Recording device and control method

Abstract

To properly control a drive pulse of voltage to be applied while suppressing durability of a recording head.SOLUTION: A recording device includes: recording elements for discharging ink; heating elements for heating a recording head; and common wiring for applying a voltage to the recording elements and the heating elements, and determines a drive pulse to be applied to the recording elements on the basis of the simultaneous driving number of recording elements and the simultaneous driving number of heating elements.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a printing apparatus having printing elements for ejecting ink, and a control method thereof. [Background technology]

[0002] Printing devices that print images use printheads equipped with printing elements that act as heaters for ejecting ink. In addition to the printing elements, some printheads are equipped with heating elements called sub-heaters that control the ink temperature by heating or maintaining the ink temperature to ensure stable ink ejection from the printing elements. In such image printing devices, the printhead is heated to a target temperature before starting image printing, and is controlled to maintain the target temperature after image printing has begun.

[0003] However, there is a problem in that the number of simultaneously driven print elements in the print head varies depending on the image being printed, causing fluctuations in the current from the power supply of the printing device body. This causes changes in the amount of voltage drop due to the resistance of the wiring connecting the printing device body and the print head. In particular, when the voltage applied to the print head is constant, the voltage applied to the print elements also fluctuates depending on the image being printed.

[0004] Such fluctuations in the voltage applied to the printing elements result in fluctuations in the energy required to eject ink droplets, which affects the amount and speed of ink ejection, resulting in uneven density in the printed image, misaligned ink droplet landing positions, and ink droplet ejection failures.

[0005] To address this issue, Patent Document 1 describes controlling the drive pulses of the voltages applied to the printing elements when printing an image, based on the number of printing elements that are driven simultaneously. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-96470 Summary of the Invention [Problem to be solved by the invention]

[0007] On the other hand, the amount of voltage drop can change not only depending on the print element but also on the number of heating elements being driven. For example, this can occur when the wiring for applying voltage to the print element and the wiring for applying voltage to the heating element are the same. In response to this, a method can be considered in which the drive pulse is set to take into account the case in which the amount of voltage drop is greatest, i.e., when all heating elements are driven simultaneously. However, since a voltage exceeding the actual required voltage is applied to the print element, this can have the adverse effect of reducing durability.

[0008] In response to such problems, an object of the present invention is to control the driving pulse of the applied voltage while suppressing a decrease in the durability of the recording element. [Means for solving the problem]

[0009] The present invention provides a printhead comprising a plurality of printing elements for ejecting ink, a plurality of heating elements for heating the ink, and a common wiring to which the plurality of printing elements and the plurality of heating elements are commonly connected for applying a driving voltage from a driving power supply; an acquisition means for acquiring a first number of the plurality of printing elements to be driven within a predetermined time period and a second number of the plurality of heating elements to be driven within the predetermined time period; and a control means for controlling the driving of each of the plurality of printing elements and the plurality of heating elements, wherein the control means determines a driving pulse for applying a voltage to the plurality of printing elements based on the first number and the second number. [Effects of the Invention]

[0010] According to the present invention, it is possible to control the driving pulse of the applied voltage while suppressing a decrease in the durability of the recording element. [Brief explanation of the drawings]

[0011] [Figure 1] External view of the recording device [Figure 2] Schematic diagram of a recording head [Figure 3] Cross-sectional view of the recording element substrate taken along line A-A' [Figure 4] 1 is a block diagram showing an outline of the control configuration of a printing apparatus; [Figure 5] A diagram showing the power supply path of the recording device [Figure 6] Block diagram of the drive signal generation circuit [Figure 7] Flowchart showing drive pulse determination processing [Figure 8] Table showing drive pulse numbers according to head temperature [Figure 9] Table showing the basic pulse width corresponding to the head temperature and drive pulse number [Figure 10] A table showing modulation amounts corresponding to the number of simultaneously driven printing elements and heating elements. [Figure 11] A table showing the modulation amount corresponding to the number of simultaneously driven heating elements according to the ambient temperature. [Figure 12] Table showing modulation amounts corresponding to the number of simultaneously driven recording elements [Figure 13] Flowchart showing drive pulse determination processing [Figure 14] Table showing modulation amounts of drive pulses [Figure 15] Table showing target heating temperatures according to the maximum number of heating elements driven DETAILED DESCRIPTION OF THE INVENTION

[0012] (First embodiment) An embodiment of the present invention will be described below with reference to the drawings. In order to briefly explain the characteristic configuration, an outline of the device configuration, head configuration, electric elements, etc. common to each embodiment will be described.

[0013] In this specification, "recording" refers not only to the formation of meaningful information such as characters and figures, but also to the formation of images, designs, patterns, etc. on a recording medium, or the processing of a medium, regardless of whether the information is visible to humans or not.

[0014] "Recording media" refers not only to paper used in general recording devices, but also to a wide range of materials that can accept ink, such as cloth, plastic film, metal plates, glass, ceramics, wood, and leather.

[0015] "Ink" (sometimes called "liquid") should be interpreted broadly, similar to the definition of "recording" above. Therefore, it refers to a liquid that can be applied to a recording medium to form an image, design, pattern, etc., or to process the recording medium, or to process ink, such as solidifying or insolubilizing coloring materials in ink applied to the recording medium.

[0016] The term "printing element" collectively refers to elements that generate energy used to eject ink.

[0017] Unless otherwise specified, the term "nozzle" refers to a discharge port or a liquid path communicating with the discharge port.

[0018] The substrate for the printhead used in this embodiment does not simply refer to a base made of a silicon semiconductor, but refers to a configuration on which elements, wiring, etc. are provided. Furthermore, "on the substrate" does not simply refer to the top of the element substrate, but also refers to the surface of the element substrate and the inner side of the element substrate near the surface.

[0019] <Outline of the recording device> FIG. 1 is an external view of a printing apparatus according to this embodiment. The printing apparatus according to this embodiment is a so-called serial scan type inkjet printing apparatus. A carriage unit 2 carrying a print head is scanned in a main scanning direction that intersects with the transport direction of a printing medium P. During this scanning, ink is applied as a printing material to the printing medium P, thereby printing an image on the printing medium P. In the figure, the X direction is the transport direction of the printing medium P, the Y direction is the scanning direction of the carriage unit 2, and the Z direction is the vertical direction.

[0020] The configuration of the recording device and its operation during recording will be described with reference to FIG. 1. First, a recording medium P is transported from a spool 6 holding the recording medium P by a paper feed roller driven via gears by a paper feed motor 29 (not shown). Meanwhile, a carriage motor (not shown) scans a carriage unit 2 at a predetermined transport position along a guide shaft 8 extending perpendicular to the transport direction. During this scanning process, ink is ejected from the nozzles of a recording head 9 detachably attached to the carriage unit 2 at a timing based on a position signal obtained by an encoder 7. This causes an image to be recorded in an area with a bandwidth corresponding to the range in which the nozzles are arranged. In this embodiment, the carriage unit 2 scans at a scanning speed of 40 inches per second and performs an ejection operation at a recording resolution of 600 dpi (dots per inch).

[0021] Thereafter, a transport operation is performed to transport the recording medium P, and an image is recorded in an area corresponding to the next band width. In such a recording device, a transport operation corresponding to the band width may be performed between each scan, or a transport operation may not be performed for each scan, but may be performed after multiple scans of the carriage unit 2. Also, in each scan, a discharge operation is performed based on thinned data using a mask pattern for thinning out image data, and a transport operation equivalent to 1 / n of the band width is performed between scans. This method makes it possible to perform so-called multi-pass recording, in which an image is completed through n (n: a natural number equal to or greater than 2) scans and transport operations while changing the nozzles used to record in each unit area.

[0022] Printing elements for ejecting ink as droplets are arranged inside the multiple nozzles provided in the print head 9. A flexible wiring board 1 is also attached to the print head 9 for supplying signal pulses for driving the printing elements and signals for adjusting the head temperature. The other end of the flexible wiring board 1 is connected to a control circuit that controls the printing apparatus.

[0023] A carriage belt is used to transmit the driving force from the carriage motor 3 to the carriage unit 2. Instead of a carriage belt, other driving methods can be used, such as one that includes a lead screw that is rotationally driven by the carriage motor 3 and extends in the main scanning direction, and an engagement portion that is provided on the carriage unit 2 and engages with a groove in the lead screw.

[0024] The fed recording medium P is sandwiched and transported between a paper feed roller and a pinch roller, and is guided to a recording position on the platen 4. This recording position is within the area scanned by the carriage unit 2, and is a position where an image can be recorded. Normally, in a resting state, the face of the recording head 9 where the nozzles are provided is capped. Therefore, prior to recording, the cap is opened to make the recording head 9 and carriage unit 2 ready for scanning. After that, when one scan's worth of recording data has been accumulated in the buffer, the carriage motor 3 is driven to scan the carriage unit 2, and the image is recorded.

[0025] The environmental temperature and humidity sensor 5 indicated by the dashed line is placed at a position away from components that are sources of vibration or heat, such as motors and heaters, in order to reduce errors and measurement noise.

[0026] Figure 2 is a schematic diagram of the print head 9 in the printing apparatus of this embodiment. Figure 2(a) is a diagram showing the print head 9 from the direction in which ink is ejected, and Figure 2(b) is an enlarged view of the print element substrate on the left side of Figure 2(a). Figure 2(c) is a diagram showing the rear side of Figure 2(a), showing the connection part with the printing apparatus.

[0027] First, let us refer to FIG. 2(a). Two recording element substrates 10 are arranged in the recording head 9, and multiple recording element arrays are arranged on them along the main scanning direction in the figure. Recording element array 11 is a recording element array for ejecting black (Bk) ink. Similarly, recording element array 12 is a recording element array for ejecting gray (Gy), recording element array 13 is a recording element array for ejecting light gray (Lgy), recording element array 14 is a recording element array for ejecting light cyan (Lc), recording element array 15 is a recording element array for ejecting cyan (C), recording element array 16 is a recording element array for ejecting light magenta (Lm), recording element array 17 is a recording element array for ejecting magenta (M), and recording element array 18 is a recording element array for ejecting yellow (Y) ink. Ink is supplied to each recording element array from a common ink liquid chamber 26 via ink flow paths inside the recording head 9.

[0028] Please refer to FIG. 2(b). This figure is an enlarged view of two recording element substrates 10 arranged side by side in the recording head 9. In the recording head 9 of this embodiment, the recording element arrays 11 to 18 are each formed of two rows of recording elements. The recording elements in each row are arranged at intervals of 600 dpi, and in the X direction of the figure, the recording elements in one row are shifted by 1200 dpi relative to the recording elements in the other row. 768 recording elements are arranged in each row in the X direction, for a total of 1536 recording elements.

[0029] Temperature sensors S1 to S10, each made of a diode, are arranged on the recording element substrate 10. Temperature sensors S6, S7, S8, and S9 for detecting the temperature of the recording element substrate 10 are arranged at the ends in the X direction. The temperature sensors S6 to S9 are located approximately 0.2 mm away from the endmost recording elements of the recording element array in the sub-scanning direction, and are located at the midpoint between the two recording element arrays in the main scanning direction. Temperature sensors S1, S2, S3, S4, and S5 for detecting the temperature of the central portion are arranged in the center of the recording element array. These temperature sensors S1 to S5 are also arranged in the center position of the recording element array.

[0030] The heaters 19 and 20 are arranged to surround the recording element substrate 10, positioned 1.2 mm outward from the endmost recording elements in the main scanning direction and 0.2 mm outward from the temperature sensor in the sub-scanning direction. The size of the recording element substrate 10 is 9.55 mm wide x 39.0 mm long.

[0031] See FIG. 2(c). The print head 9 is electrically connected to the main body of the printing apparatus via contact pads 21 and flexible printed circuit board wiring. This allows for the supply of electrical signals for controlling ink ejection and heat retention, as well as power consumed by the print head 9. When connecting, a pin-like receiving mechanism is provided on the main body side for fixing, and the print head 9 is pressed and fixed to the main body of the printing apparatus, thereby ensuring a stable connection. In the print head 9 of this embodiment, a common power supply is used for ejection and heat retention, and common wiring is used for applying a drive voltage. Sharing the connection wiring and reducing the number of terminals has the advantage of simplifying the circuit.

[0032] FIG. 3 is a cross-sectional view of the recording element substrate 10 taken along line AA′ in FIG. 2(b). The recording head 9 of this embodiment is a so-called thermal inkjet recording head that ejects ink by generating thermal energy when a driving voltage is applied. The figure shows a support substrate 27, recording elements 22, which are electrothermal conversion elements, and ejection ports 23 (nozzles). Ink flow paths 25 are formed between the support substrate 27 and an orifice plate 28, and partitions (not shown) are provided between the multiple ink flow paths 25. The recording elements 22 are provided on the support substrate 27 so as to face the ejection ports 23, and a protective film or the like is formed on their surfaces. Ink is supplied from a common liquid chamber 26 located at the bottom in this figure to each flow path 25 located above. When a driving voltage is applied to the recording elements 22, ink is ejected as droplets from the ejection ports.

[0033] Furthermore, temperature adjustment control is performed to maintain a constant viscosity of the ink inside the print head 9 regardless of the environmental temperature. This temperature adjustment control is performed by the heating elements 30 provided on the print element substrate 10.

[0034] 4, which will be described later, is disposed in the printhead 9. The head driver 111 is connected to each of the print elements 22 and the heating elements 30, and can control the ON / OFF of the drive currents of the print elements 22 and the heating elements 30.

[0035] Figure 4 is a block diagram showing the control configuration of the printing apparatus. A programmable peripheral interface (PPI) 101 receives printing information signals, including command signals and printing data, sent from a host computer 100 and transfers them to an MPU 102. It also sends status information about the printing apparatus to the host computer 100 as needed. Input and output is performed between the PPI and a console 106, which has a setting input unit that allows the user to make various settings and a display unit that displays messages to the user. It also receives signal inputs from a group of sensors 107, which includes a home position sensor that detects when the carriage unit 2 is in the home position and a capping sensor.

[0036] An MPU (microprocessing unit) 102 controls each component of the printing apparatus in accordance with a control program stored in a control ROM 105. A RAM 103 stores received signals and is also used as a work area for the MPU 102, temporarily storing various data. A print buffer 121 stores print data expanded in the RAM 103 or the like and has a capacity for multiple lines. In addition to the control program, the control ROM 105 can store data used in the control process described below, such as fixed data corresponding to data for determining the combination of temperature sensors related to the main components of this embodiment. Each of these components is controlled by the MPU 102 via an address bus 117 and a data bus 118.

[0037] Motor drivers 114, 115, and 116 are drivers for driving the capping motor 113, the carriage motor 3, and the paper feed motor 29 under the control of the MPU 102, respectively.

[0038] The sheet sensor 109 is a sensor for detecting the presence or absence of a recording medium, and detects whether the recording medium has been supplied to a position where it can be printed by the printhead 9. The head driver 111 is a driver for driving the printing elements 22 of the printhead 9 in response to a print signal. The humidity sensor 122 detects the environmental temperature and humidity in the installation environment of the printing apparatus main body. The power supply unit 120 supplies power to each of the above units and has an AC adapter and a battery as a drive power supply device.

[0039] A recording system consisting of a host computer 100 supplies a recording signal to a recording device. When the host computer 100 transmits recording data via a parallel port, an infrared port, or a network, a predetermined command is added to the beginning of the data. For example, the command may include the type of recording medium (plain paper, glossy paper, coated paper, transfer film, cardboard, banner paper, etc.), the medium size (A0, A1, B0, B1, etc.), the recording quality (draft, high quality, medium quality, emphasis on a specific color, monochrome / color, etc.), and whether or not to automatically detect objects. Furthermore, if a treatment liquid is to be applied to improve the fixation of ink on the recording medium, information specifying whether or not to apply the treatment liquid is also transmitted as a command.

[0040] In accordance with these commands, data necessary for printing is read from ROM 105, and printing operations are performed based on this data. For example, this data is data for determining the number of printing passes when performing the above-mentioned multi-pass printing, the amount of ink applied per unit area of ​​the printing medium, the printing direction, etc. It may also be data such as the type of mask used for thinning out data when performing multi-pass printing, drive conditions based on the temperature sensor detection value of the print head 9 (for example, the shape of the drive pulse to be applied, the application time, etc.), dot size, transport conditions, number of ink colors, carriage speed, etc.

[0041] 5 is a diagram showing the power supply paths of the printing apparatus of this embodiment. In the print head 9, the multiple printing elements 22 and the multiple heating elements 30 are connected by common wiring on the printing element substrate 10. In this embodiment, these elements are commonly connected by so-called solid wiring.

[0042] When a pulsed current is supplied to the recording elements 22 and the heating elements 30, it is smoothed by the electrolytic capacitors 501 on the CR board 500. Therefore, the current driving the printhead 9 experiences a voltage drop due to the wiring resistance along the way. The current acts as a pulsed current from the CR board 500 to the printhead 9, and as a smoothed current from the CR board 500 to the main power supply 120, resulting in a voltage drop along the way. Because the recording elements 22 and the heating elements 30 share a common wiring configuration, the greater the number of driven elements, the greater the voltage drop. Furthermore, voltage fluctuations occur depending on the number of elements simultaneously driven. This voltage fluctuation poses a problem of instability in ink droplet ejection from the recording elements 22. Therefore, in this embodiment, the number of simultaneously driven recording elements 22 and heating elements 30 is determined, and the voltage drive pulse applied to the recording elements 22 is set according to the number of simultaneously driven elements. This enables a consistent energy supply regardless of the number of simultaneously driven elements.

[0043] 6 is a block diagram of the drive signal generation circuit of this embodiment. Using this diagram, a method for determining the number of recording elements 22 and heating elements 30 to be simultaneously driven will be described.

[0044] One block period is used as the time reference for the determination process, print data is transferred, and in the next period, the nozzles corresponding to the transferred print data are driven. In this diagram, the explanation will be given using the synchronous trigger as the reference.

[0045] When a synchronization trigger is received, the print data to be transferred is fetched from the print buffer and latched in the print data latch 602, and the block switching unit 600 switches the block signal. Then, the clock generation unit 601 generates a clock HCLK signal for transferring the latched print data to the print head. At this time, the number of print data bits in one latch (i.e., the number of print elements 22 driven within a specified time) and the number of heating element bits driven within a specified time for print head temperature control are acquired. This acquisition operation is performed every time between latches.

[0046] In this embodiment, the number of elements driven simultaneously refers to the number driven during the latch interval of the recording element 22 and the heating element 30, but the latch timing of the recording element 22 and the latch timing of the heating element 30 do not have to be simultaneous. The latch interval of the heating element 30 may be slow, in which case the number of bits at the time of the heating element 30's previous latch is read and counted for each latch interval of the recording element 22. This addition method is easy if there is sufficient time in the block period, by enabling the recording data and incrementing the counter with the HCLK signal, but if there is not enough time, it is also possible to add all the bits in an adder and complete determination of the number of elements driven simultaneously while the recording data is being transferred.

[0047] The heat pulse signal HE is output with its pulse width modulated from the pulse generating unit 605. As an example of a method for modulating the pulse width, a drive pulse width table shown in Fig. 9 (described later) is stored in the RAM 103, and the required modulation amount is read from the drive pulse width table using the number of simultaneous drives as an address, and used for modulating the pulse width.

[0048] FIG. 7 is a flowchart showing the drive pulse determination process performed in this embodiment. In step S701, a print signal for printing an image is received. In step S702, temperature adjustment control is initiated. The temperature adjustment control in this embodiment is control for driving the heating element 30 to raise the temperature of the print head to a temperature at which printing can begin before printing begins. In step S703, the heater rank and head temperature for the print head are detected. The heater rank is information corresponding to the difference in resistance value between individual heater boards in the print head, and if this heater rank differs, the pulse width required to eject ink droplets from the nozzle will differ.

[0049] In step S704, the table in Fig. 8 is referenced to determine a drive pulse number indicating the length of the basic pulse to be applied based on the detected head temperature. In step S705, the table in Fig. 9 is referenced to determine the width of the basic pulse corresponding to the detected head temperature and the determined drive pulse number.

[0050] In step S706, the number of simultaneously driven printing elements 22 and heating elements 30 of the printhead to be processed, as described above with reference to Figure 6, is individually obtained. In step S707, the table in Figure 10(a) is referenced to determine the modulation amount for modulating the width of the basic pulse corresponding to the obtained number of simultaneously driven printing elements 22. In step S708, the table in Figure 10(b) is referenced to determine the modulation amount for modulating the width of the basic pulse corresponding to the obtained number of simultaneously driven heating elements 30.

[0051] In step S709, the modulation amount corresponding to the number of simultaneously driven print elements determined in step S707 and the modulation amount corresponding to the number of simultaneously driven heating elements determined in step S708 are added to the basic pulse width determined in step S705, thereby determining the modulated drive pulse.

[0052] As described above, the final drive pulse is determined by modulating the basic pulse width, which is determined based on drive conditions such as printhead characteristics and head temperature, with a modulation amount corresponding to the number of simultaneously driven print elements 22 and the number of simultaneously driven heating elements 30. This configuration makes it possible to appropriately control the pulse width to compensate for voltage drops caused by an increase in the number of simultaneously driven print elements. Furthermore, by controlling the drive pulse based on the number of simultaneously driven print elements, it is possible to prevent density unevenness and landing errors in the printed image, and also to suppress a decrease in the durability of the print elements 22.

[0053] (Second embodiment) In the first embodiment, the drive pulses were determined based on the number of simultaneously driven recording elements 22 and the number of simultaneously driven heating elements 30. In this embodiment, in consideration of differences in voltage drop amounts depending on the type of element, the modulation amount is weighted based on a modulation amount table corresponding to the number of driven recording elements 22 and a modulation amount table corresponding to the number of driven heating elements 30, in order to perform more appropriate pulse correction control.

[0054] In a low-temperature environment, even if the temperature adjustment control in step S702 is performed, there is a problem that the print head 9 does not warm up easily. To address this, the modulation amount corresponding to the number of driven heating elements 30 is weighted according to the environmental temperature.

[0055] FIG. 11 is a table for determining the modulation amount for modulating the width of a basic pulse corresponding to the number of simultaneously driven heating elements 30 in this embodiment. By using the table in this figure instead of the table in FIG. 10(b) in the first embodiment, it is possible to maintain constant ejection performance. The ambient temperature is acquired by a temperature and humidity sensor provided in the main body of the recording apparatus. The configuration other than this table is the same as in the first embodiment.

[0056] 12 is an example of a table of modulation amounts corresponding to the number of simultaneously driven recording elements 22. Because the voltage drop increases as the distance from the contact pad 21 increases, the modulation amount corresponding to the number of simultaneously driven recording elements 22 is further weighted depending on the position of the recording element array. As shown in FIG. 2(b), on the recording element substrate 10, recording element array 11, recording element array 12, and recording element array 13 are arranged in this order from left to right in the Y direction of the figure. That is, the recording element arrays are arranged in order from the shortest distance from the contact pad 21 to the shortest distance, and the range of the modulation amount corresponding to the number of drives is increased for recording elements included in recording element arrays that are farther away from the contact pad.

[0057] As described above, according to this embodiment, it is possible to perform more accurate pulse correction control based on the characteristics of the elements, the ambient temperature of the printing apparatus, and the configuration of the printing element substrate.

[0058] (Third embodiment) Next, a third embodiment will be described. As described above, extending the pulse width is effective in suppressing image defects caused by voltage fluctuations applied to the recording elements of the recording head 9. However, the specifications of the recording element substrate generally limit the length of the pulse width that can be input. For this reason, in a low-temperature environment, the energy applied to the recording elements 22 may be insufficient. Furthermore, even when the drive frequency is high, the maximum pulse width that can be input is shortened, so the energy applied to the recording elements 22 may be insufficient.

[0059] In contrast, in this embodiment, the maximum number of heating elements 30 that can be driven is set and limited depending on the environmental temperature and the print mode, thereby increasing the target heating temperature of the print head 9 and compensating for the energy loss.

[0060] FIG. 13 is a flowchart of the process executed in this embodiment. Descriptions of documents similar to those in the first embodiment will be omitted. In step S1402, ambient temperature and print mode information are acquired. In step S1403, the tables in FIGS. 14A and 14B are referenced to determine whether the conditions for limiting the maximum number of driven heating elements 30 are met. FIG. 15A shows the conditions for determining whether the maximum number of driven heating elements 30 is limited by the ambient temperature, and the maximum number of driven heating elements 30 when it is determined that a limit exists, i.e., that a limit is necessary. If the ambient temperature meets the conditions for limiting the maximum number of driven heating elements 30, i.e., if it is lower than a predetermined ambient temperature (20 degrees in this figure), the maximum number of driven heating elements 30 is set in step S1404. FIG. 15B shows the conditions for determining whether the maximum number of driven heating elements 30 is limited by the print mode, and the maximum number of driven heating elements 30 when it is determined that a limit exists. If the print mode is determined to require a reduction in the number of driven heating elements 30, the maximum number of driven heating elements 30 is set in step S1404. Next, in step S1405, the heating target temperature is finally determined by referring to the table in Fig. 15, and then the process returns to step S1406 and the same process as in embodiment 1 is performed. In step S1403, if the condition for limiting the maximum number of driven heating elements 30 is not met, the process proceeds to step S1405 and the same process as in embodiment 1 is performed.

[0061] As described above, according to this embodiment, the number of driven heating elements 30 is limited based on the ambient temperature. As a result, the modulation amount based on the maximum number of simultaneously driven heating elements 30 is limited among the modulation amounts added to the basic pulse, and modulation amounts due to other conditions can be guaranteed.

[0062] (Other embodiments) In the above embodiment, the modulation amount corresponding to the number of simultaneously driven print elements and the modulation amount corresponding to the number of simultaneously driven heating elements are calculated separately and added to the basic pulse, but it is also possible to calculate one modulation amount at a time. For example, the modulation amount may be calculated by calculating the sum of the number of simultaneously driven print elements and the number of simultaneously driven heating elements, or by multiplying at least one of them by a coefficient to give a weight, and then calculating the modulation amount based on this sum.

[0063] In the above embodiment, an example has been described in which the present invention is used in a printing apparatus equipped with a so-called serial type print head, in which the carriage unit 2 carrying the print head 9 scans in a direction intersecting the direction in which the print medium is transported. However, the present invention is not limited to this, and can also be applied to a printing apparatus equipped with a so-called line head, in which the print medium is transported in a direction intersecting the direction in which the print elements are arranged. [Explanation of symbols]

[0064] 9. Recording head 10. Recording element board 22 Recording element 30 heating element 120 Power supply section 500 CR base 605 Pulse Generation Unit

Claims

1. a print head including a plurality of print elements for ejecting ink, a plurality of heating elements for heating the ink, and common wiring to which the plurality of print elements and the plurality of heating elements are commonly connected for applying a drive voltage from a drive power supply; an acquiring unit that acquires a first number of the plurality of printing elements that are driven within a predetermined time period and a second number of the plurality of heating elements that are driven within the predetermined time period; a control unit for controlling the driving of each of the plurality of recording elements and the plurality of heating elements; Equipped with The recording apparatus is characterized in that the control means determines drive pulses for applying voltages to the plurality of recording elements based on the first number and the second number.

2. 2. The recording apparatus according to claim 1, wherein the control means determines the drive pulse by adding a modulation amount based on the first number and the second number to a basic pulse.

3. The recording device described in claim 1 or 2, characterized in that the control means obtains a first modulation amount based on the first number, obtains a second modulation amount based on the second number, and determines the drive pulse by adding the first modulation amount and the second modulation amount to a basic pulse.

4. the acquiring means acquires the first number and the second number at each predetermined time; 4. The recording apparatus according to claim 1, wherein the control means determines the drive pulse for each predetermined time.

5. 5. The recording apparatus according to claim 1, wherein the acquisition unit acquires the first number and the second number at a timing when recording data is latched.

6. 4. The recording apparatus according to claim 3, wherein the first modulation amount is set to be longer when the first number is a predetermined number than when the first number is smaller than the predetermined number.

7. 4. The recording apparatus according to claim 3, wherein the second modulation amount is set to be longer when the second number is a predetermined number than when the second number is smaller than the predetermined number.

8. 4. The recording apparatus according to claim 3, wherein the second modulation amount is acquired based on the second number and an environmental temperature.

9. 4. The printing apparatus according to claim 2, wherein the control means acquires the basic pulse based on at least one of a heater rank of each individual print head and a head temperature detected by a temperature sensor.

10. 10. The recording apparatus according to claim 1, wherein the control means determines the second maximum number of driving operations based on at least one of an environmental temperature and a recording mode.

11. a print head including a plurality of print elements for ejecting ink, a plurality of heating elements for heating the ink, and common wiring to which the plurality of print elements and the plurality of heating elements are commonly connected for applying a drive voltage from a drive power supply; a control unit for controlling the driving of each of the plurality of recording elements and the plurality of heating elements; A control method for a recording device comprising: obtaining a first number of the plurality of printing elements that are driven within a predetermined time period and a second number of the plurality of heating elements that are driven within the predetermined time period; A control method comprising determining a drive pulse for applying a voltage to the plurality of recording elements based on the first number and the second number.

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