JP6789679B2 - Heat retention control method for recording device and recording head - Google Patents

Description

The present invention relates to a method for controlling heat retention of a recording device and a recording head, and in particular, a recording device and a recording head that eject ink droplets from each ink ejection port provided on the recording head based on image data and record an image on a recording medium. Regarding the heat retention control method.

High-speed and high-quality image formation is required for an inkjet recording device, and in order to stably eject ink droplets forming an image, a plurality of electrothermal converters (heaters) that eject ink droplets are required. It is necessary to properly manage the heat retention of the recording head provided with the above. The heat retention management generally detects the temperature of the recording head by a diode sensor provided in the recording head, and controls to heat the recording head by using a sub-heater provided in the recording head according to the detected temperature. That is included.

Then, by increasing the number of sub-heaters and finely controlling the temperature distribution in the recording head, higher quality image formation is realized. However, in this case, if the number of sub-heaters to be controlled is increased, the processing load also increases as the number of sub-heaters to be controlled increases. Therefore, in image formation that requires high-speed processing, there is concern about the time required for the heat retention control itself of the recording head. Will be done.

Therefore, in Patent Document 1, the effective number of pixels to be recorded is counted and the effective pixel ratio is measured based on the recording data to be used for printing which is stored in the memory in the recording device. Then, the heat retention control of the recording head during recording is executed only when the effective pixel ratio is equal to or less than a predetermined value. As a result, it is possible to predict how to keep the heat of the recording head from the recording data in almost real time, and execute the heat retention control of the sub-heater only at the portion of the recording head where the temperature drops during ink ejection.

Japanese Unexamined Patent Publication No. 8-3233983

However, the temperature of the recording head is determined not only by the amount of heat generated by ink ejection, but also by the environmental temperature and the temperature of the heater board member itself constituting the recording head. Therefore, it is difficult to improve the accuracy of predicting the heat retention parameter of the sub-heater from the recorded data, and in the case of a recording head that requires heat retention control that suppresses temperature variation, the heat retention control based on the recorded data is not suitable.

The present invention is intended to provide the has been made in view of the prior art, temperature retaining control method capable record apparatus and a recording head executes the temperature variation is less heat keeping control at high speed in the recording head.

In order to achieve the above object, the recording device of the present invention includes the following configuration.

That is,
A heater in which a plurality of nozzle rows in which a plurality of nozzles provided with an electrothermal converter for generating heat energy for ejecting ink are arranged in a first direction are arranged in a second direction different from the first direction. A recording device that uses a recording head including a board to eject ink onto a recording medium for recording.
Regarding each of the plurality of nozzle rows arranged on the heater board, the plurality of nozzles arranged in the first direction are divided into a plurality of groups composed of a plurality of nozzles adjacent to each other, and each of the divided groups. A heater and a temperature detection sensor are provided in the vicinity of the group to form a heat retention area.
The plurality of nozzles included in each of the plurality of nozzle trains are time-division-driven.
A selection means for selecting the temperature detection sensor and
Each time the recording operation of one column is completed, the temperature information detected by the temperature detection sensor selected by the selection means is sequentially stored, and the temperature information obtained from all the heat retention areas is stored a plurality of times for each of the heat retention areas. Acquisition amount, storage means to store,
An averaging means that averages the temperature information stored in the storage means for each heat retention area, and
Using the temperature information averaged by the averaging means, the heater in the corresponding heat retention area is driven with reference to a predetermined first table showing the relationship between the temperature information and the PWM value. An acquisition means for acquiring the PWM value and
The number of nozzles driven in each of the heat retention areas is counted based on the recording signal for the time division drive, and the number of nozzles counted is used to determine the number of nozzles and the PWM value. With reference to the second table showing the relationship, the correction means for correcting the PWM value, and
It is characterized by having a drive means for driving a heater in the corresponding heat retaining area by PWM control using a PWM value acquired by the acquisition means and corrected by the correction means .

Further, when the present invention is viewed from another aspect, a plurality of nozzle rows in which a plurality of nozzles provided with an electrothermal converter that generates heat energy for ejecting ink are arranged in the first direction are arranged in the first direction. It is a heat retention control method of a recording head in a recording apparatus that discharges ink to a recording medium and records using a recording head including a heater board arranged in a second direction different from that of the heater board. With respect to each of the plurality of nozzle rows, the plurality of nozzles arranged in the first direction are divided into a plurality of groups composed of a plurality of nozzles adjacent to each other, and each of the divided groups has a heater in the vicinity of the group. And a temperature detection sensor are provided to form a heat retention area, and a plurality of nozzles included in each of the plurality of nozzle rows are driven by time division, and the selection step of selecting the temperature detection sensor and the recording operation of one column are completed. Each time, the temperature information detected by the temperature detection sensor selected in the selection step is sequentially stored in the storage means, and the temperature information obtained from all the heat retention areas is acquired a plurality of times for each of the heat retention areas. Predetermined using a storage step stored in the storage means, an averaging step of averaging the temperature information stored in the storage means for each heat retaining area, and temperature information averaged by the averaging step. The acquisition step of acquiring the PWM value for driving the heater in the corresponding heat retention area with reference to the first table showing the relationship between the temperature information and the PWM value, and the recording for the time-division drive. A second table showing a predetermined relationship between the number of nozzles and the PWM value is displayed by counting the number of nozzles driven in each of the heat insulating areas based on the signal and using the counted number of nozzles. With reference to the correction step of correcting the PWM value, and the drive step of driving the heater of the corresponding heat retention area by PWM control using the PWM value acquired by the acquisition step and corrected by the correction step. The recording head is provided with a heat retention control method .

Therefore, according to the present invention, there is an effect that high-quality printing can be realized at high speed and stably by finely controlling the temperature of the recording head.

It is an external perspective view which shows the outline of the structure of the inkjet recording apparatus which is an Example of this invention. It is a figure which shows the schematic layout of the head board of a recording head, and the internal structure of a heater board. It is a block diagram which shows the outline of the control structure of the recording apparatus shown in FIG. It is a figure explaining the heat retention control unit. It is a flowchart which shows the process of heat retention control. It is a time chart which shows the head data processing performed for a recording operation. It is a figure which shows the holding structure of a Di digital value (Di-D). It is a figure explaining the processing outline of a heat retention control unit. It is a figure explaining the processing outline of the heater board data transfer part according to another Example.

Hereinafter, examples of the present invention will be described in more detail and in detail with reference to the accompanying drawings.

In this specification, "record" (sometimes referred to as "print") is not limited to the case of forming significant information such as characters and figures, and may be significant or involuntary. It also refers to the case where an image, pattern, pattern, etc. is widely formed on a recording medium or the medium is processed, regardless of whether or not it is manifested so that it can be visually perceived by humans. ..

The term "recording medium" refers not only to paper used in general recording devices, but also to a wide range of media such as cloth, plastic film, metal plate, glass, ceramics, wood, and leather that can accept ink. Shall be.

Further, "ink" (sometimes referred to as "liquid") should be broadly interpreted as in the definition of "recording (printing)" above. Therefore, by being applied onto the recording medium, the image, pattern, pattern, etc. are formed, the recording medium is processed, or the ink is processed (for example, the colorant in the ink applied to the recording medium is solidified or insolubilized). It shall represent a liquid that can be produced.

Furthermore, "recording element (or recording element or nozzle)" is a general term for the ejection port, the liquid passage communicating with the ejection port, and the element that generates energy used for ink ejection, unless otherwise specified. To do.

The recording head substrate (head substrate) used below does not indicate a simple substrate made of a silicon semiconductor, but indicates a configuration in which each element, wiring, or the like is provided.

Further, the term “on the substrate” means not only the top of the element substrate but also the surface of the element substrate and the inside side of the element substrate in the vicinity of the surface. Further, the term "built-in" as used in the present invention does not mean that each element of a separate body is simply arranged as a separate body on the surface of a substrate, but that each element is manufactured as a semiconductor circuit. It indicates that it is integrally formed and manufactured on the element plate by a process or the like.

FIG. 1 is an external perspective view showing an outline of a configuration of a recording device that records using an inkjet recording head (hereinafter, recording head) which is a typical embodiment of the present invention.

As shown in FIG. 1, the inkjet recording device (hereinafter, recording device) 1 mounts an inkjet recording head (hereinafter, recording head) 3 for ejecting ink and recording according to an inkjet method on a carriage 2, and the carriage 2 is indicated by an arrow A. Record by reciprocating in the direction. Recording is performed by feeding a recording medium P such as a recording paper via a paper feeding mechanism 5, transporting the recording medium P to a recording position, and ejecting ink from the recording head 3 to the recording medium P at the recording position.

Not only the recording head 3 is mounted on the carriage 2 of the recording device 1, but also an ink tank 6 for storing the ink supplied to the recording head 3 is mounted. The ink tank 6 is detachable from the carriage 2.

The recording device 1 shown in FIG. 1 is capable of color recording, and for this purpose, the carriage 2 contains four inks of magenta (M), cyan (C), yellow (Y), and black (K), respectively. It is equipped with an ink cartridge. Each of these four ink cartridges can be attached and detached independently.

The recording head 3 of this embodiment employs an inkjet method that ejects ink by using heat energy. Therefore, an electric heat converter is provided. This electric heat converter is provided corresponding to each discharge port, and ink is discharged from the corresponding discharge port by applying a pulse voltage to the corresponding electric heat converter according to the recording signal.

Further, a scale 7 is provided along the moving direction of the carriage 2. The scale 7 is provided with slits at regular intervals, and an encoder (not shown) mounted on the carriage 2 reads the slits in response to the movement of the carriage 2 to generate an encoder signal. This encoder signal is a signal representing the carriage position (that is, the position of the recording head) in the moving direction of the carriage 2. The movement speed of the carriage is calculated based on the period of the encoder signal (encoder signal interval), and this encoder signal is used as a signal for timing control for ink ejection.

In this embodiment, a recording device for recording by reciprocating a carriage equipped with a recording head is used as an example, but the present invention is not limited thereto. The present invention also uses, for example, a recording device having a configuration in which a full-line recording head having a recording width equal to or longer than the width of the recording medium is used and only the recording medium is conveyed for recording. Applicable.

FIG. 2 is a diagram showing a schematic layout of a head substrate of a recording head and an internal configuration of a heater board.

As shown in FIG. 2A, four heater boards 101A to 101D are mounted on the head substrate of the recording head 3. The internal configuration of each heater board is the same, and FIG. 2B illustrates one of them, the heater board 101A. As shown in FIG. 2B, the heater board 101A is provided with a nozzle row corresponding to the four colors of ink indicated by C / M / Y / K. Each nozzle row is composed of a nozzle row of an Even row and an Odd row as shown by enlarging the portion surrounded by a broken line on the right side of FIG. 2B, and the nozzles in which the Even row and the Odd row are arranged together are arranged. Is arranged with 512 nozzles at 1200 dpi pitch intervals. Then, the ink ejection from these nozzles is executed in a time division manner.

In the embodiment shown in FIG. 2B, the number of time divisions is 4, and the time division blocks are indicated by BLK0 to 3. For convenience of explanation, in the following description, the nozzle row direction is referred to as the Y direction, and the direction orthogonal to the nozzle row is referred to as the X direction. Speaking of these directions in relation to the recording device shown in FIG. 1, the X direction is the transport direction of the recording medium (secondary scanning direction), and the X direction is the moving direction of the carriage (main scanning direction). The recording resolution is treated as 1200 dpi.

Further, as shown in FIG. 2B, the heater board 101A has four heat retaining areas 102 by evenly dividing each nozzle row into 128 nozzles. As can be seen from FIG. 2B, these 128 nozzles are continuous nozzles that are close to each other, and the plurality of nozzles that are close to each other and continuous are called a group. This means that each heater board has 16 heat insulating areas, and the entire recording head (that is, the head substrate) has 64 heat insulating areas. A diode sensor (temperature detection sensor) 103 (hereinafter, Di sensor) and a sub-heater 104 are provided for each heat retention area (that is, for each group).

Therefore, there are 64 Di-sensors 103 and 64 sub-heaters 104 in the entire recording head.

The number of heater boards mounted on the head board 100, the number of Di sensors on the head board, and the number of heat retaining areas are not limited to the above values, and may be different values.

Further, it is assumed that there is no nozzle serving as a glue margin between the four heater boards shown in FIG. 2 (a) and the nozzles are accurately bonded to the recording head at a pitch of 1200 dpi, but a certain number of nozzles are used. May be used as a glue margin for bonding.

FIG. 3 is a block diagram showing an outline of a control configuration of the recording device shown in FIG. In FIG. 3, the control configuration for moving the carriage 2 and transporting the recording medium is not described because it is known.

As shown in FIG. 3, the recording device 1 includes an encoder 201, a DRAM 202, a ROM 203, a controller 204, the above-mentioned heater boards 101A-101B, and an A / D converter 213.

Then, the controller 204 includes the discharge data generation unit 205, the CPU 206, the discharge timing generation unit 207, the Di digital value storage memory 208, the PWM value conversion table 209 of the sub-heater, the heat retention control unit 210, and the heater board data transfer units 211A to D. Be prepared. The CPU 206 reads and executes a program stored in the ROM 203, or drives a driver (not shown) of each motor or the like to control the operation of the entire recording device.

Further, the ROM 203 stores fixed data necessary for various operations of the recording device in addition to various control programs executed by the CPU 206. For example, a program that executes a recording (printing) process of a recording device is stored.

The DRAM 202 is necessary for the CPU 206 to execute a program, is used as a work area of the CPU 206, is used as a temporary storage area for various received data, and stores various setting data. In this embodiment, as will be described later, the DRAM 202 temporarily stores the output result of the discharge data generation unit 205. Although only one DRAM 202 is shown in FIG. 3, a plurality of DRAMs may be mounted. For example, the DRAM and the SRAM are mixedly mounted so as to be composed of a plurality of memories having different access speeds. It may be.

The discharge data generation unit 205 receives image data (IDATA) from a host 200 such as a personal computer (PC) or a digital camera, sorts the image data (IDATA) into discharge data (DDATA) according to the configuration of the recording head 3, and converts it into the DRAM 202. Temporarily store. Further, when the ejection data (DDATA) is generated, the dot count data (DCNT) generated by counting the ink ejection amount based on the ejection data for each dot count area in a fixed pixel unit is also stored in the DRAM 202. The pixel unit of the dot count area is determined by the processing unit of the discharge data generation unit 205, but in this embodiment, the area is 16 pixels in the X direction and 16 pixels in the Y direction.

The discharge timing generation unit 207 receives position information (ENC) from the encoder 201, which is information for determining the relative positions of the recording head 3 and the recording medium P, and discharge timing (DTMG) according to the timing set by the CPU 206. To generate. In addition, a heat retention control unit progress flag (EFLG) is also generated according to the relative position, and this is output to the CPU 206.

The four heater board data transfer units 211A to 211D read the discharge data (DDATA) from the DRAM 202 in accordance with the discharge timing (DTMG). At the same time, the head data (HDATA) is transferred to the heater boards 101A to 101D by using the Di selection information (Di-SEL) received from the heat retention control unit 210 and the PWM value information (PWM) of the sub-heater, which will be described later. As can be seen from FIG. 3, the heater board data transfer units 211A to 211D transfer the corresponding head data (HDATA) to the heater boards 101A to 101D, respectively.

The heater boards 101A to 101D eject ink from each nozzle using the ejection data included in the head data (HDATA), and A / D the Di analog value (Di-A) as the output of the Di sensor in the heater board. Output to the converter 213. When reading the Di analog value (Di-A: analog temperature information) from the heater board 101A, the heater boards 101B to D input the temperature information from each Di sensor. Further, when reading the Di analog value (Di-A) from the heater board 101B, the heater boards 101A, 101C, and 101D input the temperature information from each Di sensor. In this way, by setting only one of the heater boards 101A to 101D to the output state of the Di analog value, the input signal lines from the four heater boards 101A to 101D to the A / D converter 213 are set as one. There is. As a result, the number of signal lines on the head substrate can be reduced.

The A / D converter 213 receives the A / D conversion timing signal (ADCTMG) from the heat retention control unit 210, which will be described later, and converts the Di analog value (Di-A) into a Di digital value (Di-D: digital temperature information). Is converted to and output to the heat retention control unit 210.

The heat retention control unit 210 stores the received Di digital value (Di-D) in the Di digital value storage memory 208, and also receives the heat retention execution information (KTINFO) from the CPU 206. Then, for the heat retention area determined to require heat retention execution, the Di digital value (Di-D) stored in the Di digital value storage memory 208 is read out, and the heat retention area is used using the PWM value conversion table 209. Generates the PWM value of each sub-heater. Further, the discharge timing (DTMG) is used to generate Di selection information (Di-SEL) for selecting a diode to be externally output to each heater board for each heater board. These PWM value information (PWM) and Di selection information (Di-SEL) are output to the heater board data transfer units 211A to 211D.

In the controller 204 shown in FIG. 3, each part except the CPU 206, the Di digital value storage memory, and the PWM value conversion table 209 is composed of dedicated hardware such as an ASIC. That is, the discharge data generation unit 205, the discharge timing generation unit 207, the heat retention control unit 210, and the heater board data transfer units 211A to 211D are hardware such as an ASIC.

FIG. 4 is a diagram illustrating a heat retention control unit.

In FIG. 4, a rectangular area indicates a heat retention control unit, and the unit is 128 pixels, which is a heat retention area unit of the heater board in the Y direction, and 1024 as a unit for switching whether or not the heat retention control can be performed in the X direction. It is a pixel.

In this embodiment, as described above, since the dot count unit is 16 pixels in both the X direction and the Y direction, 64 dot count areas (= 1024/16) in the X direction and 8 dots in the Y direction (= 128). / 16) The combined unit is the heat retention control unit.

FIG. 5 is a flowchart showing the heat retention control process.

First, in step S301, the discharge data generation unit 205 receives the image data (IDATA) from the host 200. The image data (IDATA) includes image data and header information for processing the image data in the recording device.

Next, in step S302, the CPU 206 analyzes the header information included in the image data (IDATA), and executes necessary image processing on the image data according to the contents. As a result, the image data is converted into ejection data (DDATA) for ejecting ink on the heater boards 101A to 101D. Further, after conversion to ejection data (DDATA), the ink ejection amount in the ejection data is counted for each dot count area in a fixed pixel unit (16 × 16 pixels) to generate dot count data (DCNT).

Further, in step S303, the CPU 206 reads the dot count data (DCNT) from the DRAM 202 and totals the number of discharges in the heat retention control unit. Here, the aggregation in step S303 means that the number of ink ejected for each dot count area is added by the CPU 206 to calculate the number of ejected inks in the heat retention control unit. Further, the timing at which the heat retention control unit elapsed flag (EFLG) is generated from the discharge timing generation unit 207 is the timing at which 1024 pixels, which are the X-direction pixels of the heat retention control unit, have elapsed.

In step S304, it is checked whether or not the number of discharges of the heat retention control unit totaled in step S303 has reached the threshold value for executing the heat retention process for each heat retention area. In this embodiment, it is determined that the heat retention treatment is executed when the number of ink ejected is 1 or more. Here, if it is determined that the heat insulating treatment is to be executed in the heat insulating area, the process proceeds to step S305, and if it is determined that the heat insulating process is not executed, the process proceeds to step S308.

In step S305, the heat retention control unit 210 reads the Di digital value (Di-D) from the Di digital value storage memory 208, and uses the PWM value conversion table 209 to drive the sub-heater for each heater board area. To determine. Then, in step S306, the reception of the discharge timing signal (DTMG) from the discharge timing generation unit 207 is waited for, and when the discharge timing signal (DTMG) is received, the process proceeds to step S307. In step S307, the heater board data transfer units 211A to 211D receive the discharge data (DDATA) from the DRAM 202, and the Di selection information (Di-SEL) and the PWM value information (PWM) from the heat retention control unit 210. Then, these are transmitted as head data (HDATA) to the corresponding heater boards 101A to 101D. After that, the process proceeds to step S310.

On the other hand, in step S308, when the reception of the discharge timing signal (DTMG) from the discharge timing generation unit 207 is waited for and the discharge timing signal (DTMG) is received, the process proceeds to step S309. In step S309, the heater board data transfer units 211A to 211D receive the discharge data (DDATA) from the DRAM 202 and the Di selection information (Di-SEL) from the heat retention control unit 210. Then, these are transmitted as head data (HDATA) to the corresponding heater boards 101A to 101D. After that, the process proceeds to step S310.

In step S310, it is checked whether or not printing is completed, and if it is determined that printing is continuing, the process proceeds to step S311 and the heat retention control unit progress flag (EFLG) received from the discharge timing generation unit 207 is received. Find out if you are doing it. Here, if it is determined that the heat retention control unit progress flag (EFLG) has been received, the process returns to step S303, and it is determined that the heat retention control unit progress flag (EFLG) has not been received. If so, the process returns to step S304.

On the other hand, if it is determined in step S310 that printing is complete, the process is terminated.

FIG. 6 is a time chart showing the head data processing executed for the recording operation.

As shown in FIG. 6, the head data (HDATA) transferred to each of the heater boards 101A to 101D includes a latch signal (LATCH), a transfer clock (CLK), and transfer data (DATA).

First, the behavior of the latch signal (LATCH) within the rising cycle will be described.

The heater boards 101A to 101D take in transfer data (DATA) information at both rising and falling edges of the pulse of the transfer clock (CLK) each time the pulse of the latch signal (LATCH) rises. Then, ink is ejected from the nozzle to the recording medium according to the content of the information, heat is retained by the sub-heater, and temperature information of the heater board is output by the Di sensor.

As for the latch signal (LATCH), since the number of time divisions for driving the nozzles of the heater board in time division is 4 in this embodiment, the latch signal is generated four times per nozzle row. The transferred data (DATA) includes the following three pieces of information. That is,
(1) Block unit discharge data (BLK-DDATA) obtained by dividing the nozzle train by the number of time divisions of 4,
(2) Di selection information (Di-SEL) for selecting a Di sensor that outputs temperature information from four heater boards, and
(3) ON / OFF information (SUBH-ON / OFF) for the sub-heater for each heat retaining area in the heater board.

Here, the block unit ejection data (BLK-DDATA) includes ejection ON / OFF information of 128 nozzles of each color obtained by dividing 512 nozzles into four, and heat pulse information required for ejecting ink droplets from the nozzles. The Di selection information (D-SEL) is information in which the Di selection information transmitted from the heat retention control unit 210 to the four heater board data transfer units 211A to 211D is formatted so that each heater board can interpret it. In this embodiment, since the number of Di sensors in each heater board is 16, 1-bit information indicating whether or not to output the Di sensor from the heater board and which Di sensor temperature information is output are displayed. It is composed of 5 bits in total with the 4 bits of information shown.

The sub-heater ON / OFF information (SUBH-ON / OFF) converts the PWM value information (PWM) of the sub-heater transmitted from the heat retention control unit 210 to the heater board data transfer units 211A to 211D in time series for each heat retention area. It is the information that was done. For example, when Duty: 60% is input as the PWM value information (PWM) of a certain heat retention area, the PWM unit is first converted to "11111111111100000" as 20-bit information that can be controlled in 5% increments. Then, this is used one bit each time the pulse of the latch signal (LATCH) rises, and after the pulse rise of the latch signal 20 times has elapsed, it is used again from the first bit. As a result, the duty: 60% sub-heater PWM control is performed with a printing cycle of 20 latch signals, that is, 5 columns (= 20 latches / time division 4).

In this embodiment, the number of sub-heaters in each heater board is 16, so the sub-heater ON / OFF information (SUBH-ON / OFF) includes a total of 16 bits of information, one bit in each heat retaining area. ing.

After repeating the rising cycle of the pulse of the latch signal (LATCH) k times, which is the A / D conversion latch unit, the transfer operation of the transfer clock (CLK) and the transfer data (DATA) is stopped, and an AD conversion period is provided. Then, within this period, the A / D converter 213 converts the Di analog value (Di-A) into the Di digital value (Di-A) in response to the reception of the AD conversion timing signal (ADCTMG). In this embodiment, A / D conversion is performed once for each column (the number of latch signals is four times, which is the number of time divisions of the heater board). Therefore, FIG. 6 shows an example of k = 4. .. Then, the Di selection information (Di-SEL) in the head data (HDATA) transfer for these four times all have the same value.

It should be noted that the reason why the A / D conversion is executed while the transfer operation of the transfer clock (CLK) and the transfer data (DATA) is stopped is that the transfer noise due to the transfer of the head data (HDATA) is the Di analog value (Di-A). This is because it has a large effect on. Therefore, the A / D conversion may be executed at an arbitrary timing if the configuration is such that the influence of transfer noise can be sufficiently reduced.

FIG. 7 is a diagram showing a holding configuration of a Di digital value (Di-D).

In FIG. 7A, A / D conversion is sequentially output by head data transfer from 64 Di sensors existing in each heat retention area in the four heater boards, and input to the heat retention control unit 210. It shows a state in which Di digital values (Di-D) are arranged in chronological order. Further, FIG. 7B schematically shows how the Di digital value (Di-D) is stored in the Di digital value storage memory 208, and the Di digital value storage memory 208 internally has four storage areas. It is divided into 208A to 208D. The reason why the memory is divided into four areas is that when the heat retention control unit 210 uses the Di digital value (Di-D) information in order to reduce the Di sensor detection error, the moving average for the past four times is used. This is because is calculated and averaged. It should be noted that the Di digital value storage memory 208 may store information for arbitrary multiple acquisitions such as three times, five times or more, instead of the past four times.

According to FIG. 7B, the Di digital values from the area 1 to the area 64 on the (N) lap are sequentially stored in the storage area 208A. Then, the Di digital value on the (N + 1) lap goes to the storage area 208B, the Di digital value on the (N + 2) lap goes to the storage area 208C, and the Di digital value on the (N + 2) lap goes to the storage area 208D. It is stored.

When the acquired data reaches the (N + 4) lap, it is stored in the storage area 208A again. This means that the information on the (N + 4) lap overwrites the information on the (N) lap. Similarly, the temperature information is overwritten such that the (N + 5) lap is the (N + 1) lap, the (N + 6) lap is the (N + 2) lap, and so on. As a result, when it is desired to acquire the moving average of the Di digital values (Di-D), the Di digital value storage memory 208 stores the Di digital values for the past four times at that time, so that the heat retention control unit 210 The moving average of Di digital values can always be calculated using the latest information.

FIG. 8 is a diagram illustrating a processing outline of the heat retention control unit 210.

FIG. 8A is a flowchart showing the processing contents of the heat retention control unit 210, and is a detailed processing content of step S305 of the flowchart described with reference to FIG. Further, FIG. 8B is a diagram showing an example of a conversion table held by the PWM value conversion table 209.

According to FIG. 8A, first, in step S700, the Di digital values are read out one by one from the four storage areas 208A to 208D of the Di digital value storage memory 208 for each heat retention area, and the moving average is calculated for each. Calculate and generate the latest average Di digital value.

Next, in step S701, the average Di digital value is converted into the PWM value information (PWM) of the sub-heater by using the PWM value conversion table 209 for each heat retention area. In the example shown in FIG. 7B, in the PWM value conversion table 209, if the average Di digital value is in the range of 120 to 140, the PWM value information (PWM) of the subheater is converted to 60%.

Then, in step S702, the heater board data transfer units 211A to 211D are notified of the PWM value information (PWM) for each heat retaining area. After that, as described in the flowchart shown in FIG. 5, the heater board data transfer units 211A to 211D are converted into ON / OFF information (SUBH-ON / OFF) for each sub-heater for each heat retaining area in the heater board, and each heater board 1 Transferred to.

Therefore, according to the above-described embodiment, the temperature information from each Di sensor of each heater board is read as a Di digital value for each heat retention area, and the sub-heater PWM control corresponding to the temperature information is performed to realize the heat retention control. Can be done.

Further, according to the heat retention control configuration described above, the CPU does not intervene in the processing other than the heat retention execution information, and the control that generates the PWM value for driving the sub-heater from the temperature information of the Di sensor and transfers it to the heater board is inside the controller. It is implemented with the hardware of. This makes it possible to handle temperature information from a large number of Di sensors and drive control of sub-heaters at high speed, and the temperature of the recording head is controlled by finely dividing the inside of the heater board into heat retention areas and performing fine control. Heat retention control that reduces variation is realized.

<Other Examples>
In the above-described embodiment, the PWM value information of the sub-heater is determined based only on the Di digital value (Di-D). This means that the heat retention control cycle by the sub-heater cannot be set to less than the read cycle of the temperature information from the Di sensor of the heater board. This is a suitable configuration when the reading cycle of the temperature information from the Di sensor is sufficiently faster than the heat retention control cycle by the sub-heater. However, it is not suitable for a configuration in which the reading cycle of temperature information from the Di sensor is long, for example, because the A / D conversion process of the A / D converter takes time.

In this embodiment, an example in which sufficiently high-speed heat retention control is performed even in such a case will be described.

In this embodiment, it is assumed that the AD conversion latch unit shown in the head data processing shown in FIG. 6 is, for example, 40 latches, that is, k = 40. In this case, assuming that the number of time divisions of the nozzle row is 4, 40 latches correspond to 10 columns.

FIG. 9 is a diagram illustrating an outline of processing of the heater board data transfer unit according to another embodiment.

FIG. 9A shows the processing contents of the heater board data transfer units 211A to 211D, and this processing is the processing of step S307 described with reference to the flowchart of FIG. Further, FIG. 9B is a diagram showing an example of a variable PWM value conversion table.

According to FIG. 9A, first, in step S800, the heater board data transfer units 211A to 211D transmit the discharge data (DDATA) from the DRAM 202, the Di selection information (Di-SEL) and the PWM from the heat retention control unit 210. Receives value information (PWM).

Next, in step S801, the discharge data (DDATA) is divided into each heat retention area (every 128 nozzles), and the fluctuation PWM value information of the subheater is used by using the fluctuation PWM value conversion table as shown in FIG. 9B. (PWM') is generated. In the case of FIG. 9B, if the variable PWM value conversion table is used and the number of ink ejected (the number of nozzles ejecting ink) in the heat insulating area is in the range of 30 to 40, the heat insulating area is used. The number of ink ejected in the ink is converted to 10% by the fluctuation PWM value information of the sub-heater.

Next, in step S802, the variable PWM value information (PWM') is added to the PWM value information (PWM) from the heat retention control unit 210, and the PWM value information (PWM + PWM') after the addition is generated. For example, if the PWM value information (PWM) is 60% and the variable PWM value information (PWM') is 10%, the added PWM value information (PWM + PWM') is 70%.

Finally, in step S803, the sub-heater ON / OFF information (SUBH-ON / OFF) is generated from the PWM value information (PWM + PWM') after addition for each latch signal (LATCH). At the same time, block unit discharge data (BLK-DDATA) is generated from the discharge data (DDATA) and transmitted to each heater board together with Di selection information (Di-SEL).

Therefore, according to the above-described embodiment, the sub-heater control by the Di sensor is executed in the X direction in units of 10 columns to determine the PWM value with high accuracy, and in units of 1 column, the PWM value of the fluctuation based on the discharge data is determined. The PWM value can be corrected by adding. As a result, by predicting a certain temperature change from the discharge data, it is possible to realize the heat retention control by the sub-heater in a cycle shorter than the cycle of reading the temperature information from the Di sensor.

In the above-described embodiment, a single-function recording device has been described as an example, but the present invention is not limited thereto. For example, it may be a multifunction printer (copier) provided with an image reading device (scanner device) in the recording device described above, or it may be a multifunction device in which a facsimile function is added to the copying machine.

3 Recording head, 101 head board, 101A-101D heater board,
204 controller, 205, discharge data generator, 206 CPU,
207 Discharge timing generator, 210 Heat retention control unit,
211A to 211D Heater board data transfer unit, 213 A / D converter

Claims (6)

A heater in which a plurality of nozzle rows in which a plurality of nozzles provided with an electrothermal converter for generating heat energy for ejecting ink are arranged in a first direction are arranged in a second direction different from the first direction. A recording device that uses a recording head including a board to eject ink onto a recording medium for recording.
Regarding each of the plurality of nozzle rows arranged on the heater board, the plurality of nozzles arranged in the first direction are divided into a plurality of groups composed of a plurality of nozzles adjacent to each other, and each of the divided groups. A heater and a temperature detection sensor are provided in the vicinity of the group to form a heat retention area.
The plurality of nozzles included in each of the plurality of nozzle trains are time-division-driven.
A selection means for selecting the temperature detection sensor and
Each time the recording operation of one column is completed, the temperature information detected by the temperature detection sensor selected by the selection means is sequentially stored, and the temperature information obtained from all the heat retention areas is stored a plurality of times for each of the heat retention areas. Acquisition amount, storage means to store,
An averaging means that averages the temperature information stored in the storage means for each heat retention area, and
Using the temperature information averaged by the averaging means, the heater in the corresponding heat retention area is driven with reference to a predetermined first table showing the relationship between the temperature information and the PWM value. An acquisition means for acquiring the PWM value and
The number of nozzles driven in each of the heat retention areas is counted based on the recording signal for the time division drive, and the number of nozzles counted is used to determine the number of nozzles and the PWM value. With reference to the second table showing the relationship, the correction means for correcting the PWM value, and
A recording device comprising: a driving means which drives a heater of the corresponding heat-retaining area by PWM control using a PWM value acquired by the acquiring means and corrected by the modifying means . The recording device according to claim 1, further comprising a plurality of the heater boards . It has a conversion means for inputting analog temperature information detected by the temperature detection sensor for each heat retention area and converting it into digital temperature information.
The recording device according to claim 1 or 2, wherein the digital temperature information is stored in the storage means . Of claims 1 to 3, characterized by further comprising output means for outputting said recording signal for the time-division driving and selection information for selecting by the PWM value and the selection means to the heater board The recording device according to any one item . The recording device according to any one of claims 1 to 4 , wherein the temperature detection sensor is a diode. A heater in which a plurality of nozzle rows in which a plurality of nozzles provided with an electrothermal converter for generating heat energy for ejecting ink are arranged in a first direction are arranged in a second direction different from the first direction. A method for controlling heat retention of a recording head in a recording device that uses a recording head including a board to eject ink onto a recording medium for recording.
With respect to each of the plurality of nozzle rows arranged on the heater board, the plurality of nozzles arranged in the first direction are divided into a plurality of groups composed of a plurality of nozzles adjacent to each other, and each of the divided groups. A heater and a temperature detection sensor are provided in the vicinity of the group to form a heat retention area.
The plurality of nozzles included in each of the plurality of nozzle trains are time-division-driven.
The selection process for selecting the temperature detection sensor and
Each time the recording operation of one column is completed, the temperature information detected by the temperature detection sensor selected in the selection step is sequentially stored in the storage means, and the temperature information obtained from all the heat retention areas is stored in each of the heat retention areas. With respect to the storage process of storing a plurality of acquisitions in the storage means,
An averaging step of averaging the temperature information stored in the storage means for each heat retaining area, and
Using the temperature information averaged by the averaging step, referring to a predetermined first table showing the relationship between the temperature information and the PWM value, for driving the heater in the corresponding heat retention area. The acquisition process to acquire the PWM value and
The number of nozzles driven in each of the heat retention areas is counted based on the recording signal for the time division drive, and the number of nozzles counted is used to determine the number of nozzles and the PWM value. With reference to the second table showing the relationship, the correction step of correcting the PWM value and
A method for controlling heat retention of a recording head , which comprises a drive step of driving a heater in the corresponding heat retention area by PWM control using a PWM value acquired by the acquisition step and corrected by the correction step .

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