JP3126537B2 - Ink jet recording method and apparatus - Google Patents

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 recording characters and images by ejecting fine ink droplets toward a recording medium such as paper.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for recording characters and images on a recording medium such as paper, there is an impact-type recording technique for performing recording by pressing an ink ribbon containing ink toward a recording medium. In such a recording apparatus, when the number of recordings is increased, the amount of ink held in the ink ribbon decreases, and the density of the recorded image decreases, thereby informing the user of the life of the ink ribbon.

On the other hand, in an ink jet recording apparatus,
Compared to other recording devices, it has many advantages such as (1) high-speed recording (2) easy colorization (3) recording on plain paper (4) low noise (5) good recording quality ing.

[0004] Such an ink jet recording apparatus is generally constituted by a recording head for performing recording, and an ink cartridge which can store and replace ink for supplying ink to the recording head. ing.

In the above-described ink jet recording apparatus, when the number of recordings is increased, the remaining amount of the ink in the ink cartridge is reduced, and the recording becomes impossible due to shortage. For this reason, generally, the remaining amount of ink in the ink cartridge is monitored as needed, and when the amount of ink falls below a certain level, a lamp is lit or a message is displayed to inform the user that the remaining amount of ink is low.

[0006]

However, such a conventional ink jet recording apparatus monitors the remaining amount of the ink in the ink cartridge, and when the remaining amount of the ink becomes less than a certain amount, the user can exchange the ink cartridge or Even if the user is prompted to buy an ink cartridge, if the remaining amount of ink becomes equal to or less than the threshold value of the recordable ink amount, recording becomes suddenly impossible, and there is a problem that data during recording is lost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and after notifying a user of a decrease in the remaining amount of ink, can increase the number of recordable sheets and minimize data loss during recording. It is an object to provide an ink jet recording apparatus.

[0008]

[0009]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems uses a recording head for discharging ink, and performs image formation by discharging ink from the recording head toward a recording medium. An ink jet recording apparatus, comprising: an ink remaining amount detection unit for detecting a decrease in the remaining amount of ink in an ink storage unit communicating with the recording head; and an ink remaining amount detection signal from the ink remaining amount detection unit. Image density reducing means for lowering the density of a print image printed by the print head, wherein the image density lowering means is configured to reduce the density of the image ejected from the print head.
This is a means for reducing the ink ejection volume per droplet.

[0010]

The present invention also relates to an ink jet recording method for forming an image by using a recording head for discharging ink and discharging ink from the recording head toward a recording medium. An ink remaining amount detecting step for detecting a decrease in the ink remaining amount in the communicating ink storage unit, and an image for reducing the density of a recording image recorded by the recording head based on a detection result by the ink remaining amount detecting step. A density lowering step, wherein in the image density lowering step, an ink ejection volume per droplet ejected from the recording head is reduced.

[0012]

According to the above construction, even if the remaining amount of ink in the ink storage unit is reduced, the number of prints can be increased, and the user can be surely reduced the amount of remaining ink before losing print data. I can let you know.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an ink jet recording apparatus according to an embodiment of the present invention.

(First Embodiment) FIG. 2 is a perspective view of an ink jet recording apparatus according to the present invention.

The carriage 1 has an ink jet head 2 and a cartridge guide 3 mounted thereon, and can travel along guide shafts 4 and 5.

The recording paper 6 is fed into the main body by a paper feed roller 7, is sandwiched by a paper feed roller 8, a pinch roller (not shown), and a paper holding plate 9, and is conveyed to the front of the ink jet head 2 for recording. Is performed.

Two types of ink cartridges, a color ink cartridge 10 containing three colors of yellow, magenta and cyan, and a black ink cartridge 11 are separately inserted into the cartridge guide 3 and connected to the ink jet head 2.

FIG. 1 is a schematic diagram for explaining the structure of an ink jet recording head used in this embodiment.

Each nozzle 106 is provided with a corresponding heating element 104 (heater). When a predetermined energy is applied to the heater 104 by a head drive circuit, a state change due to film boiling in the ink. That is, a bubbling phenomenon occurs, and ink droplets are ejected from the ejection port 102.

The heater 104 is connected to the silicon substrate 101
Formed in the same manner as the semiconductor manufacturing process.
103 is a nozzle partition constituting each nozzle 106;
105 is a common liquid chamber for supplying ink to each nozzle 106, and 107 is a top plate.

The details of the driving pulse will be described with reference to FIG. A recording timing signal (a) and recording data corresponding to the recording density are input to the head drive circuit. According to the recording timing signal (a), first, in (b), the voltage V1 and the width T1
The first pulse (pre-pulse) of the rectangular wave
Is applied to At this time, bubbling contributing to the ejection of ink droplets does not occur near the heater 104 in the nozzle 106.
That is, ink ejection does not occur. The first pulse serves to heat the ink in the nozzle 106 and, in particular, reduce the viscosity of the ink. Subsequently, after a lapse of time T2 when the voltage is 0, a second rectangular pulse having a voltage V2 and a width T3 is applied to the heater 104. Here, the voltages of the first pulse and the second pulse are equal, that is, V1 = V2. The width of the second pulse is longer than the width of the first pulse, that is, T1 <T3. The second pulse is of a voltage and width that is sufficient for the applied electrical energy to cause bubbling in the nozzle 106 and for the ink to be ejected from the outlet 102.

FIG. 4A is a graph in which the characteristics of the pulse width of the pre-pulse T1 and the ejection ink volume Vd are plotted. In FIG. 1, it can be seen that the ink ejection volume changes according to the pulse width of T1. In this embodiment, by utilizing this characteristic, the pulse width of the pre-pulse T1 becomes smaller than the normal pulse width from the time when the remaining amount of ink in the ink cartridge becomes a certain amount or less and the remaining amount decreases. And
Reduce the ink ejection volume.

FIG. 4B is a graph in which the characteristics of the ejected ink volume Vd and the optical reflection density (OD value) of the recorded image are plotted.

From the graphs of FIGS. 4A and 4B, it is understood that the density of the recorded image changes according to the change of the pulse width of the pre-pulse T1.

FIG. 5 is a block diagram showing the electrical configuration of the ink jet recording apparatus according to this embodiment.

Referring to FIG. 5, a main controller 500 for controlling the entire recording apparatus comprises a CPU in the form of a microprocessor for executing a processing procedure, a program ROM storing a program indicating the processing procedure, and the like. It is connected to an ink remaining amount sensor 501, a motor driver 503D, a motor driver 502D, and a driver controller 510 for managing print image data. 5C is a recording head for ejecting cyan ink, 5M is a recording head for ejecting magenta ink, 5Y
Is a recording head that discharges yellow ink, and 5K is a recording head that discharges black ink. The motor driver 502 is controlled by the main controller 500.
D is a carriage motor 502 for driving the carriage 1
, And the motor driver 503D drives the feed motor 503 that conveys the recording medium.

Here, when the ink remaining amount sensor 501 detects a decrease in the amount of ink, the main controller 500
When it is determined that the remaining amount of ink is equal to or less than the first threshold value, the drive of the driver controller 510 is controlled, and based on the data in the drive data memory 510M for temporarily storing print image data, FIG. As shown in (1), a drive pulse in which the pulse width of the pre-pulse T1 is shorter than usual is applied to the printheads 5C, 5M, 5Y, and 5K via a head drive circuit 512 that transfers a drive signal and print data to the printhead.

As a result, the density of the recorded image becomes lower than usual. Also, the main controller 500
When it is determined based on the detection signal from the ink remaining amount sensor 501 that the ink remaining amount is equal to or smaller than a second threshold value which is still smaller than the first threshold value, FIG.
As shown in (d), drive control is performed so that a drive pulse with the pulse width of the pre-pulse T1 further reduced is output to the recording head. As a result, the density of the recorded image is further reduced. In addition, as a method of detecting the remaining amount of ink by the remaining ink sensor 501, a method of detecting a decrease in the remaining amount of ink in the ink storage unit by a magnitude of a current flowing between the two electrodes via the ink, A method of detecting by the pressure fluctuation of the ink flow path connecting the recording head, or a method of counting the number of recording dots and estimating the amount of used ink. Various known detection methods such as a detection method can be applied.

As described above, as the remaining amount of ink decreases,
By controlling the pulse width of the drive pulse applied to the heater 104, the density of the recorded image can be reduced, and the user can be notified that the remaining amount of ink is low.

(Second Embodiment) In the second embodiment,
The basic configuration of the ink jet recording apparatus is the same as that of the first embodiment, and the description is omitted.

FIG. 6A is a graph in which the characteristics of the heater drive voltage Vh and the ejection ink volume Vd are plotted. FIG. 6A shows that the ink ejection volume changes according to the heater drive voltage Vh. In the present embodiment, by utilizing this characteristic, the remaining amount of ink in the ink cartridge becomes equal to or less than a certain amount, and from the time when the remaining amount decreases,
The head drive voltage Vh is set lower than the normal head drive voltage Vh, and the ink ejection volume is reduced.

FIG. 6B is a graph plotting the characteristics of the ink ejection volume Vd and the optical reflection density (OD value) of the recorded image.

From the graphs of FIGS. 6A and 6B, it is understood that the density of the recorded image changes according to the change of the head drive voltage Vh.

FIG. 7 is a block diagram showing the electrical configuration of the ink jet recording apparatus according to this embodiment. Upon receiving a detection signal from the ink remaining amount sensor 501, the main controller 500 controls a head driving voltage Vh applied to the recording heads 5C, 5M, 5Y, and 5K from a head driving power supply 504, and the ink remaining amount becomes a predetermined threshold. When the value becomes equal to or less than the value, the magnitude of the head drive voltage Vh is made smaller than usual to lower the recorded image density.

As described above, by controlling the head drive voltage Vh applied to the heater 104, the density of the recorded image can be reduced, and the user can be notified that the remaining amount of ink has become small.

(Third Embodiment) In the third embodiment,
The basic configuration of the ink jet recording apparatus is the same as that of the first embodiment, and the description is omitted.

Further, in the ink jet recording apparatus shown in this embodiment, in order to obtain a stable recorded image, the recording head is provided with a temperature detecting means for detecting the temperature of the recording head and the recording head at a certain temperature when the temperature is low. A heating means for maintaining the temperature is provided.

FIG. 8A is a graph in which the control temperature of the ink jet recording head and the characteristics of the ejected ink volume Vd are plotted. In the figure, it can be seen that the ink ejection volume changes according to the control temperature of the print head. In this embodiment, by utilizing this characteristic, the control temperature of the print head is controlled by the normal control of the print head from the time when the remaining amount of ink in the ink cartridge becomes a certain amount or less and the remaining amount decreases. Make the temperature lower than the temperature and reduce the ink ejection volume.

FIG. 8B is a graph plotting the characteristics of the ink ejection volume Vd and the optical reflection density (OD value) of the recorded image.

From the graphs of FIGS. 8A and 8B, it is understood that the density of the recorded image changes in accordance with the change in the control temperature of the recording head.

FIG. 9 is a block diagram showing the electrical configuration of the ink jet recording apparatus according to this embodiment. In this embodiment, each recording head is provided with a temperature detecting means and a heating means (not shown), and upon receiving a detection signal from the ink remaining amount sensor 501, the main controller 500 drives and controls the head temperature control circuit 904. Then, based on a temperature detection signal detected by a temperature detection unit provided in the recording head, a heating unit provided in the recording head is controlled to control the recording head when the remaining amount of ink becomes equal to or less than a predetermined threshold value. The temperature is made lower than the normal control temperature to lower the recorded image density.

As described above, by controlling the control temperature of the ink jet recording head, the density of the recorded image can be reduced, and the user can be notified that the remaining amount of ink is low.

(Fourth Embodiment) In the fourth embodiment,
The basic configuration of the ink jet recording apparatus is the same as that of the first embodiment, and the description is omitted.

Generally, a printer that receives recording data from a host computer and records it on a recording medium includes:
A print mode according to the recording method is prepared according to the purpose. One of the printing modes is a draft printing mode.

FIG. 10 shows an example of the draft print mode. In FIG. 10, the description will be made using the letter A of the alphabet. FIG. 10A shows a configuration of recording data in a normal print mode, and FIG. 10B shows a case where pixel data to be recorded is not recorded every other pixel, and the number of recording pixels is reduced to about half. This is a mode in which the recording speed can be nearly doubled. At this time, since the number of recording pixels is reduced by half, the ink consumption of the inkjet recording apparatus is also reduced by about half. However, since the density of the recorded image decreases, the user operates a switch or the like as necessary to select the draft print mode.

In the present embodiment, the above-mentioned draft print mode is used, and when the amount of ink remaining in the ink cartridge falls below a certain value in the ink jet recording apparatus, the draft print mode or the number of recording pixels is automatically set. Means for shifting to a mode for automatically reducing the

FIG. 11 is a block diagram showing the electrical configuration of the ink jet recording apparatus according to this embodiment. In FIG. 11, reference numeral 513 denotes a data conversion circuit for processing / converting print data in accordance with an instruction from the main controller. Main controller 500 is ink remaining amount sensor 5
When the data conversion circuit 5 determines that the remaining amount of ink has become equal to or less than a predetermined threshold value in response to the detection signal
By controlling the driving of the recording head 13, the recording head is driven via the head driving circuit 512 in the above-described draft printing mode or the mode for automatically reducing the number of recording pixels to lower the recording image density.

As described above, in the ink jet recording apparatus, the density of the recorded image is reduced by reducing the number of recording pixels of the recording data, and the user is notified that the remaining amount of ink is low. Can be done.

(Other Embodiments) The above embodiments are not only executed independently and independently, but also, for example, after the first embodiment is carried out by the remaining amount of ink, the remaining amount of ink is further reduced. When lowered, it is also possible to carry out a combination of a plurality of embodiments, such as carrying out the fourth embodiment.

In the above embodiment, the ink jet recording technique utilizing film boiling generated in the ink has been described as an example. However, the present invention can be applied to other ink jet recording techniques such as a piezo method.

In each of the above-described embodiments, the ink remaining amount detection sensor can be provided for each color or for each ink cartridge. Then, after detecting a decrease in the remaining amount of ink, the print density is reduced when a color print head is used, when all four colors of yellow, magenta, cyan, and black are reduced, only a specific color is reduced. In some cases, only the color ink whose remaining ink amount has decreased may be reduced.

The present invention provides an excellent effect particularly in an ink jet recording head and a recording apparatus in which a flying droplet is formed by utilizing thermal energy in the ink jet recording method and recording is performed.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or the liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, heat energy is generated in the electrothermal transducer, and the recording head is driven. This is effective because film boiling occurs on the heat acting surface, and as a result, bubbles in the liquid (ink) corresponding to this drive signal one-to-one can be formed. The liquid (ink) flows through the ejection opening due to the growth and contraction of this bubble.
To form at least one droplet. When this drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the liquid (ink) having particularly excellent responsiveness can be obtained.
Discharge can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. still,
US Patent No. 4 of the invention relating to the temperature rise rate of the heat acting surface
If the conditions described in the specification of Japanese Patent No. 313124 are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting portion is arranged in a bending region, is also included in the present invention.

In addition, JP-A-59-123670, which discloses a configuration in which a common slit is used as a discharge portion of an electrothermal transducer for a plurality of electrothermal transducers, or absorbs pressure waves of thermal energy. The present invention is also effective as a configuration based on JP-A-59-138461, which discloses a configuration in which an opening corresponds to a discharge unit.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is determined by combining a plurality of recording heads as disclosed in the above specification. The present invention can exhibit the above-mentioned effects more effectively, though it may be either a configuration that satisfies the above requirements or a configuration as a single recording head that is formed integrally.

In addition, the print head is replaceable with a print head of a replaceable chip type, which can be electrically connected to the main body of the apparatus or supplied with ink from the main body of the apparatus, or is integrated with the print head itself. The present invention is also effective when a cartridge type recording head provided with an ink tank is used.

It is preferable to add recovery means for the recording head, preliminary auxiliary means, and the like because the effects of the present invention can be further stabilized. If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof, and printing Performing a preliminary ejection mode for performing another ejection is also effective for performing stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, and the recording head may be integrally formed or a combination of plural recording heads. The present invention is also extremely effective for an apparatus provided with at least one of full colors by color mixture.

In the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens at room temperature or is liquid, In general, in the ink jet method, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. What is necessary is just to be liquid.

In addition, the temperature rise due to thermal energy can be positively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or solidified in a standing state to prevent evaporation of the ink. Either ink may be used, or in any case, the ink may be liquefied by application of heat energy according to the recording signal and ejected as a liquid ink, or may already start to solidify when reaching the recording medium. The use of ink having a property of being liquefied for the first time by heat energy is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or Japanese Patent Application Laid-Open No. 60-71260, in which the porous sheet is opposed to the electrothermal converter while being held in a liquid or solid state in the concave portions or through holes of the porous sheet. It may be. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, the recording apparatus according to the present invention may be combined with a reader or the like in addition to the one provided as an image output terminal of an information processing device such as a word processor or a computer as described above. A copier, or a facsimile machine having a transmission / reception function may be used.

FIG. 12 is a block diagram showing a schematic configuration when the ink jet recording apparatus of the present invention is applied to an information processing apparatus having functions as a word processor, a personal computer, a facsimile apparatus, and a copying apparatus.
In the figure, reference numeral 1201 denotes a control unit for controlling the entire apparatus, including a CPU such as a microprocessor and various I / O ports;
Control signals and data signals are output to each unit, and control is performed by inputting control signals and data signals from each unit.
A display unit 1202 displays various menus, document information, image data read by the image reader 1207, and the like on this display screen. Reference numeral 1203 denotes a transparent pressure-sensitive touch panel provided on the display unit 1202. By pressing the surface with a finger or the like,
Item input, coordinate position input, and the like can be performed on the display unit 1202.

Reference numeral 1204 denotes an FM (Frequency M).
music information generated by a music editor or the like in the memory unit 1210 or the external storage device 12.
Digital data is stored in the memory 12 and read out from the memory or the like to perform FM modulation. The electric signal from the FM sound source unit 1204 is converted into an audible sound by the speaker unit 1205. The printer unit 1206 is the one to which the recording device according to the present invention is applied as an output terminal of a word processor, a personal computer, a facsimile machine, and a copying machine.

Reference numeral 1207 denotes an image reader unit for reading and inputting original data photoelectrically, which is provided in the middle of the original transport path, and reads various originals in addition to facsimile originals and copy originals. Reference numeral 1208 denotes a facsimile transmission / reception unit for facsimile transmission of original data read by the image reader unit or 1207, and reception and decoding of a transmitted facsimile signal, and has an external interface function. Reference numeral 1209 denotes a telephone unit having various telephone functions such as a normal telephone function and an answering machine function. 121
Reference numeral 0 denotes a ROM for storing a system program, a manager program, other application programs, and the like, a character font, a dictionary, and the like; a RAM for storing application programs and character information loaded from an external storage device 1212; This is a memory unit including

Reference numeral 1211 denotes a keyboard for inputting document information and various commands. Reference numeral 1212 denotes an external storage device using a floppy disk, a hard disk, or the like as a storage medium. The external storage device 1212 stores character information, music or voice information, user application programs, and the like.

FIG. 13 is an external view of the information processing apparatus shown in FIG. In the figure, reference numeral 1301 denotes a flat panel display using a liquid crystal or the like, which displays various menus, graphic information, document information, and the like. A touch panel is provided on the display 1301, and coordinates input and item designation input can be performed by pressing the surface of the touch panel with a finger or the like. 1302 is a handset used when the device functions as a telephone.

The keyboard 1303 is detachably connected to the main body via a cord, and can input various character information and various data. Also, this keyboard 13
03 is provided with various function keys 1304 and the like. 1
Reference numeral 305 denotes a floppy disk insertion port.

Reference numeral 1307 denotes a paper placing portion on which a document to be read by the image reader portion 1207 is placed, and the read document is discharged from the rear of the apparatus. In the case of facsimile reception or the like, recording is performed by the ink jet printer 1307.

The display 1301 may be a CRT, but is preferably a flat panel such as a liquid crystal display using a ferroelectric liquid crystal. This is because the weight can be reduced in addition to the reduction in size and thickness. When the information processing device functions as a personal computer or a word processor,
12, various information input from a keyboard unit 1211 is processed by a control unit 1201 according to a predetermined program, and is output as an image to a printer unit 1206. When functioning as a receiver of the facsimile apparatus, facsimile information input from the facsimile transmission / reception unit 1208 via a communication line is subjected to reception processing by the control unit 1201 according to a predetermined program, and is output to the printer unit 1206 as a reception image.

When functioning as a copying apparatus, a document is read by an image reader unit 1207, and the read document data is output as a copied image to a printer unit 1206 via a control unit 1201. When functioning as a transmitter of the facsimile machine, the original data read by the image reader unit 1207 is transmitted to the control unit 1.
After being subjected to transmission processing according to a predetermined program by 201, it is transmitted to a communication line via a facsimile transmission / reception unit 1208. Note that the above-described information processing apparatus may be an integrated type in which an ink jet printer is built in the main body as shown in FIG. 14, and in this case, portability can be further improved. In the figure, parts having the same functions as those in FIG. 13 are denoted by the corresponding reference numerals.

By applying the recording apparatus of the present invention to the multifunctional information processing apparatus described above, a high-quality recorded image can be obtained, so that the function of the information processing apparatus can be further improved. Become.

[0074]

As described above, according to the present invention, in the ink jet recording apparatus, the amount of ink remaining in the ink storage section is monitored, and the energy applied to the recording head is controlled when the amount of ink falls below a certain level. By controlling the control temperature of the print head or reducing the number of print pixels of print data, the density of the print image can be reduced, and the user can be reliably notified that the remaining amount of ink is low. Also,
In order to reduce the amount of ink consumption, it is possible to increase the amount of recording after the remaining amount of ink in the ink storage unit is reduced.
Further, in recent years, due to the remarkable spread of personal computers, compact and inexpensive recording apparatuses have been demanded in recording apparatuses. There is no need to provide a lamp or a display for displaying a message to notify the user of the decrease, and the user can be reliably informed of the decrease in the remaining amount of ink. Therefore, the recording apparatus can be provided at low cost. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a structure of an ink jet recording head.

FIG. 2 is a perspective view of an ink jet recording apparatus according to the present invention.

FIG. 3 is a timing chart showing a driving pulse of the inkjet recording head.

FIG. 4 is a graph showing the characteristics of a printhead drive pre-pulse T1 and the volume of ejected ink, and the graph showing the characteristics of the volume of ejected ink and the density of a recorded image formed on a recording medium.

FIG. 5 is a block diagram illustrating an electrical configuration of the inkjet recording apparatus according to the first embodiment.

FIG. 6 is a graph showing characteristics of a recording head drive voltage Vh and a volume of ejected ink, and a graph showing characteristics of an ejected ink volume and a density of a recorded image formed on a recording medium.

FIG. 7 is a block diagram illustrating an electrical configuration of an inkjet recording apparatus according to a second embodiment.

FIG. 8 is a graph showing the characteristics of the control temperature of the print head and the volume of the ejected ink, and the graph showing the characteristics of the volume of the ejected ink and the density of a print image formed on a print medium.

FIG. 9 is a block diagram illustrating an electrical configuration of an inkjet recording apparatus according to a third embodiment.

FIG. 10 is a diagram for explaining a draft print mode.

FIG. 11 is a block diagram illustrating an electrical configuration of an inkjet recording apparatus according to a fourth embodiment.

FIG. 12 is a block diagram illustrating a schematic configuration in a case where the inkjet recording apparatus of the present invention is applied to an information processing apparatus.

FIG. 13 is an external view of an information processing apparatus.

FIG. 14 is an external view illustrating another example of the information processing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Carriage 2 Print head 3 Cartridge guide 4 Guide axis A 5 Guide axis B 5C Cyan recording head 5M Magenta recording head 5Y Yellow recording head 5K Black recording head 6 Recording paper 7 Paper feed roller 8 Paper feed roller 9 Paper press plate 10 Color cartridge Reference Signs List 11 black cartridge 101 silicon substrate 102 ink discharge port 103 nozzle partition 104 heating element (heater) 105 common liquid chamber 106 nozzle 107 top plate 500 main controller 501 for controlling the entire recording apparatus 501 sensor for detecting remaining ink amount 502 recording head Motor 502D for driving a carriage on which a printer is mounted Motor driver 503 for driving a carriage motor 503 Feed motor for conveying a recording medium 503D Feed motor Motor driver 504 for controlling the head drive voltage for controlling the head drive voltage according to the instruction of the main controller 510 driver controller 510M for managing the recorded image data data memory 512 for temporarily storing the recorded image data 512 drive signal and recording for the recording head Head drive circuit 513 for transferring data Data conversion circuit for processing / converting print data in accordance with instructions from main controller 904 Head temperature control circuit for monitoring head temperature and controlling print head temperature to control temperature instructed by main controller

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B41J 2/175 B41J 2/05 B41J 2/125 B41J 2/205

Claims (14)

(57) [Claims] 1. An ink jet recording apparatus for forming an image by using a recording head for discharging ink and discharging ink from the recording head toward a recording medium, wherein the recording head communicates with the recording head. An ink remaining amount detecting unit for detecting a decrease in the remaining amount of ink in the ink storage unit, and a density of a recording image recorded by the recording head based on an ink remaining amount detecting signal from the ink remaining amount detecting unit. An ink jet recording apparatus, comprising: an image density lowering unit that lowers an image density, wherein the image density lowering unit is a unit that reduces an ink ejection volume per droplet ejected from the recording head. 2. The method according to claim 1, wherein when the remaining amount of ink in the ink storage unit is equal to or less than a predetermined amount, the image density reducing unit reduces the ink ejection volume to a first volume. When the remaining amount of ink becomes equal to or less than a second predetermined amount that is smaller than the predetermined amount, the image density lowering unit reduces the ink ejection volume to a second volume smaller than the first volume. Claims characterized by the following:
2. The inkjet recording apparatus according to 1. 3. An ink storage section provided for each color of each ink and communicating with each of the plurality of recording heads has the ink remaining amount detecting means. 2. The ink jet recording apparatus according to claim 1, wherein the ink ejection volume of a recording head communicating with the ink reservoir when the remaining amount of ink in the reservoir is equal to or less than a predetermined amount is reduced. 4. An ink storage section provided for each color of each ink and communicating with each of the plurality of recording heads has the ink remaining amount detecting means, and includes any one of the plurality of recording heads. When the remaining amount of ink in the ink storage unit becomes equal to or less than a predetermined amount in the ink storage unit communicating with the print head, all the ink ejection volumes of the plurality of print heads are reduced. The inkjet recording apparatus according to claim 1. 5. The ink jet recording apparatus according to claim 1, wherein the reduction of the ink ejection volume by the image density lowering unit is performed by shortening a pulse width of a driving pulse applied to the recording head. . 6. The ink jet recording apparatus according to claim 1, wherein the reduction of the ink ejection volume by the image density lowering means is performed by reducing a driving pulse voltage of a driving pulse applied to the recording head. . 7. The ink jet recording apparatus according to claim 1, wherein the ink ejection volume is reduced by the image density lowering unit by lowering the temperature of the recording head. 8. The recording head according to claim 1, wherein the recording head ejects ink by using thermal energy, and is an ink jet recording head including a thermal energy converter for generating thermal energy to be applied to the ink. Item 1
7. The ink jet recording apparatus according to any one of claims 1 to 6. 9. An image forming apparatus, comprising: the ink jet recording apparatus according to claim 1; and a document image reading unit. 10. An image forming apparatus comprising: the ink jet recording apparatus according to claim 1; and means for transmitting and / or receiving image information. 11. The image forming apparatus according to claim 10, further comprising a document image reading unit. 12. An image forming apparatus comprising: the inkjet recording apparatus according to claim 1; and recording signal input means. 13. The image forming apparatus according to claim 12, wherein the recording signal input means is a keyboard. 14. An ink jet recording method for forming an image by using a recording head for ejecting ink and ejecting ink from the recording head toward a recording medium, comprising: an ink reservoir communicating with the recording head. An ink remaining amount detecting step for detecting a decrease in the remaining amount of ink in the unit, and an image density lowering step of reducing the density of a recording image recorded by the recording head based on a detection result of the ink remaining amount detecting step. An ink jet recording method, comprising: in the image density lowering step, decreasing an ink ejection volume per droplet ejected from the recording head.