the ink droplet increases, and the flying speed Vj of the ink droplet tends to increase. Conversely, when the temperature decreases, the viscosity tends to increase, Mj decreases, and Vj tends to decrease.

[0004] In order to always perform stable printing on a recording material, a change in the ejection characteristics of ink droplets due to a temperature change becomes a serious problem. Techniques for correcting the ink droplet ejection characteristics with respect to the temperature change and for compensating for the temperature have been studied in the past. In order to avoid the influence of the ink becoming unstable, it is mentioned that an ejection amount control means for controlling the ink ejection amount is provided.

[0005]

However, in the case of the conventional example, a measure is taken against the problem of temperature rise due to the provision of a heating and drying means by a heating element in the apparatus itself. In addition, it is not preferable in terms of cost to provide a heating element for drying. Therefore, an object of the present invention is to provide an ink jet image recording method and an ink jet image recording apparatus capable of always obtaining stable printing characteristics even with respect to a temperature change taking into account the ambient environment temperature change.

[0006]

According to an aspect of the present invention, there is provided an image recording apparatus for recording an image by a recording head having a plurality of recording elements having nozzles for discharging ink. Temperature detecting means for detecting a temperature relating to the recording head, and drive control means for controlling an amount of ink ejected from each recording element of the recording head according to the temperature detected by the temperature detecting means; The drive control means selects an appropriate γ table from a plurality of γ tables provided in advance in accordance with the detected temperature and changes the input image signal.

According to a second aspect of the present invention, there is provided the image recording apparatus according to the first aspect of the present invention, further comprising one or a plurality of recording heads, and the recording heads are provided with different colors for a plurality of recording elements constituting the recording head. Recording element group that ejects ink of
Or a plurality of recording heads each ejecting ink of a different color, and a plurality of γ tables corresponding to each ink color are provided for each of the recording element groups ejecting each color ink or for each recording head. And

According to a third aspect of the present invention, there is provided an image recording apparatus for recording an image by a recording head having a plurality of recording elements having nozzles for ejecting ink, wherein the image recording apparatus has a dot diameter to be printed. A plurality of different printing modes, a temperature detecting unit for detecting a temperature relating to the recording head, and discharging from each recording element of the recording head for each printing mode in accordance with the temperature detected by the temperature detecting unit. And a drive control unit for controlling the amount of ink to be supplied.

According to a fourth aspect of the present invention, in the image recording apparatus according to the third aspect of the present invention, the drive control means selects one of a plurality of γ tables provided in advance for each print mode.
An appropriate γ table is selected according to the temperature detected by the temperature detecting means, and an input image signal is changed.

According to a fifth aspect of the present invention, there is provided an image recording apparatus.
In the image recording apparatus according to the invention, the recording element includes a nozzle, an ink liquid chamber, and a pressure generating unit, and the recording head is an inkjet recording head that discharges ink by the pressure generating unit.

According to a sixth aspect of the present invention, there is provided an image recording method in which an image is recorded by a recording head having a plurality of recording elements having nozzles for discharging ink, a temperature detecting step of detecting a temperature related to the recording head. A driving control step of controlling an amount of ink ejected from each recording element of the recording head in accordance with the temperature detected by the temperature detecting step; Therefore, an appropriate γ table is selected according to the detected temperature, and the input image signal is changed.

[0012]

FIG. 1 is a block diagram showing an embodiment of the present invention.
A description will be given based on the embodiment shown in FIGS. Here first,
As an example of an image output device using an ink jet recording head, a main body configuration of the ink jet recording device will be described. FIG. 1 is a perspective view for explaining a main part of the ink jet recording apparatus, and FIG. 2 is a side sectional view of the same. This ink jet recording apparatus includes a recording head 1 including a carriage 13 movable in the main scanning direction inside a recording apparatus main body 1 and an ink jet head mounted on the carriage 13.
4. A paper feed cassette which houses a printing mechanism unit 2 including an ink cartridge 15 for supplying ink to the recording head 14 and the like, and in which a large number of sheets 3 can be loaded from the front side under the recording apparatus main body 1. (Or paper feed tray) 4 can be inserted and removed freely, and a manual feed tray 5 for manually feeding paper 3 can be opened. The sheet 3 to be fed is taken in, a required image is recorded by the printing mechanism unit 2, and then the sheet is discharged to a sheet discharge tray 6 mounted on the rear side.

The printing mechanism 2 slides the carriage 13 in the main scanning direction (the direction perpendicular to the plane of FIG. 2) by a main guide rod 11 and a sub guide rod 12 which are guide members which are laterally mounted on left and right side plates (not shown). The recording head 14 is composed of an ink jet head for ejecting ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk). They are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward. Also, the carriage 1
In FIG. 3, each ink cartridge 15 for supplying each color ink to the ink jet head is exchangeably mounted.

The ink cartridge 15 has an upper air port communicating with the atmosphere, a lower supply port for supplying ink to the ink jet head, and a porous body filled with ink inside. The ink supplied to the inkjet head by the capillary force is maintained at a slight negative pressure.

Although a recording head for each color is used here as the recording head 14, a single head having a nozzle group for ejecting ink droplets of each color may be used. Further, the ink jet head used as the recording head 14 is a piezo type in which the ink is pressurized through a vibrating plate forming a liquid chamber wall by an electromechanical transducer such as a piezoelectric element, or a bubble is generated by a heating resistor to generate the ink. A bubble type that pressurizes or an electrostatic type that presses ink by displacing the vibrating plate with electrostatic force between a vibrating plate forming an ink flow path wall surface and an electrode facing the vibrating plate can be used.

The carriage 13 is slidably fitted on the rear side (downstream side in the paper transport direction) to the main guide rod 11, and slides forward (upstream side in the paper transport direction) on the slave guide rod 12. It is freely placed. In order to move and scan the carriage 13 in the main scanning direction, a driving pulley 18 and a driven pulley 19 that are rotationally driven by a main scanning motor 17 are provided.
And the timing belt 20 is fixed to the carriage 13, and the carriage 13 is reciprocated by the forward and reverse rotation of the main scanning motor 17.

On the other hand, the paper 3 set in the paper feed cassette 4
In order to transport the paper 3 to the lower side of the head, a paper feed roller 21 and a friction pad 22 that separate and feed the paper 3 from the paper feed cassette 4, a guide member 23 that guides the paper, and a reverse of the fed paper 3 Transport roller 24 for transport
And a transport roller 25 pressed against the peripheral surface of the transport roller 24 and a tip roller 26 for defining an angle at which the paper is fed from the transport roller 24. Transport roller 24
Is rotationally driven by a sub-scanning motor 29 via a gear train.

An image receiving member 27 is provided as a paper guide member for guiding the paper 3 sent from the transport roller 24 below the recording head in accordance with the moving range of the carriage 13 in the main scanning direction. . This print receiving member 2
At the downstream side in the paper transport direction of 7, there are provided a transport roller 31 and a spur 32, which are driven to rotate to transport the paper 3 in the paper discharge direction,
3 and spur 34, and guide member 3 forming a paper discharge path
5, 36 are arranged.

At the time of recording, the recording head 14 is driven in accordance with an image signal while moving the carriage 13 to discharge ink on the stopped paper 3 to record one line and convey a predetermined amount of paper. Later, the next line is recorded. Upon receiving a recording end signal or a signal indicating that the rear end of the sheet has reached the recording area, the recording operation is terminated and the sheet 3 is discharged.

At a position outside the recording area on the right end side of the carriage 13 in the moving direction, a recovery device 37 for recovering head ejection failure is disposed. The recovery device 37 has cap means, suction means and cleaning means. While the carriage 13 is waiting for printing, the recovery device 37
Then, the head is capped by the capping means and the ejection port is kept wet, thereby preventing ejection failure due to ink drying. In addition, by discharging ink that is not related to printing during printing or the like, the ink viscosity of all the outlets is kept constant, and stable discharging performance is maintained. In the event of a discharge failure, for example, the discharge port of the head is sealed with a capping means, bubbles are sucked out of the discharge port with ink by a suction means through a tube, and ink or dust attached to the discharge port surface is cleaned by a cleaning means. It is removed and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) provided at a lower portion of the main body, and is absorbed and held by an ink absorber inside the waste ink reservoir.

(First Embodiment) FIG. 3 is a block diagram showing drive control means according to a first embodiment of the present invention. The multi-valued image data 50 input from the left side shown in FIG.
The data is input to the processing means 51 having M and converted into a table. The γ table is understood in a broad sense and means a table representing a relationship when an input image signal is converted into a print signal. The table-converted data is input to the halftone processing unit 52 and converted into binarized image data 53, and the drive waveform is transferred to the printhead 1 via a printhead drive circuit 54.
4 to eject ink droplets.

FIG. 4 shows the γ stored in the γ correction ROM.
It is a figure for explaining a table. A plurality of γ tables are stored in the γ correction ROM, and when no conversion is required from the initial setting conditions, a γ table as shown in FIG. 4A is selected. Next, in the situation where the temperature rises, the drop ejection amount increases as the viscosity of the ink decreases, and as a result, the printed dots become larger and the image starts to be adversely affected. Specifically, as the spread of dots increases, the line becomes thicker, and in a print pattern in which a large amount of ink is ejected, the sharpness of the contour is poor and an image is blurred. In order to prevent such a problem, in the present embodiment, a temperature sensor 55 is provided near the recording head 14, the temperature is detected, and the γ correction table is changed as necessary as the temperature signal 56. 4 (b) to 4 (c) and 4 (d) as the temperature increases.
By changing the table in this order and changing the signal input to the binarization processing, it is possible to prevent excessive ink ejection and control the amount of ink.

(Second Embodiment) Next, a description will be given of a case where there are a plurality of ink colors based on a second embodiment. The ink jet recording head has an advantage that colorization can be easily performed when a plurality of heads having different ink colors are arranged in a device. The color output uses three colors of magenta, yellow, and cyan for monochrome output black. Further, when light magenta, light cyan or the like ink is used, more excellent image quality can be obtained when outputting a photographic image or the like. Here, an embodiment in the case of using the black and three color inks will be described. Some differences occur in the physical property values of the inks due to differences in the color materials used depending on the color. This difference also appears in the viscosity characteristics of the ink when the temperature changes, and is evident from the fact that when the same head is used to discharge ink droplets, the droplet discharge characteristics shift. By providing the drive control means shown in FIG. 3 for each color recording head as a means for appropriately correcting this shift, each ink can always obtain appropriate printing characteristics even when there is a temperature change. Here, the operation of the drive control means shown in FIG. 3 is the same as that of the first embodiment, and therefore will not be described. Also,
As a form having a plurality of ink colors, in addition to the case where the ink colors are different for each print head as described above, when a configuration is adopted in which a plurality of ink colors are provided in one print head, By employing the present invention for each recording element group that ejects ink, the same effects as in the present embodiment can be obtained.

(Third Embodiment) Next, as a third embodiment,
A case where the present invention is adopted as an ink jet printer will be described. FIG. 5 is a block diagram showing the configuration of the control unit of the printer main body according to the third embodiment. The control unit includes a CPU 60 that controls the entire recording apparatus, a ROM 61 that stores necessary fixed information, a RAM 62 that is used as a working memory, and the like, and converts print data (image information) received from a host into necessary color data. A color processing circuit 63 for performing processing such as decomposition, an image memory 64 for storing data obtained by processing image information, and a parallel input / output (PIO)
The port 65, the input buffer 66, and the gate array (G
A) or a parallel input / output (PIO) port 67, a head drive circuit 68, a driver 69, and the like.

Here, the print data (image information) received from the host 70 is stored in the input buffer 66, and the multi-valued color image data as the received data is converted into the color processing circuit 63.
And performs necessary processing such as gamma correction, UCR processing, and halftone processing, generates binary color image data, stores it as print data in the image memory 64, and prints in one scan. The data is read out and applied to the head drive circuit 68 via the PIO port 67 to drive the recording head 14 of the color corresponding to the recording head 14.

The PIO port 65 includes, in addition to image information from the host 70, data such as paper type data indicating the type of paper, various instruction information from the operation panel 71, and paper for detecting the start and end of the paper. A detection signal from the presence / absence sensor, signals from various sensors such as a home position sensor for detecting the home position (reference position) of the carriage 13 are input, and the host 70 side and the operation panel 71 side via the PIO port 65. The required information is sent to.

The head driving circuit 68 is a driving nozzle corresponding to the image information among the energy generating elements corresponding to each nozzle of the recording head 14 based on various data and signals given through the PIO port 67. A drive waveform is applied to the energy generating element of (1). Note that a shape such as a rectangular pulse, a triangular waveform, or a sine waveform can be used as the driving waveform.

Further, the driver 69 includes the PIO port 6
The carriage 13 is moved and scanned in the main scanning direction by controlling the driving of the main scanning motor 17 and the sub-scanning motor 29 in accordance with the driving data given via the control unit 7. Is transported in the sub-scanning direction by a predetermined amount.

In this embodiment, the print mode can be selected from the host or from the operation panel, and the size of the dot diameter to be printed is changed according to the mode selection. Specifically, the driving waveform can be switched so that the dot diameter is large in the draft mode in which the output speed is prioritized and small in the high image quality mode in which the image quality is prioritized. When the peak value is changed, a method of changing the waveform application time or the number of applied waveforms is effective for switching the drive waveform. In order to obtain large and small dot diameters, it is necessary to respond by changing the ejection amount of ink droplets.In such a case, ink droplets corresponding to large dot diameters are ejected and ink droplets corresponding to small dot diameters are When a droplet amount is discharged, a difference occurs in the discharge characteristics of the ink droplet due to a temperature change. As means for performing appropriate temperature correction corresponding to each condition with respect to this difference, FIG.
By providing the γ table corresponding to each print mode with the drive control means shown in (1), appropriate print characteristics suitable for each mode can be obtained even when there is a temperature change. Here, the operation of FIG. 3 is the same as that of the first and second embodiments, and thus the description thereof is omitted.

As the pressure generating means of the recording head used at this time, a method in which a piezoelectric element is provided outside the ink liquid chamber or a method in which an electrostatic force is used as an energy generating means is desirable. In the case where is used, since an operation faithful to a drive waveform such as an applied voltage can be obtained, it is easy to control the ejection characteristics of ink droplets by using switching of the drive waveform. On the other hand, the electrostatic method is an advantageous method in terms of power saving. In either case, since the pressure generating means does not directly touch the ink, it can be said that the ink selectivity is excellent.

Further, the image recording method using the drive control step of the present invention can be applied to an image output apparatus such as a facsimile apparatus and a copying machine by combining with a control section of various image output apparatuses.

[0032]

As is apparent from the above description, the present invention has the following effects. Since the temperature related to the recording head is detected, and the amount of ink ejected from each recording element of the recording head is changed according to the detected temperature by selecting an appropriate γ table by the drive control means and changing the input image signal. It has become possible to provide an inkjet image recording apparatus and an inkjet image recording method that can always perform stable printing even when there is a change in environmental temperature.

Further, by controlling the amount of ink even when the environmental temperature is high, it is possible to prevent the ink from being excessively ejected, to prevent the line from becoming wide due to the spread of dots, and to prevent the image from being blurred. Regardless, a stable printed image can be obtained.

Further, it is possible to cope with different ink colors, and even if there is a change in the environmental temperature, variations in the printed image due to the ink colors are suppressed, and a higher quality color image can be obtained.

Further, even in a printer having a print mode in which large and small dots are separated, appropriate temperature correction can be performed for each mode, and image disturbance due to a temperature change can be prevented. It has become possible.

Further, the present invention can be applied to various image output devices as an image recording method, and can be expected as an excellent temperature correction method.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a main configuration of an ink jet recording apparatus.

FIG. 2 is a side sectional view for explaining a main configuration of the ink jet recording apparatus.

FIG. 3 is a block diagram illustrating a configuration of a drive control unit according to the first embodiment.

FIG. 4 is a diagram for explaining a γ table stored in a γ correction ROM.

FIG. 5 is a block diagram illustrating a configuration of a control unit according to a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording device main body, 2 ... Printing mechanism part, 11 ... Main guide rod, 12 ... Subordinate guide rod, 13 ... Carriage, 14
... recording head, 15 ... ink cartridge, 17 ... main scanning motor, 18 ... drive pulley, 19 ... driven pulley, 20
.. Timing belt, 29 sub-scanning motor, 37 recovery device, 50 multi-valued image data, 51 processing means having a γ correction ROM, 52 half-tone processing means, 53 binary image data, 54 ... Recording head drive circuit means, 55
... temperature sensor, 56 ... temperature signal, 60 ... CPU, 61 ...
ROM, 62 RAM, 63 color processing circuit, 64 image memory, 65 parallel input / output (PIO) port, 66
.., Input buffer, 67, gate array (GA) or parallel input / output (PIO) port, 68, head drive circuit, 69, driver, 70, host, 71, operation panel.

Claims (6)

[Claims] 1. An image recording apparatus for recording an image with a recording head having a plurality of recording elements having nozzles for discharging ink, comprising: a temperature detecting unit for detecting a temperature of the recording head; A drive control unit for controlling an amount of ink ejected from each print element of the print head according to the temperature, wherein the drive control unit adjusts the detected temperature from a plurality of γ tables provided in advance. An image recording apparatus, which selects an appropriate γ table according to the change and changes an input image signal. 2. The image recording apparatus according to claim 1, further comprising one or more recording heads, wherein said recording heads are recording element groups for ejecting inks of different colors to a plurality of recording elements constituting said recording head, or different from each other. A plurality of recording heads for ejecting color inks, and a plurality of γ tables corresponding to each ink color are provided for each of the recording element groups for ejecting each color ink or for each of the recording heads. Item 2. The image recording apparatus according to Item 1. 3. An image recording apparatus for recording an image by a recording head having a plurality of recording elements having nozzles for discharging ink, wherein the image recording apparatus has a plurality of print modes having different dot diameters for printing. Temperature detecting means for detecting the temperature of the recording head, and controlling the amount of ink ejected from each recording element of the recording head for each print mode in accordance with the temperature detected by the temperature detecting means. An image recording apparatus, comprising: 4. The image recording apparatus according to claim 3, wherein the drive control unit is configured to select an appropriate one according to a temperature detected by the temperature detection unit from among a plurality of γ tables provided in advance for each of the print modes. An image recording apparatus for selecting an appropriate γ table and changing an input image signal. 5. The image recording apparatus according to claim 1, wherein the recording element includes a nozzle, an ink liquid chamber, and pressure generating means, and the recording head discharges ink by the pressure generating means. An image recording apparatus, which is an ink jet recording head. 6. An image recording method in which an image is recorded by a recording head having a plurality of recording elements having nozzles for discharging ink, a temperature detecting step of detecting a temperature of the recording head, and a temperature detected by the temperature detecting step. A driving control step of controlling an amount of ink ejected from each recording element of the recording head in accordance with the temperature, wherein the driving control step includes the step of: detecting the detected temperature from a plurality of γ tables provided in advance. An image recording method, wherein an appropriate γ table is selected according to the input image signal, and an input image signal is changed.