Recording device

Abstract

To improve the accuracy of inspections regarding faulty recording head connections. [Solution] A recording device comprising a recording head having a recording element and a transmitting means that transmits a data signal and a clock signal by differential transmission via a plurality of signal lines, wherein the recording head includes a receiving means that receives the clock signal and the data signal, and the data signal includes a first data sequence transmitted when the clock signal is in a first period and a second data sequence transmitted when the clock signal is in a second period that is longer than the first period.

Description

Technical Field

[0001] The present invention relates to a recording apparatus.

Background Art

[0002] There is known a recording apparatus that ejects ink onto a recording medium to record an image. In a recording apparatus in which a recording head for ejecting ink is detachable, poor contact may occur in the electrical contacts between the recording head and the recording apparatus (apparatus main body) when the recording head is attached. Poor contact occurs, for example, when minute dust is sandwiched between the contacts on the recording head side and the contacts on the recording apparatus side. When there is poor contact, control data for driving a recording element transmitted from the recording apparatus to the recording head is not properly received. Therefore, a recording apparatus provided with an inspection function for connection failure has been proposed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For data transmission of control data transmitted from a recording apparatus to a recording head, high-frequency data transmission is performed to improve the recording speed. For example, a differential signal (LVDS) method advantageous for high speed is used. Along with the increase in the frequency of the signal, when inspecting for poor contact of the contacts on the signal line for data transmission, an erroneous determination may occur due to the influence of the time constant caused by the built-in circuit of the recording head.

[0005] The present invention provides a technique capable of improving the inspection accuracy regarding connection failure of a recording head.

Means for Solving the Problems

[0006] According to the present invention, A recording head having a recording element, A recording device comprising a transmitting means that transmits data signals and clock signals by differential transmission method via multiple signal lines, The recording head includes receiving means for receiving the clock signal and the data signal, A recording device is provided, characterized in that the data signal includes a first data sequence transmitted when the clock signal is in a first period, and a second data sequence transmitted when the clock signal is in a second period that is longer than the first period. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technology that can improve the accuracy of inspections related to faulty recording head connections. [Brief explanation of the drawing]

[0008] [Figure 1] (a) and (b) are external perspective views of a recording system according to one embodiment of the present invention. [Figure 2] Block diagrams of the control system of the recording system shown in Figures 1(a) and 1(b). [Figure 3] (a) is a diagram illustrating the signal lines between the LVDS transmitting circuit and the LVDS receiving circuit, and (b) is a diagram illustrating an example of faulty signal line wiring. [Figure 4] (a) is an explanatory diagram of the trigger signal, (b) is a diagram showing an example of the configuration of the signal sequence for recording control data, (c) is a diagram showing an example of the configuration of the signal sequence for connection confirmation data, (d) is a diagram showing an example of information indicating the connection judgment result (normal), and (e) is a diagram showing an example of information indicating the connection judgment result (fail). [Figure 5] A timing chart showing an example signal based on the period (frequency) during the transmission of recording control data. [Figure 6] A timing chart showing an example signal based on a period (frequency) that takes time constants into account. [Figure 7] (a) and (b) are flowcharts showing examples of processing by the control unit of the recording device. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention to the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, the same or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] <First Embodiment> <Overview of the recording system> Figure 1(a) is an external perspective view of a recording system according to one embodiment of the present invention, and Figure 1(b) is a perspective view of the recording system with the upper cover removed. The recording system of this embodiment comprises a recording device 2 and a recording head 11. The recording system may also be called a recording device, in which case the recording device 2 may also be called the device body.

[0011] Recording device 2 is an inkjet printer, and in this embodiment, a recording device that uses relatively large size recording media (so-called large format size) such as A0 size or B0 size is assumed. However, the present invention is also applicable to recording devices that use relatively small size recording media, and to other types of recording devices.

[0012] Furthermore, "recording" includes not only cases where meaningful information such as characters and figures is formed, but also broadly cases where images, patterns, etc. are formed on a recording medium, or where the medium is processed, regardless of whether it is meaningful or not, and does not depend on whether or not it is manifested in a way that can be perceived visually by humans.In addition, in this embodiment, a sheet of paper is assumed as the "recording medium," but it may also be cloth, plastic film, etc.

[0013] As shown in FIG. 1(a), an insertion slot 88 is provided in the front surface of the recording apparatus 2, and a roll paper cassette 89 that can be opened and closed toward the front is provided below the insertion slot 88. The recording medium (sheet) is supplied from the insertion slot 88 or the roll paper cassette 89 into the recording apparatus 2.

[0014] The recording apparatus 2 includes a housing 94 supported by two legs 93, a stacker 90 for stacking the discharged recording media, and a transparent and openable / closable upper cover 91 through which the interior can be seen. Further, an operation unit 420 and an ink tank 8 are disposed on the right side of the housing 94.

[0015] As shown in FIG. 1(b), the recording apparatus 2 includes a conveyance roller 70 for conveying the recording medium in the direction of arrow B (sub-scanning direction), and a carriage 4 supported so as to be reciprocally movable in the width direction of the recording medium (direction of arrow A, main scanning direction). The conveyance roller 80 constitutes a conveyance mechanism together with a motor and a speed reduction mechanism (not shown), and conveys the recording medium by the rotation of the conveyance roller 80.

[0016] The carriage 4 is connected to an endless carriage belt 270. The carriage belt 270 constitutes a belt transmission mechanism together with a carriage motor and pulleys (not shown), and the carriage 4 moves by the running of the carriage belt 270. The position of the carriage 4 is detected by a sensor (not shown). A plurality of recording heads 11 and a sensor unit 30 are provided on the carriage 4.

[0017] In this embodiment, color recording can be performed on a recording medium. For this reason, a recording head (hereinafter referred to as the recording head) 11 composed of four heads corresponding to the types of ink is mounted on the carriage 4. That is, the recording head 11 is composed of, for example, a K head that discharges K (black) ink, a C head that discharges C (cyan) ink, an M head that discharges M (magenta) ink, and a Y head that discharges Y (yellow) ink. The ink is supplied from the ink tank 8. The recovery unit 9 sucks, for example, the ink ejection port of the recording head 11 and eliminates poor ink ejection due to clogging of the ejection port or the like. The recording head 11 may be a unit for each type of ink, or may be a single unit provided with heads for a plurality of types of ink.

[0018] In the case of this embodiment, the recording head 11 is detachable from the carriage 4. When the performance of the recording head 11 deteriorates, the recording head 11 can be replaced. That is, the old recording head 11 can be removed from the carriage 4, and a new recording head 11 can be mounted on the carriage 4.

[0019] The sensor unit 30 is a unit capable of reading an image recorded on a recording medium. The sensor unit 30 is, for example, a reflection type optical sensor, and reads an image by detecting the density of an image (for example, a pattern) formed on the recording medium. By combining the conveyance of the recording medium in the sub-scanning direction and the movement of the carriage 4 in the main scanning direction, the sensor unit 30 can read an image at an arbitrary position on the recording medium. The sensor unit 30 can also be used for detecting the end of the recording medium and discriminating the type of the recording medium.

[0020] When recording an image on a recording medium with the above configuration, the conveyance roller 70 conveys the recording medium to a predetermined recording start position. Thereafter, by repeating the operation of discharging ink while scanning the recording head 11 in the main scanning direction by the carriage 4 and the operation of conveying the recording medium in the sub-scanning direction by the conveyance roller 70, recording of an image on the entire recording medium is performed.

[0021] Specifically, the carriage 4 moves in the direction of arrow A shown in Figure 1(b) by the belt 270 and carriage motor (not shown), thereby recording onto the recording medium. When the carriage 4 is returned to its position before scanning (home position), the transport roller 80 transports the recording medium in the sub-scanning direction (direction of arrow B shown in Figure 1(b)), and then the carriage 4 is scanned again in the direction of arrow A in Figure 1. In this way, images, characters, etc., are recorded onto the recording medium. The above operation is repeated until recording on one recording medium is complete, at which point the recording medium is ejected into the stacker 90, and recording on one medium is complete. Thus, the recording device 2 of this embodiment is a serial inkjet printer that performs recording by scanning the recording head 11, but the present invention is also applicable to recording devices with a full line head.

[0022] <Control system configuration> Figure 2 is a block diagram of the control system of the recording system in this embodiment. The recording device 2 is equipped with a control unit 100, and the recording head 11 has a built-in head circuit 200.

[0023] The control unit 100 has the following configuration. The CPU 101 controls the entire recording device 2. The CPU 101 controls the operation of the entire recording device 2 by executing the operation control program stored in the ROM 106. The operation unit 420 is, for example, a touch panel, and the CPU 101 detects its input and controls its display.

[0024] The host interface 103 connects the recording device 2 and the host computer 300, and enables data transmission and reception between them. Recording job data received from the host computer 300 via the host interface 103 is stored in the RAM 108. The host interface 103 communicates using, for example, a serial communication method such as USB or a network communication method such as 1000Base-TX.

[0025] RAM108 is connected to the system bus via a RAM controller 109, which is responsible for its access control. RAM108 functions as work memory when executing operation control programs run on the CPU 101. RAM108 also functions as buffer memory for storing recording job data and various intermediate data generated during the recording process.

[0026] ROM 106 is connected to the system bus via a ROM controller that manages its access control. ROM 106 is a memory that stores operation control programs executed by the CPU 101, various data for recording control, and various screen data for display on the operation unit 420. The operation control programs include a control program for the printer engine 208 and a connection test program. The connection test program determines whether the recording head 11 is properly mounted to the recording device 2, and an example of its processing will be described later.

[0027] The HDD104 functions as a high-capacity storage device for the recording device 2 and can be used, for example, to store recording job data received from the host computer 300.

[0028] The image processing circuit 102 converts the recording job data received from the host computer 300 into image data for output to the recording medium and stores it in the RAM 108. For example, it performs color space conversion processing, gamma correction processing, and quantization processing using error diffusion on the image data transmitted from the host computer 300 as recording job data.

[0029] The printer engine 110 includes various actuators and sensors for the recording device 2, such as motors that drive the transport rollers 80 and motors that move the carriage 4. The printer engine 110 is connected to the system bus via an interface 111, and its operation is controlled by the CPU 101.

[0030] The recording control data generation circuit 112 generates recording control data to cause the recording head 11 to perform ink ejection. The recording control data generation circuit 112 reads image data from RAM 108 according to an ejection timing signal generated from a signal indicating the position of carriage 4. Then, it performs data processing according to the various drive modes of the nozzles of the recording head 11 to generate recording control data. The generated recording control data may be temporarily stored in RAM 108. The recording control data is converted into a serial signal and transmitted to the recording head 11 from LVDS transmission circuit 113. Heat data based on the divided pulse width modulation drive method may be transmitted along with the recording control data. The divided pulse width modulation drive method is a method in which, for example, the pulse applied to the recording element (heater) is not a single pulse, but consists of a pre-pulse that preheats the ink directly above the heater and a main pulse that foams the ink.

[0031] The LVDS transmission circuit 113 (transmission means) is a differential transmission signal transmission circuit that transmits differential transmission signals. The connection confirmation data generation circuit 114 generates connection confirmation data to confirm the connection of the recording head 11 to the recording device 2. The connection confirmation data is converted into a serial signal and transmitted from the LVDS transmission circuit 113 to the recording head 11.

[0032] The head circuit 200 has the following configuration. Communication between the control unit 100 and the head circuit 200 is performed using a differential transmission method with LVDS signal lines 115 between the LVDS transmission circuit 113 and the LVDS reception circuit 202. Data is transmitted and received in a single-ended format through other communication paths.

[0033] The LVDS receiving circuit 202 (receiving means) receives the signal sequence of the recording control data transmitted from the LVDS transmitting circuit 113, deserializes it, and outputs it to the control circuit 201. The control circuit 201 controls the driving circuit 204 based on the recording control data and drives the recording element 205. The recording element 205 is provided for each ink ejection port and is an element that ejects ink by supplying power, and in particular, is an electrothermal conversion element (heater). The electrothermal conversion element heats up by being energized to foam the ink, and ejects the ink from the ink ejection port with the foaming energy. Note that as the recording element 205, other recording elements such as a piezo element may be used instead of the electrothermal conversion element.

[0034] The reception result transmission circuit 203 is an information transmission circuit that transmits information related to the reception result of the signal sequence by the LVDS receiving circuit 202 to the control unit 100. More specifically, the reception result transmission circuit 203 is a signal sequence determination circuit that monitors the signal sequence received by the LVDS receiving circuit 202 and transmits information indicating whether there is an error in the signal sequence to the control unit 100.

[0035] The memory 206 is a non-volatile memory that stores the individual information of the recording head 11 and the like, and for example, is a ROM. The memory 206 is connected to the control unit 100 via a memory controller that controls its access, and the CPU 101 can acquire the information stored in the memory 206.

[0036] <LVDS signal line> Figure 3(a) is an explanatory diagram of the LVDS signal line 115. The LVDS signal line 115 includes a signal line for the CLK+ signal, a signal line for the CLK- signal, a signal line for the DATA+ signal, and a signal line for the DATA- signal. The CLK+ signal and the CLK- signal are clock signals with their positive and negative polarities inverted from each other. The DATA+ signal and the DATA- signal are data signals with their positive and negative polarities inverted from each other. Contacts C1 to C4 exist on each signal line. When the recording head 11 is mounted on the carriage 4, each signal line is electrically connected at contacts C1 to C4. A terminating resistor 202a is connected between the signal line for the CLK+ signal and the signal line for the CLK- signal. Also, a terminating resistor 202b is connected between the signal line for the DATA+ signal and the signal line for the DATA- signal. The resistance values ​​of the terminating resistors 202a and 202b are, for example, 100Ω.

[0037] <Checking for connection problems> If foreign matter gets caught in contacts C1 to C4, causing a contact failure, it will interfere with data transmission from the control unit 100 to the recording head 11. For example, this occurs when the electrical connection at contact C4 is interrupted, as shown in Figure 3(b). The following describes the inspection of connection failures of the recording head 11 to the recording device 2.

[0038] Figures 4(a) to 4(e) are explanatory diagrams of the operation of the reception result transmission circuit 203. Figure 4(a) shows an example of a trigger signal transmitted from the LVDS transmission circuit 113. The time between trigger signal 21 and the next trigger signal 22 is one unit of the determination period.

[0039] Figure 4(b) shows the signal array structure (data format) of the recording control data. The recording control data consists of a start command 23 (first signal sequence), multiple recording data 24 (second signal sequence), and a CRC command 25 signal sequence. The start command 23 is a signal sequence indicating the start of transmission, and the recording data 24 is a signal sequence corresponding to the actual control data of the recording element 205. Figure 4(c) shows the signal array structure of the connection confirmation data. In this embodiment, the reception result transmission circuit 203 employs a method that does not require prior recognition whether the signal sequence received by the LVDS reception circuit 202 is recording control data or connection confirmation data. The connection confirmation data includes only the start command 23 in the recording control data.

[0040] If the recording head 11 is properly connected to the recording device 2, the recording head 11 expects recording data 24 and CRC command 25 following the start command 23. However, if connection confirmation data is received, the CRC command 25 will not be received between the trigger signal 21 and the next trigger signal 22. In this case, the reception result transmission circuit 203 sets the reception error flag to "1" as shown in Figure 4(d). The default value for the reception error flag (when reception is normal) is "0", and "1" indicates that there is an error in the received signal sequence.

[0041] When the CPU 101 checks the connection of the recording head 11, it obtains the value of the reception error flag from the reception result transmission circuit 203. If this value is "1", the CPU 101 determines that the recording head 11 is properly installed in the recording device 2. This is because the connection check data includes only the start command 23 and does not include the CRC command 25, so if it is properly transmitted to the recording head 11, it will always be determined to be a reception error. Conversely, when the CPU 101 checks the connection of the recording head 11, if the reception error flag is "0" as shown in Figure 4(e), it can be determined that there is a connection problem with the recording head 11. In the case where the recording device 2 is configured to have multiple recording heads 11 with different ink types, this connection problem check is performed for each recording head 11.

[0042] While this mechanism can be used to check for connection problems in the recording head 11, if the clock signal frequency is high (short period), it may be affected by the time constant on the LVDS signal line 115, leading to misjudgments. In particular, differential transmission has advantages for high-frequency data transmission, making it possible to transmit recording control data from the control unit 100 to the recording head 11 at a faster speed. However, this can be affected by the time constant. Figure 5 is an explanatory diagram.

[0043] In Figure 5, CLK_DEF is the voltage difference between the CLK+ signal and the CLK- signal transmitted from the LVDS transmission circuit 113, and is a clock signal with period T1. Period T1 is the transmission period of the recording control data. DATA_DEF0 is the voltage difference between the DATA+ signal and the DATA- signal transmitted from the LVDS transmission circuit 113, and is a data signal.

[0044] The data signal is synchronized with the clock signal and is delayed by 1 / 4 period relative to the clock signal. This delayed signal may be generated by the LVDS transmitting circuit 113 at the source or by the LVDS receiving circuit 202. By latching the data signal (DATA_DEF0) on the rising and falling edges of the clock signal (CLK_DEF) and comparing its voltage value with a voltage threshold TH, the received data signal sequence can be converted into digital data. In the illustrated example, the data obtained from the data signal (DATA_DEF0) is "1010".

[0045] Suppose a contact failure occurs at contact C4, as illustrated in Figure 3(b). If there is no parasitic capacitance in the head circuit 200 and the time constant is 0, the potential of the termination resistor 202b will be equal, and the data signal obtained on the LVDS receiving circuit 202 side will be "0000" as shown in DATA_DEF1.

[0046] In the example in Figure 4(c), if the start command is "1010", then in the case of DATA_DEF0 in Figure 5, the start command is recognized. Subsequently, since no CRC command is received, the reception result transmission circuit 203 sets the reception error flag to "1". As a result, the CPU 101, having obtained the reception error flag, determines that the connection of the recording head 11 is normal. In the case of DATA_DEF1 in Figure 5, the start command is not recognized, so the reception error flag remains at the default value of "0". As a result, the CPU 101, having obtained the reception error flag, determines that the connection of the recording head 11 is faulty.

[0047] On the other hand, in reality, a time constant exists due to parasitic capacitance within the head circuit 200 and resistance of the signal lines, and if the time constant is above a certain level, the data signal will be affected. If a contact failure occurs at contact C4 as illustrated in Figure 3(b), a voltage difference will occur as shown in DATA_DEF2, unlike DATA_DEF1 in Figure 5, and the data "1010" may be obtained. If the start command is "1010", in the case of DATA_DEF2 in Figure 5, the start command is recognized, and since the CRC command is not received thereafter, the reception result transmission circuit 203 will set the reception error flag to "1". As a result, the CPU 101, having obtained the reception error flag, will incorrectly determine that the connection of the recording head 11 is normal.

[0048] Therefore, in this embodiment, during the connection confirmation process of the recording head 11, the period T1 (first period) is set to a period T2 (second period) that is longer than the period T1. This prevents misjudgments caused by the time constant. Figure 6 shows an example.

[0049] Similar to the example in Figure 5, CLK_DEF is the voltage difference between the CLK+ signal and the CLK- signal transmitted from the LVDS transmission circuit 113, and is the clock signal. However, its period T2 is longer than its period T1.

[0050] The period T2 is set to a time that is greater than or equal to the period T1 plus a time constant determined by experimentation or other means. For example, if the period T1 during the transmission of recording control data is 1.0 nsec (frequency: 1 GHz) and the time constant on the signal line is 0.5 nsec, then the period T2 is 2 nsec (frequency: 500 MHz). Expressed as an equation, for example, T2 = T1 + time constant + coefficient, or T2 = T1 + time constant × coefficient (>1), or T2 = (T1 + time constant) × coefficient (>1).

[0051] DATA_DEF0 is a data signal that is the voltage difference between the DATA+ signal and the DATA- signal, similar to the example in Figure 5, and is delayed by 1 / 4 period relative to the clock signal. Then, similar to the example in Figure 5, the data signal (DATA_DEF0) is latched on the rising and falling edges of the clock signal (CLK_DEF), and its voltage value is compared with the voltage threshold TH, thereby converting the received data signal sequence into digital data "1010".

[0052] DATA_DEF2, like the example in Figure 5, shows an example where a contact failure occurs at contact C4, as illustrated in Figure 3(b), and the time constant is affecting the data signal. However, by lengthening the period T2, the timing of the voltage fluctuation shifts from the timing of comparison with the voltage threshold TH (rising and falling edges of the clock signal). As a result, the obtained data becomes "0000", and, like the example of DATA_DEF1 in Figure 5, the reception error flag remains at the default value of "0". Consequently, the CPU 101, having acquired the reception error flag, determines that the connection of the recording head 11 is faulty. In this way, the inspection accuracy regarding connection failures of the recording head 11 can be improved in this embodiment.

[0053] <Example of processing> An example of the connection inspection process for the recording head 11 executed by the CPU 101 will be described. Figure 7(a) is a flowchart of this example. The process shown in this figure is executed, for example, when the recording device 2 is powered on or when the user notifies the system via the operation unit 420 that they have performed a replacement operation for the recording head 11.

[0054] In S1, the CPU 101 instructs the connection confirmation data generation circuit 114 to generate connection confirmation data. In the example in Figure 6, the connection confirmation data generation circuit 114 generates data that includes "1010" as a start command but does not include a CRC command. In S2, the CPU 101 instructs the connection confirmation data generated by the connection confirmation data generation circuit 114 to be transmitted to the recording head 11 via the LVDS transmission circuit 113 using a differential voltage method. At this time, the CPU 101 sets (instructs) the LVDS transmission circuit 113 to use a clock signal period T2 for transmitting connection confirmation data, rather than the period T1 used for transmitting recording control data. Known techniques can be used to switch the signal period. In the head circuit 200 of the recording head 11, the connection confirmation data is received by the LVDS receiving circuit 202, and the reception result transmission circuit 203 sets the reception error flag to "1" or "0" based on the received data.

[0055] In S3, the CPU obtains a reception error flag from the reception result transmission circuit 203 and determines whether the obtained reception error flag indicates error information ("1"). If it indicates error information, the process proceeds to S4, and the status of the recording device 2 is set to indicate that the recording head 11 is properly connected. If it does not indicate error information, the process proceeds to S5, and the status of the recording device 2 is set to indicate that there is a connection problem with the recording head 11. If it is set that there is a connection problem, corrective processing such as notifying the user is performed.

[0056] <Second Embodiment> In the first embodiment, the period T2 was set to a uniform period regardless of individual differences in the recording heads 11, but it may be set for each recording head 11. The time constant will differ depending on the individual differences in the recording heads 11. By setting the period T2 for each recording head 11, the inspection time can be shortened for recording heads 11 with a small time constant.

[0057] The individual time constants of the recording heads 11 can be measured experimentally at the time of shipment or other times. For example, a recording device 2 for measuring time constants is prepared in advance. The recording heads 11 are mounted on the prepared recording device 2, and data communication is performed between the recording device 2 and the recording heads 11 using the LVDS signal line 115. At this time, the time required for the rising edge of the signal transmitted from the recording device 2 to the recording heads 11 (time constant) is measured using a measuring instrument. Subsequently, the measured time constant is written to the memory 206 (storage means) of the head circuit 200 as time constant information unique to that recording head 11 and stored. As a result, after the recording heads 11 have been used, the time constant information can be read from the memory 206 by any recording device 2.

[0058] In this embodiment, an example of the connection inspection process for the recording head 11 executed by the CPU 101 will be described. Figure 7(b) is a flowchart of this example. The process shown in the figure is executed, for example, when the power to the recording device 2 is turned on, or when the user notifies via the operation unit 420 that they have performed a replacement operation for the recording head 11.

[0059] In S11, the CPU 101 (acquisition means) acquires (reads) time constant information from the memory 206 of the recording head 11. If time constant information cannot be acquired, it can be determined at that point that there is a connection problem with the recording head 11. In S12, the CPU 101 (setting means) sets the period T2 based on the time constant information acquired in S11. An example of a method for setting the period T2 considering the time constant is as described in the first embodiment.

[0060] The processing in S13 to S17 is the same as the processing in S1 to S5 in Figure 5(a). In S13, the CPU 101 instructs the connection confirmation data generation circuit 114 to generate connection confirmation data. In S14, the CPU 101 instructs the connection confirmation data generated by the connection confirmation data generation circuit 114 to be transmitted from the LVDS transmission circuit 113 to the recording head 11 using the differential voltage method. At this time, the CPU 101 sets (instructs) the LVDS transmission circuit 113 to have a period T2 set in S12 as the period of the clock signal. In the head circuit 200 of the recording head 11, the connection confirmation data is received by the LVDS receiving circuit 202, and the reception result transmission circuit 203 sets the reception error flag to "1" or "0" based on the received data.

[0061] In S15, the CPU obtains a reception error flag from the reception result transmission circuit 203 and determines whether the obtained reception error flag indicates error information ("1"). If it indicates error information, the process proceeds to S16, and the status of the recording device 2 is set to indicate that the recording head 11 is properly connected. If it does not indicate error information, the process proceeds to S17, and the status of the recording device 2 is set to indicate that there is a connection problem with the recording head 11. If it is set that there is a connection problem, corrective processing such as notifying the user is performed.

[0062] <Other Embodiments> The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0063] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0064] 2 recording devices, 11 recording heads

Claims

1. A recording head having a recording element, A recording device comprising a transmitting means that transmits data signals and clock signals by differential transmission method via multiple signal lines, The recording head includes receiving means for receiving the clock signal and the data signal, A recording device characterized in that the data signal includes a first data sequence transmitted when the clock signal is in a first period, and a second data sequence transmitted when the clock signal is in a second period that is longer than the first period.

2. The recording device according to claim 1, characterized in that each of the data signal and the clock signal is transmitted via a pair of differential signal lines in which the polarity is reversed relative to each other.

3. Having an operating means, The recording head is detachable from the recording device. The recording apparatus according to claim 1, characterized in that, after notification is given by the user that the recording head has been replaced via the operating means, the period of the clock signal is changed from the first period to the second period.

4. The recording head is detachable from the recording device. The recording device according to claim 1, characterized in that, after the power of the recording device is turned on, the period of the clock signal is changed from the first period to the second period.

5. The first data sequence includes a first signal sequence indicating the start of transmission and a second signal sequence related to the driving of the recording element. The recording device according to claim 1, characterized in that the second data sequence includes the first signal sequence but does not include the second signal sequence.

6. The first data sequence is transmitted in connection with the driving operation of the recording element, The recording device according to claim 5, characterized in that the second data sequence is transmitted after the power of the recording device is turned on or after the replacement of the recording head is notified by user operation.

7. The recording device according to claim 1, characterized in that the plurality of signal lines have termination elements on the recording head side.

8. The recording device according to claim 1, characterized in that the data signal is transmitted with a predetermined phase shift relative to the clock signal.

9. The recording head is detachable from the recording device. The recording device according to claim 5, further comprising control means for determining the connection state of the recording head based on the reception result of the first signal sequence.

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