JPH0939253A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the increase of a power source and to improve the life of a head board and hence a recording head by providing a controller for driving a heating element to set and output the duty ratio of a pulse signal to hold the temperature of the head at a predetermined temperature. SOLUTION: A temperature sensor and environmental temperature detecting means for detecting the head temperature and environmental temperature detecting means are provided in the recording head of the ink jet recorder, and the detected temperatures are input to a controller. The drives of subheaters 101B, 101C on a heater board 100 provided at the head are respectively controlled based on the detected temperatures. In this case, the temperature control is conducted, for example, by dividing the time into three stages, and the duty ratios of the pulse signals to be applied to the subheaters 101B, 101C of high speed temperature rising time zone, intermediate speed temperature rising time zone and set temperature holding time zone at the time of starting to record are varied. Thus, the power consumptions of the subheaters 101B, 101C are rationally suppressed to the minimum limit, and the life of a semiconductor element on a circuit board is prolonged.

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, and more particularly to an ink jet recording apparatus having a recording head having a plurality of heat generating elements as an ejection energy generating element in addition to an element generating heat energy.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers, word processors, facsimiles, etc. in offices, printers of various recording systems have been developed as output devices of these devices. Among them, the ink jet recording method is suitable for personal use in an office because it has low recording noise, enables high-quality recording on various recording materials, and is small in size. Among the ink jet recording methods, the thermal method, which has a high drive response, has become one of the mainstream. In such a recording method, an electric signal is converted into heat by a heating element in a recording head to cause the film to boil the ink, and the pressure caused by the boiling is used to eject the ink toward a recording material, and the ink droplets landed on the recording material. A dot is formed by the spread of. By the way, in such a recording method, the amount of ejected ink changes depending on the viscosity of the ink in the ink ejecting portion. That is, the viscosity of the ink increases as the temperature becomes lower, and the fluid resistance at the contact portion between the ink and the surrounding members forming the ink ejection portion increases, which significantly reduces the kinetic energy generated by foaming. become. Then, when the amount of ink ejected falls below a predetermined amount, the recorded image cannot be reduced in density and a sufficient dot area cannot be obtained, and the quality of the recorded image is impaired. Therefore, in order to solve such a problem, Japanese Patent Laid-Open No.
As described in Japanese Unexamined Patent Publication No. 8-220757, an ejection heating element (hereinafter referred to as an ejection heater) is attached to the recording head.
In addition to the above, by providing an auxiliary heating heating element (hereinafter referred to as a sub-heater) that is an auxiliary heating means for heating the surrounding ink ejection portion constituting member, the temperature of the ink is raised and the above-mentioned problem is solved. are doing. According to such a configuration, the sub-heater is an electrothermal converter manufactured by a film forming technique on a silicon chip, like the ejection heater, so that it is possible to realize heat retention of the recording head at low cost. .

[0003]

However, the above-mentioned conventional example requires a power source capacity capable of heating both the discharge heater and the sub-heater at the same time, and when the heating is performed at the same time, the load on the silicon chip which is the recording head wiring substrate is increased. The larger size shortened the functional life of the silicon chip.

An object of the present invention is to solve such a conventional problem and to rationally control the heating of the sub-heater for auxiliary head heating, thereby suppressing an increase in power supply and pulling the head substrate and recording head. An object of the present invention is to provide an ink jet recording apparatus capable of achieving a long life.

[0005]

In order to achieve the above object, the present invention provides a plurality of electrothermal conversion elements for generating ink ejection energy on a wiring substrate of a recording head,
At least two heating elements for controlling the temperature of the recording head are provided, and a duty ratio of a pulse signal for driving the heating element is set and output so as to keep the temperature of the recording head at a predetermined temperature. And a control circuit for driving the heating element.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION According to an embodiment of the present invention,
The control circuit for driving the heating element raises the temperature of the print head to a predetermined temperature suitable for performing the printing operation, and sets the duty ratio of the pulse signal to maintain the predetermined temperature and drives the heating element. It outputs a signal and has at least two heating elements, and the one that needs to be raised in temperature is driven according to the recording state, so power is consumed unnecessarily and each element on the wiring board It is possible to prevent shortening the life of the.

[0007]

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

FIG. 1 shows a structural example of an ink jet recording apparatus IJRA to which the present invention can be applied. The case of this example is an example of an inkjet recording apparatus IJRA in which the ink head cartridge IJC is mounted on the carriage HC to perform recording. Here, 5000 is a platen capable of feeding the sheet P as a recording material, and 5002 is a platen 500.
A sheet retainer for holding the sheet P between 0 and 500, a guide shaft 5003 for guiding the carriage HC along the sheet P,
Reference numeral 5004 has a lead groove 5005 screwed into the carriage HC, and is a lead screw rotationally driven by a drive motor 5013.
This is a gear for transmitting the driving force due to the forward and reverse rotations of 1 to the lead swallow 5004. The carriage HC moves in the directions of arrows a and b.
Reference numeral 8 denotes a home position detecting means including a photocoupler. When the carriage HC moves to this position, the pin 5006 provided on the carriage HC is detected by the photocouplers 5007 and 5008, and the rotation direction of the drive motor 5013 is changed. Can be switched.

Reference numeral 5015 denotes a cap member 5016, which is movable with the cleaning blade 5017 in this position in a direction orthogonal to the moving direction of the carriage HC, 5018 is a support member thereof, and 5020 is a movement of the carriage HC. The cam member is engaged with this and is involved in starting suction by the recovery means. It should be noted that the series of moving operations during the recovery operation are performed by utilizing the driving force of the drive motor 5013 by the switching operation by the clutch mechanism. 5023 is a cap member 5016
And the peripheral portion is in close contact with the ink ejection surface of the recording head IJH of the ink head cartridge IJC when the recovery operation is sucked.

Although not shown here, the recording head IJH is provided with a temperature sensor 110 for detecting the head temperature as shown in FIG. 1, and the ink jet recording apparatus has an environmental temperature detecting means for detecting the environmental temperature. 12
0 is provided, and the control unit 13
Each detected temperature is input to 0 as a signal. The control unit 130 has a CPU function, and has a ROM, a RAM as a recording device (not shown), and a timer. Therefore, the control unit 130 controls the driving of the sub-heaters 101B and 101C shown in FIG. 3 in order to control the temperature of the recording head IJH based on these input detected temperatures as described later. Further, the control unit 130 controls the drive of the drive motor 5013 and the sheet feed motor 5030 (see FIG. 1) by the carriage according to a predetermined routine, and also controls the recording operation by the recording head IJH.

FIG. 2 shows the details of the recording head, and a heater board 100 formed by a semiconductor process is provided on the upper surface of the support 300. The heater board 100 is provided with a heater (sub-heater) (not shown here) for temperature adjustment, which will be described later, for heating and adjusting the temperature of the print head IJH formed by the same semiconductor process. In the wiring board arranged on the body 300, the wiring board 200 is electrically connected to the temperature adjustment heater and the discharge (main) heater (not shown) by wire bonding or the like.

Here, 400 is an ink ejection port, and 50
Reference numeral 0 is a spring member for fixing the grooved top plate member having the ink discharge port 400 to the support body 300 together with the heater board 100, 600 is an ink supply member, and 800 is a lid for integrally fixing the ink jet unit IJU with the ink tank IT. It is a member.

FIG. 3 shows a recording head IJ applied to this embodiment.
The heater board 100 of H is shown typically. Where 10
1B and 101C are two temperature control sub-heaters, 101A is an ejection (main) heater, and 102 is a printing element array including a main heater, ink ejection ports, and liquid paths. Further, 103 is a drive element group, which is the heater 1 described above.
01A to 101C, the recording element array 102, and the driving element group 103 are formed on the same wiring board 200 in the positional relationship shown in FIG. By arranging each element on the same substrate 200 in this way, the head temperature can be handled and controlled efficiently, and the head IJH can be made compact and the manufacturing process can be simplified. In the figure, the outer peripheral wall 1 of the top plate for separating an area filled with ink and an area not filled with ink on the heater board 100.
04 is shown shaded.

Subsequently, according to FIG. 4, the sub-heaters 101B and 101C on the heater board 100 and the main heaters 101A (herein, when 15 recording elements are provided, the heaters corresponding to the individual elements are denoted by Seg1 to Seg15). The configuration of the drive circuit (appended) is described.

Here, C1 is a head driver consisting of a 15-bit transistor array, C2 is an AND gate provided corresponding to each main heater 101A, C3 is a main heater Seg1 to Se via the head driver C1.
It is provided to drive g15 separately, and BEN0 and BE
A decoder having two block enable input terminals of N1, C4 is a latch circuit, and C5 is a shift register. In this example, the color ink is ejected by the recording elements corresponding to the heaters Seg1 to Seg9, and the heater Se
The circuit configuration on the heater board 100 of the inkjet recording head IJH, which performs recording by ejecting black ink by the recording element corresponding to g10 to Seg15, is shown. HENBB is a heat enable terminal during black recording, and HENBC is color recording. It is a heat enable terminal at the time. Further, SUBHB and SUBHC respectively use the sub-heater 101B for black recording and the sub-heater 101C for color recording as drivers 201B and 2B.
A heat signal driven via 01C, and a generation circuit of the heat signals SUBHB and SUBHC will be described later. Furthermore, in FIG. 4, BEN0, BEN1
Is a block enable signal input terminal, SDT is a serial data signal, SCK is a serial clock signal, and RESE
T is a reset signal input terminal and LATCH is a latch signal input terminal.

FIG. 5 shows heat signals SUBHB and SUBHC.
An example of the configuration of the generator circuit of FIG. Here, 51 is a circuit for outputting a heat signal according to a timing chart described later (hereinafter referred to as a heat signal output circuit),
On its input side, data signals D0 to D15 and write signal N
WR, chip select signal NCS, heater start signal HT
A terminal for CYCL is provided. 52 is a selector circuit, 53 is an AND gate for outputting drive signals for the sub-heaters 101B and 101C, 54 is an inverter 55, 5
An AND gate to which the black recording heat signal HENBB and the color recording heat signal HENBC are input via 6, and PDT is a heat enable signal input to the AND gate 53.

Next, a basic operation procedure of temperature control of the sub heater according to the present invention will be described.

In the present invention, the temperature control of the sub-heater is temporally divided into three stages from T1 to T3, of which T1 is the high-speed temperature rise time zone at the start of recording, and T2.
7 is a medium-speed temperature rise time zone, and T3 is a set temperature holding time zone during the recording operation. The operation procedure and the state of temperature change in the print head IJH are shown in the flowchart of FIG. 6 and FIG.
The description will be made with reference to the graph shown in FIG.

First, when the power is turned on in step SD1, an initialization process is performed in step SD2, and a recording start command is awaited in step SD3. Then, in response to the start command, the process proceeds to step SD4 and the environmental temperature is obtained from the environmental temperature detecting means 120 (see FIG. 1). Then, in step SD5, the target rising temperature of the recording head IJH is set. For setting the target rising temperature with respect to the environmental temperature, for example, a table as shown in Table 1 below is prepared in the control unit 130. Then, a table like this may be looked up.

[0020]

[Table 1]

However, when the setting is completed, the process proceeds to step SD6, where the driving conditions of the sub-heaters 101B and 101C in each time zone of T1 to T3 are set, and then in steps SD7 and SD8 below. Of the driving conditions, the sub heaters 101B and 101 are operated under the condition of the T1 time zone.
C is driven, and in steps SD9 and SD10, under the driving conditions of the T2 time zone, and in steps SD11 and SD.
In 12, the sub heater 1 is driven under the driving condition of the T3 time zone.
The drive of 01B and 101C is controlled. Note that FIG. 7 shows an example in which the target temperature is set to 10 ° C.

Details of drive control of the sub-heaters 101B and 101C in each of the time zones T1 to T3 will be described below with reference to FIG.

(A) Control in high-speed temperature rising time period T1 First, the B / C selection signal input to the selector 52 is set to "0" or "1", and NCS (chip select signal), NWR (write signal) and D0 are set. The duty ratio (for example, 95% duty) that enables high-speed temperature rise is set by the control lines from D15 to D15 (data signal). Then, by setting the heat enable signal PDT to "1", the heat signal SUBH having a high duty ratio is changed to the heater activation signal H.
It is output in the cycle of TCYCL. Then, if heating is finished in the time zone T1 preset corresponding to the target elevated temperature and the environmental temperature, the signal PDT is set to "0" and the heating in the time zone T1 is finished.

(B) Control in medium-speed temperature rise time zone T2 Similarly to the case of control in time zone T1, the duty ratio (for example, 60% duty) capable of medium-speed temperature rise is set and then preset. The heating is finished in the time period T2 during which the heating is performed. Since recording is not started in any of the above time zones T1 and T2, both the black recording heat signal HENBB and the color recording heat signal HENBC are kept unchanged at "0".

(C) Control in recording time zone T3 First, the case where recording is performed by both black and color recording elements will be described.

In this case, the B / C selection signal is set to "0" and the duty ratio corresponding to the recording is set, but by setting the heat enable signal PDT to "1", the heat signal of FIG. As indicated by AB and AA surrounded by broken lines in the SUBHON (B / C = 0) waveform, heat is generated in response to the input of the black recording heat signal HENBB and the color recording heat signal HENBC to the selector 52 shown in FIG. The signal rises and falls, its duty ratio is secured in accordance with the cycle of the heater start cycle signal HTCYCL, and the temperature adjustment sub-heaters 101B and 101
Heating with C is performed. Here, the signals HENBB, H
Each of the ENBC and SUBHON signals is for heating in the rising "1" state. In this case, the heat enable signal PDT falls when the number of ejected recording elements becomes ⅕ or more of the total number of recording elements, and is controlled by the control unit 130 to stop the heating by the sub-heaters 101B and 101C. With the heater control including such control, the temperature of the printhead IJH can be kept close to the target temperature as shown at T7 in the time zone T3 during the printing operation. Further, it goes without saying that the control unit 130 can control so that the duty ratio can be changed according to the change in environmental temperature and the heat history.

Next, the control in the recording time zone T3 when recording is performed only by the recording element for black will be described.

In this case, if the B / C selection signal is set to "1" and the heat enable signal PDT is set to "1" after setting the duty ratio corresponding to such recording, the heat signal SUBHON (B / As shown by BB and BA surrounded by a broken line in the waveform of C = 1), the black recording heat signal HENBB rises, and rises in response to the rising.
Although the heat signal SUBHON is output so as to fall, the heat signal SUBHON is not output by the AND gate 53 during the rising. At the fall of the heat signal, the heat signal output circuit 51 stops the counter that measures the heating time. The other heating control operations are the same as those described above, and the description thereof will be omitted.
In FIG. 8, DTNB is a number indicating to which recording element the serial data is supplied.

Next, the structure of the heat signal generating circuit of the sub-heaters 101B and 101C according to the second embodiment of the present invention will be described with reference to FIG.

In the circuit configuration according to the present embodiment, heat signal output circuits 91 and 92 are provided for each sub-heater. 93B is an AND gate that outputs a heat signal SUBHB for driving the sub-heater 101B, and 93C is an AND gate that outputs a heat signal SUBHC for driving the sub-heater 101C. Also, 94B and 94C
Is an inverter. In this example, as shown in FIG. 10, by finely controlling both the temperature around the sub-heater 101B and the temperature around the sub-heater 101C in the print head IJH, the sub-heater during black printing, color printing, and both printings 101B, 1
The ON / OFF control of 01C is performed more rationally. In this case, although not shown, it is needless to say that the printhead IJH is provided with a temperature sensor so that the temperature in the vicinity of each subheater can be detected. .

The other details of FIG. 10 are the same as those described above with reference to FIG. 7 and will not be described. FIG. 11 is a timing chart of output signals from the respective parts according to the second embodiment. Where PDTB
And PDTC are black recording heat signals HENBB
And an enable signal for the color recording heat signal HENBC.

Details of drive control of the sub-heaters 101B and 101C in each of the time zones T1 to T3 according to this embodiment will be described with reference to FIGS. 9 to 11.

(A) Control in high-speed temperature rising time zone T1 In this case, since the sub-heaters 101B and 101C are output via the individual heat signal output circuits 91 and 92, a duty ratio (for example, 95) capable of high-speed temperature rising. In setting the (% duty), there is no difference from the control operation described in the first embodiment except that the chip select signals NCSB and NCSC individually input to the circuits 91 and 92 are involved.

(B) Control in medium-speed temperature rise time zone T2 With respect to this control as well, the setting of the duty ratio (for example, 65%) suitable for medium-speed temperature rise and the following operation procedure have been described in the first embodiment. The description will not be repeated without changing.

(C) Control in the recording time zone T3 In this embodiment, the control in the time zone T3 is different from that in the first embodiment, and the sub heater 101B output through the heat signal output circuit 91 and the AND gate 93B. Heat signal SUBHB and heat signal SUBHC output via the heat signal output circuit 92 and the AND gate 93C
And will be explained individually.

Regarding the output of the heat signal SUBHB, the duty ratio thereof is set by the heat signal output circuit 91 so as to correspond to the recording as described above. After that, the heat enable signal PDTB is shown in FIG. When it becomes "1", the heat signal SUBHB for the sub-heater 101B falls and rises in response to the rise and fall of the black recording heat signal HENBB for each cycle of the heat cycle signal HTCYCL. Thus, 10
The heating operation by the sub-heater 101B is performed only while the 1B heat signal SUBHB rises.

Similarly, regarding the output of the heat signal SUBHC, when the heat enable signal PDTC becomes "1" as shown in FIG. 11, the heat cycle signal HTCY is output.
Color recording heat signal HENB for each CL cycle
The heat signal SUBHC for the sub-heater 101C rises and falls according to the fall and rise of C. Thus, the sub-heater 101 is provided only during the rising of the heat signal SUBHC.
The heating operation by C is performed. The heat signal SUB
In either case, HB or SUBHC is not output when the heat enable signal PDTB or PDTC is "0". Furthermore, the heat enable signal PDTB
In both PDTC and PDTC, the number of recording elements that perform ejection is 1
When it becomes / 5 or more, it becomes “0” and the sub-heaters 101B, 1
The heating by 01C is stopped.

In the embodiment described above, two sub-heaters are provided on the heater board of one print head, and print elements for ejecting black ink and color ink are wired on the same line to the print head. Although the application example to the inkjet recording apparatus has been described, the application of the present invention is not limited to this. For example, it is needless to say that the present invention can be applied not only to a mono-color inkjet recording device and a serial printer but also to a full-line inkjet recording device, and the number of sub-heaters is not limited to two, for example, three. It may be more than. Further, the present invention can be applied to an inkjet recording device in which the recording head is kept at a predetermined temperature regardless of the environmental temperature.

[0039]

As described above, according to the present invention, a plurality of electrothermal converting elements for generating ink ejection energy on the wiring substrate of the recording head and the temperature of the recording head are controlled. And a heating circuit for driving a heating element for setting the duty ratio of a pulse signal for driving the heating element so as to keep the temperature of the recording head at a predetermined temperature. Since the print head can always be kept in the optimum temperature range for printing via the wiring board, the power consumption by the sub-heater driven for heating can be reasonably and minimized. In addition, the life of the semiconductor element provided on the wiring board can be extended.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration example of an inkjet recording apparatus according to the present invention.

FIG. 2 is an exploded perspective view showing a configuration example of a unit incorporating a recording head to which the present invention can be applied.

FIG. 3 is a plan view showing an arrangement of each element on a wiring board of the recording head according to the present invention.

FIG. 4 is a block diagram showing a circuit configuration on a wiring board according to the present invention.

FIG. 5 is a block diagram showing a configuration of a heat signal output circuit according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing a procedure of control operation according to the present invention.

FIG. 7 is a characteristic curve diagram for explaining temperature control of the recording head according to the first embodiment of the present invention.

FIG. 8 is a timing chart of signals generated by various parts according to the first embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a heat signal output circuit according to a second embodiment of the present invention.

FIG. 10 is a characteristic curve diagram for explaining the temperature control of the recording head according to the second embodiment of the present invention.

FIG. 11 is a timing chart of signals generated by various parts according to the second embodiment of the present invention.

[Explanation of symbols]

 51, 91, 92 Heat signal output circuit 52 Select circuit 53, 54, 93B, 93C AND gate 55, 56 Inverter 100 Heater board 101A (ink) ejection (main) heater 101B, 101C (for temperature control) sub-heater 102 Recording element array 110 temperature sensor 120 environment temperature detecting means 130 control unit 200 wiring board C1 head driver C2 AND gate C3 decoder C4 latch circuit C5 shift register T1 to T3 time zone D0 to D15 data signal IJH recording head HC carriage BEN0, BEN1 block enable signal input Terminal SUBHB, SUBHC, SUBHON Heat signal PDT, PDTB, PDTC Heat enable signal HENBB, HENBC Recording heat enable terminal

Claims (5)

[Claims] 1. A printhead includes a plurality of electrothermal conversion elements for generating energy for ejecting ink on a wiring substrate of the printhead, and at least two heating elements for controlling the temperature of the printhead, An inkjet recording apparatus comprising: a heating element driving control circuit for setting and outputting a duty ratio of a pulse signal for driving the heating element so as to keep the temperature of the recording head at a predetermined temperature. 2. The control circuit for driving the heating element supplies a pulse signal for driving at least one of the two heating elements while a predetermined number or more of the plurality of electrothermal conversion elements are being driven. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is controlled so as to stop. 3. The recording head has means for dividing the ejection port group into a plurality of blocks and managing the division, and the control circuit for driving the heating element is a predetermined one of the blocks of the plurality of ejection port groups. 3. The ink jet recording apparatus according to claim 1, wherein the driving of the heating elements arranged on the block side on which a number of inks are ejected is stopped. 4. A means for detecting an environmental temperature is provided in the vicinity of the recording head, and the control circuit for driving the heating element is configured to detect the ambient temperature of the recording head based on the temperature detected by the means for detecting the circulation temperature. The ink jet recording apparatus according to claim 1, wherein the predetermined temperature is set. 5. A head temperature detecting means for detecting the temperature of the recording head itself is provided, and the control circuit for driving the heating element controls the recording head based on the temperature detected by the head temperature detecting means. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is controlled to maintain a predetermined temperature.