Inkjet recording device

Abstract

The present invention provides an inkjet recording apparatus capable of preventing erroneous printing even if an abnormality occurs in the signal propagation between the control unit that processes transport distance information and the control unit that performs printing. [Solution] The inkjet recording device 1 comprises an image forming unit 50 which includes a head module 513 that forms an image by ejecting ink onto a recording medium 100 and a head control unit 512 that ejects ink by transmitting a drive signal to the head module 513; a detection unit 40 that transmits a detection signal to the head control unit 512 when it detects the recording medium 100; and a main control unit 10 which controls the timing of ink ejection by the head module 513 by transmitting a trigger signal based on image data to the head control unit 512. The head control unit 512 transmits a drive signal to the head module 513 when it has received a detection signal when it has received a trigger signal.

Description

Technical Field

[0001] The present invention relates to an inkjet recording apparatus.

Background Art

[0002] Conventionally, an inkjet recording apparatus that ejects ink from nozzles of a head to record an image on a recording medium is known. In such an inkjet recording apparatus, a configuration is generally adopted in which the position of the recording medium is acquired based on a detection unit provided immediately before the image forming unit, conveyance information from the starting position, etc., and the timing of starting image formation is controlled.

[0003] For example, in Patent Document 1, when a downstream sensor that detects a recording medium immediately before the image forming unit fails, an inkjet recording apparatus is described that specifies the position of the recording medium from the conveyance distance after the upstream sensor detects it and performs image formation.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in an inkjet recording apparatus, for the purpose of improving processing accuracy, a control unit that processes conveyance distance information and a control unit that performs printing processing may be provided separately. And when the configuration of Patent Document 1 is applied to such an inkjet recording apparatus, there is a risk of malfunction when an abnormality occurs in signal propagation between the two control units.

[0006] This invention has been made in view of the above circumstances. Its purpose is to provide an inkjet recording apparatus that can prevent erroneous printing even when an abnormality occurs in the signal propagation between the control unit that processes transport distance information and the control unit that performs printing. [Means for solving the problem]

[0007] To solve the above problems, the invention described in claim 1 is an inkjet recording apparatus, A transport unit that transports the recording medium in the transport direction, A head module that forms an image by ejecting ink onto the recording medium, A head control unit that ejects ink by transmitting a drive signal to the head module, A detection unit transmits a detection signal indicating the detection of the recording medium to the head control unit, The system includes a main control unit that controls the timing of ink ejection by the head module by transmitting a trigger signal based on image data to the head control unit, If the head control unit receives the detection signal when it receives the trigger signal, it transmits the drive signal to the head module.

[0008] The invention described in claim 2 is an inkjet recording apparatus as described in claim 1, The detection unit is located upstream of the head module in the transport direction.

[0009] The invention described in claim 3 is an inkjet recording apparatus according to claim 1 or 2, Multiple head units, each comprising the head module and the head control unit, are provided along the transport direction.

[0010] The invention described in claim 4 is an inkjet recording apparatus as described in claim 3, The head unit comprises a first head unit located at the upstream end in the transport direction and a second head unit excluding the first head unit. The head control unit of the second head unit receives the detection signal from the head control unit of the adjacent head unit located upstream in the transport direction.

[0011] The invention described in claim 5 is an inkjet recording apparatus as described in claim 4, While the head control unit is transmitting the drive signal to the corresponding head unit, it transmits the detection signal to the head control unit of the adjacent head unit on the downstream side in the transport direction.

[0012] The invention described in claim 6 is an inkjet recording apparatus as described in claim 5, If the head control unit stops receiving the detection signal while transmitting the drive signal to the corresponding head unit, it stops transmitting the drive signal.

[0013] The invention described in claim 7 is an inkjet recording apparatus as described in claim 4, The head control unit of the first head unit is directly connected to the detection unit to receive the detection signal.

[0014] The invention described in claim 8 is an inkjet recording apparatus as described in claim 4, The storage unit comprises a setting for the minimum length of the usable recording medium in the transport direction, The detection unit is positioned within the minimum length from the printing start position of the first head unit.

[0015] The invention described in claim 9 is an inkjet recording apparatus according to claim 1 or 2, The transport unit includes the detection unit.

[0016] The invention described in claim 10 is an inkjet recording apparatus according to claim 1 or 2, Multiple detection units are provided in the width direction perpendicular to the transport direction. (When the head control unit receives the detection signal from at least one of the plurality of detection units when receiving the trigger signal, the head control unit transmits the drive signal to the head module.)

[0017] (The invention according to claim 11 is an inkjet recording apparatus according to claim 1 or 2,) (The main control unit transmits the medium length information of the recording medium together with the trigger signal,) (When the head control unit stops receiving the detection signal during transmission of the drive signal, the head control unit determines whether to continue transmission of the drive signal based on the medium length information.)

[0018] (The invention according to claim 12 is an inkjet recording apparatus according to claim 1 or 2,) (The main control unit transmits the ink ejection time information together with the trigger signal,) (When the head control unit stops receiving the detection signal during transmission of the drive signal, the head control unit determines whether to continue transmission of the drive signal based on the ink ejection time information,) (When the detection signal is received again within the ink ejection time, the drive signal is transmitted based on the reception of the trigger signal and the detection signal.) ([Advantages of the Invention])

[0019] (According to the present invention, even when an abnormality occurs in the signal propagation between the control unit that processes the conveyance distance information and the control unit that performs the printing process, misprinting can be prevented.) ([Brief Description of the Drawings])

[0020] [Figure 1] (It is a schematic side view of the inkjet recording apparatus seen from the width direction.) [Figure 2] (It is a block diagram of the inkjet recording apparatus.) [Figure 3] (It is a schematic diagram of the transmission path of various signals in the inkjet recording apparatus.) [Figure 4] (It is a ladder chart of the image forming process.) [Modes for carrying out the invention]

[0021] Hereinafter, an inkjet recording apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. In the following description, components having the same function and configuration will be denoted by the same reference numerals, and their descriptions will be omitted.

[0022] [Overall configuration of an inkjet recording device] Figure 1 is a schematic side view showing the main components of the inkjet recording device 1. Figure 2 is a block diagram showing the functional configuration of the inkjet recording device 1. The inkjet recording device 1 comprises a main control unit 10, a paper feeding unit 20, a transport unit 30, a detection unit 40, an image forming unit 50, and a paper discharge unit 60.

[0023] The transport unit 30 of the inkjet recording device 1, under the control of the main control unit 10, transports the recording medium 100 from the paper feeding unit 20 to the paper discharge unit 60 via the image forming unit 50. The image forming unit 50 forms an image by ejecting ink onto the transported recording medium 100.

[0024] Furthermore, the recording medium 100 is not limited to paper such as plain paper or coated paper. Various media capable of fixing ink deposited on their surface can be used as the recording medium 100, such as cloth or sheet-like resin.

[0025] Furthermore, in the following, the X, Y, and Z directions refer to the directions shown in Figure 1. Also, in the following, the X, Y, and Z directions will be referred to as the width direction, conveying direction, and height direction, respectively.

[0026] (Main control unit) The main control unit 10 controls each component of the inkjet recording device 1. The main control unit 10 is connected to each component of the inkjet recording device 1. The main control unit 10 includes a CPU (Central Processing Unit) 11, RAM (Random Access Memory) 12, and ROM (Read Only Memory) 13, etc.

[0027] The CPU 11 reads and executes various programs and data from memory units such as the ROM 13, according to the processing content. The CPU 11 also controls the operation of each part of the inkjet recording device 1 according to the executed processing content. The RAM 12 temporarily stores the various programs and data processed by the CPU 11.

[0028] ROM13 is a non-volatile storage unit such as an HDD (Hard Disk Drive), SSD (Solid State Drive), or flash memory. ROM13 stores various programs and data that are read by the CPU 11, etc.

[0029] ROM 13 stores various settings related to image formation by the head unit 51. In particular, ROM 13 stores settings for the recording medium 100 on which image processing can be performed. Specifically, these settings include the minimum length of the recording medium 100 in the transport direction.

[0030] Furthermore, when the CPU 11 receives a print job from another device, it generates image data by performing known RIP (Raster Image Processor) processing on the print data included in the print job. The CPU 11 also generates trigger signals based on the generated image data and various signals such as the transport start signal and transport distance signal received from the main transport unit 32 (described later), and transmits these signals along with the image data of each color to each head control unit 512 (described later) to perform image forming processing.

[0031] (Paper feed section) The paper feeding unit 20 stores the recording medium 100 before image formation. Under the control of the main control unit 10, the paper feeding unit 20 transports the recording medium 100 to the transport unit 30. The paper feeding unit 20 includes a paper feeding tray 21, etc.

[0032] {paper tray} The paper feed tray 21 is a plate-shaped member that stores the recording media 100. The paper feed tray 21 is provided so that one or more recording media 100 can be placed on it. The paper feed tray 21 moves up and down according to the amount of recording media 100 placed on it. Through this up and down movement, the paper feed tray 21 is held in a position where the uppermost recording media 100 is transported by the first transport mechanism 31 of the transport unit 30.

[0033] (Transportation section) The transport unit 30 transports the recording medium 100 in the transport direction and transfers it from the paper feeding unit 20 through the image forming unit 50 to the paper discharge unit 60. The transport unit 30 includes a first transport mechanism 31, a main transport unit 32, a second transport mechanism 33, and the like.

[0034] {First conveying mechanism} The first transport mechanism 31 transports the recording medium 100 from the paper feed tray 21 to the main transport unit 32. The first transport mechanism 31 drives a belt 313 to transport the recording medium 100 on the belt 313. The belt 313 is ring-shaped, and the inside of the ring is supported by a plurality of rollers 311 and 312. The first transport mechanism 31 transfers the uppermost recording medium 100 placed on the paper feed tray 21 onto the belt 313 and transports the recording medium 100 along the belt 313.

[0035] Furthermore, the first conveying mechanism 31 includes a transfer unit 314. The transfer unit 314 is positioned between the first conveying mechanism 31 and the main conveying unit 32. The transfer unit 314 includes a claw portion 314a and a transfer drum 314b, etc.

[0036] The claw portion 314a is a cylindrical member that supports one end of the recording medium 100 that has been transported by the first transport mechanism 31. The transfer drum 314b is a member that guides the recording medium 100 supported by the claw portion 314a. The transfer unit 314 picks up the recording medium 100 on the first transport mechanism 31 with the claw portion 314a and guides it along the outer surface of the transfer drum 314b. Through this operation, the transfer unit 314 transfers the recording medium 100 to the main transport unit 32.

[0037] {Main transport unit} The main transport unit 32 transports the recording medium 100 transported from the first transport mechanism 31 so that it passes through the detection unit 40 and the image forming unit 50. The main transport unit 32 is a cylindrical transport drum that supports the recording medium 100 along its cylindrical outer surface and transports the recording medium 100 in the transport direction as it rotates with the width direction as the axis of rotation. The transport surface of the main transport unit 32 faces the detection unit 40 and the image forming unit 50. The recording medium 100 transported by the main transport unit 32 undergoes image forming processing by the image forming unit 50.

[0038] The main transport unit 32 is equipped with various sensors. These sensors are connected to the main control unit 10 and transmit various signals to the main control unit 10 based on the signals they acquire. The signals that the sensors of the main transport unit 32 transmit to the main control unit 10 include, for example, a transport start signal that notifies the main transport unit 32 that one recording medium 100 has started to be transported, and a transport distance signal that is synchronized with the transport drive of the main transport unit 32.

[0039] The main transport unit 32 is not limited to an image forming drum; it is simply required to transport the recording medium 100 in the transport direction so that it passes below the detection unit 40 and the image forming unit 50. For example, the main transport unit 32 may be configured to transport the recording medium 100 placed on a circular transport belt by rotating rollers inside the transport belt, similar to the first transport mechanism 31.

[0040] {Second transport mechanism} The second transport mechanism 33 has substantially the same configuration as the first transport mechanism 31. That is, the second transport mechanism transports the recording medium 100 by driving a ring-shaped belt 333 on which multiple rollers 331 and 332 support the inside. The second transport mechanism 33 is equipped with a cylindrical transfer roller 334. The transfer roller 334 transfers the recording medium 100 from the main transport unit 32 to the second transport mechanism 33. The second transport mechanism 33 transports the recording medium 100 that has been transferred onto the belt 333 by the transfer roller 334 and sends it to the paper discharge unit 60.

[0041] (Detection unit) The detection unit 40 is a sensor for detecting the recording medium 100 being transported by the main transport unit 32, located upstream of the head unit 51 of the image forming unit 50 in the transport direction. The detection unit 40 transmits a detection signal to the head control unit 512 of the first head unit 51a (described later) while detecting the recording medium 100, and does not transmit a detection signal when it does not detect the recording medium 100. The detection unit 40 is installed within the minimum length in the transport direction of the recording medium 100 stored in the ROM 13 with respect to the installation position of the first head unit 51a.

[0042] (Image forming unit) The image forming unit 50 forms an image on the recording medium 100 by ejecting ink. The image forming unit 50 includes a plurality of head units 51 and an image reading unit 52, etc.

[0043] {Head Unit} The head unit 51 ejects ink droplets from the nozzles of the head module 513 onto the recording medium 100 to form an image. The head unit 51 is provided with separate units for ejecting C (cyan), M (magenta), Y (yellow), and K (black) inks. In Figure 1, the head units 51 ejecting Y, M, C, and K inks are arranged in order from the upstream side in the transport direction. In this invention, for convenience, the head unit 51 located at the upstream end in the transport direction is referred to as the first head unit 51a, and the other head units 51 excluding the first head unit 51a are referred to as the second head unit 51b.

[0044] In this embodiment, the image forming unit 50 is provided with multiple head units 51 arranged in the width direction, each head unit having a length (width) that covers the entire recording medium 100. That is, the inkjet recording device 1 is a one-pass line-head type inkjet recording device. The head unit 51 is configured by arranging head modules 513 on a carriage 511. The number of head units 51 provided in the image forming unit 50 may be three or fewer, or five or more.

[0045] The ink ejected by the head unit 51 is, for example, gel ink containing a gelling agent. Gel ink undergoes a phase change between a gel state and a liquid (sol) state depending on the temperature. Gel ink has a phase change temperature of, for example, 40 to 100°C, and uniformly liquefies (becomes a sol) when heated above this temperature. On the other hand, gel ink remains gelled at normal room temperature, i.e., around 0 to 30°C. Therefore, the ink in the head unit 51 is heated to an appropriate temperature by an ink heater (not shown) or the like to become a sol. After being ejected and landing on the recording medium 100, it transitions to a gel state appropriately while being transported by the main transport unit 32.

[0046] The ink ejected by the head unit 51 may be UV ink. However, in this case, a fixing unit is required downstream of the head unit 51 in the transport direction, which irradiates the ink with light of a predetermined energy to fix it to the recording medium 100.

[0047] <carriage> The head unit 51 consists of a carriage 511, a head control unit 512, and a head module 513, etc. The carriage 511 has, for example, a belt stretched between two pulleys that are rotated by a motor (not shown). The head control unit 512 and the head module 513 are mounted on the carriage 511.

[0048] The carriage 511 scans the mounted head control unit 512 and head module 513 in the width direction by the rotational operation of a motor based on a drive signal output by the main control unit 10. A known maintenance unit (not shown) is provided on the width direction side of the head unit 51. The maintenance unit performs maintenance on the head unit 51 that has been scanned in the width direction by the carriage 511 as described above.

[0049] <Head Control Unit> The head control unit 512 is a control board for the head modules 513 provided in each head unit 51. Based on the corresponding color image data, synchronization signal, and trigger signal transmitted from the main control unit 10, the head control unit 512 transmits a drive signal to the corresponding head module 513.

[0050] In detail, the head control unit 512 has multiple terminals. As shown in Figure 3, one terminal is connected to the main control unit 10 by a predetermined signal line. The terminals of the first head unit 51a are connected to the detection unit 40 and the head control unit 512 of the adjacent second head unit 51b on the downstream side in the transport direction. The two terminals of the second head unit 51b, excluding the downstream end in the transport direction, are connected to the head control units 512 of other adjacent head units 51 on the upstream and downstream sides in the transport direction.

[0051] In this configuration, multiple head control units 512 are connected in a daisy-chain. In this configuration, the head control unit 512 of the first head unit 51a receives a detection signal from the detection unit 40. Also in this configuration, the head control unit 512 of the second head unit 51b receives a detection signal from the head control unit 512 of another head unit 51 adjacent to it on the upstream side in the transport direction.

[0052] The main control unit 10 then transmits a trigger signal to the head control unit 512 of the corresponding head module 51 at a timing based on the image data. When the head control unit 512 receives the trigger signal, if it has also received a detection signal, it transmits a drive signal to the corresponding head module 513 to eject ink. In addition, when the head control unit 512 transmits the drive signal, it transmits a detection signal to the adjacent head unit 51 on the downstream side in the transport direction.

[0053] In this manner, the head control unit 512 receives a trigger signal from the main control unit 10 and a detection signal from the detection unit 40 or from the head control unit 512 of another adjacent head unit 51 on the upstream side in the transport direction. When the head control unit 512 receives both the trigger signal and the detection signal, it sends a drive signal to the head module 513 to eject ink.

[0054] {Head Module} The head module 513 is composed of multiple inkjet heads. Each inkjet head includes a tank for storing liquid, multiple nozzles from which the liquid is ejected, a flow path connecting the tank and the nozzles, and an actuator that applies pressure to the ink supplied to the nozzles. The actuator is, for example, a piezoelectric element. The actuator applies pressure fluctuations to the liquid supplied from the tank to the nozzles via the flow path in response to a voltage signal of a predetermined drive waveform applied from the head control unit 512 in order to eject droplets from the nozzles N. The head module 513 is composed of multiple such inkjet heads arranged in the width direction.

[0055] {Image reading section} The image reading unit 52 is positioned downstream of the head unit 51 in the transport direction, and is capable of reading the surface (image forming surface) of the recording medium 100. The image reading unit 52 is, for example, a line sensor. The image reading unit 52 acquires reading data of the image formed on the surface of the recording medium 100 by the head unit 51. The image reading unit 52 transmits the acquired reading data to the main control unit 10. The main control unit 10, upon receiving the reading data, appropriately modifies the content to be transmitted to the head control unit 512 in the subsequent image forming process based on its contents, thereby feeding back the image forming results from the preceding image forming process to the subsequent image forming process.

[0056] (Paper output section) The paper discharge unit 60 discharges the recording medium 100 that has undergone image formation processing in the image forming unit 50. The paper discharge unit 60 is equipped with a plate-shaped paper discharge tray 61, etc. The recording medium 100, which has been fed out by the second transport mechanism 33, is placed on the paper discharge tray 61. The paper discharge unit 60 stores the recording medium 100 until the user removes it.

[0057] [Image Forming Processing] The image formation process using this inkjet recording device 1 will be explained based on the ladder chart in Figure 4.

[0058] First, the main control unit 10 acquires a print job from another device (step S101). The main control unit 10 generates RIP image data for each color by performing known RIP (Raster Image Processor) processing on the print data included in the print job (step S102).

[0059] The main control unit 10 starts transporting the recording medium 100 by transmitting drive signals to the paper feeding unit 20 and the transport unit 30 (step S103). The head control unit 512 of the first head unit 51a receives a detection signal from the detection unit 40 that has detected the recording medium 100. The main control unit 10 transmits a trigger signal and image data of the corresponding color to the head control unit 512 of the first head unit 51a at a predetermined timing based on the transport start signal and transport distance signal received from the sensor of the transport unit 30 (step S104).

[0060] When the trigger signal is received from the main control unit 10, the head control unit 512 of the first head unit 51a determines whether or not it has received a detection signal from the detection unit 40 (step S105). If the detection signal has not been received from the detection unit 40 at the time the trigger signal is received from the main control unit 10 (step S105; No), the head control unit 512 of the first head unit 51a determines that the trigger signal is a false signal. Therefore, the head control unit 512 proceeds to step S105 and waits for the reception of the trigger signal.

[0061] If the detection unit 40 receives a detection signal at the same time that the main control unit 10 receives a trigger signal (step S105; Yes), the head control unit 512 transmits a head drive signal to the head module 513 (step S106). Upon receiving the head drive signal, the head module 513 ejects ink. Also, the head control unit 512 of the first head unit 51a transmits a detection signal to the head control unit 512 of the second head unit 51b, which is the adjacent head unit 51 on the downstream side in the transport direction, in synchronization with step S106 (step S107).

[0062] The head control unit 512 of the second head unit 51b receives a detection signal from the upstream head unit 51. Then, the main control unit 10 transmits a trigger signal and corresponding color image data to the second head unit 51b at a predetermined timing based on the signal received from the sensor of the transport unit 30 (step S108).

[0063] When the trigger signal is received from the main control unit 10, the head control unit 512 of the second head unit 51b determines whether or not it has received a detection signal from the adjacent head unit 51 upstream (step S109). If, when the trigger signal is received from the main control unit 10, the head control unit 512 of the second head unit 51b has not received a detection signal from the head control unit 512 of the upstream head unit 51 (step S109; No), the head control unit 512 of the second head unit 51b determines that the trigger signal is a false signal. Therefore, the head control unit 512 proceeds to step S109 and waits for the reception of the trigger signal.

[0064] If the head control unit 512 of the upstream head unit 51 receives a detection signal from the head control unit 512 at the same time as receiving a trigger signal from the main control unit 10 (step S109; Yes), the head control unit 512 of the second head unit 51b sends a head drive signal to the head module 513 (step S110). As a result, ink is ejected from the head module 513. The head control unit 512 of the second head unit 51b also determines whether it is located at the downstream end in the transport direction among the head units 51 (step S111). If it is located at the downstream end in the transport direction (step S111; Yes), there is no head unit 51 to which a detection signal should be sent, and the series of image forming processes is terminated. If it is not located at the downstream end in the transport direction (step S111; No), the head control unit 512 sends a detection signal to the head control unit 512 downstream in the transport direction in sync with step S110 (step S112), and then proceeds to step S109.

[0065] [Effects of the Embodiment] As described above, the inkjet recording apparatus 1 according to this embodiment includes a transport unit 30 that transports the recording medium 100 in the transport direction. The inkjet recording apparatus 1 also includes an image forming unit 50 which comprises a head module 513 that forms an image by ejecting ink onto the recording medium 100, and a head control unit 512 that ejects ink by transmitting a drive signal to the head module 513. The inkjet recording apparatus 1 also includes a detection unit 40 that transmits a detection signal to the head control unit 512 when it detects the recording medium 100. The inkjet recording apparatus 1 also includes a main control unit 10 that controls the timing of ink ejection by the head module 513 by transmitting a trigger signal based on image data to the head control unit 512. The head control unit 512 transmits a drive signal to the head module 513 when it receives a detection signal when it receives a trigger signal. With this configuration, the head control unit 512 ejects ink from the head unit 51 only when it receives both a trigger signal and a detection signal, so that misprints can be prevented even if there is an abnormality in the propagation of the trigger signal from the main control unit 10 to the head control unit 512.

[0066] [Other configurations] Although the present invention has been described in detail based on embodiments of the present invention, the present invention is not limited to the embodiments described above. It goes without saying that the present invention can be modified in various ways, including to a extent equivalent to the scope of the invention described in the claims.

[0067] For example, the above example illustrates a configuration in which a detection unit 40 is separate from the main transport unit 32, but it is not limited to this. That is, the transport unit 30 (especially the main transport unit 32) may be equipped with a sensor corresponding to the detection unit 40 and transmit a transport start signal and a transport distance signal.

[0068] Furthermore, although the above example illustrates a configuration with one detection unit 40, the system is not limited to this, and multiple detection units 40 may be provided in the width direction. The head control unit 512 of the first head unit 51a may also be configured to transmit a head drive signal when it receives a detection signal from any one of the detection units 40 upon receiving a trigger signal. With this configuration, even if one of the detection units 40 malfunctions, image formation can continue as long as not all of the detection units 40 malfunction simultaneously.

[0069] Furthermore, although the above assumes that each of the multiple head units 51 is equipped with a head control unit 512, this is not the only option. That is, a single head control unit 512 may control multiple head units 51. Alternatively, a configuration with fewer head control units 512 than the number of head units 51 is also possible.

[0070] Furthermore, the head control unit 512 may stop transmitting the drive signal if it stops receiving a detection signal while transmitting the drive signal. With this configuration, if the length of the recording medium 100 in the transport direction is shorter than the length of the recording medium 100 included in the print job in the transport direction, it is possible to prevent the main transport unit 32 from being soiled by the ink ejection of the head unit 51.

[0071] On the other hand, a malfunction of the detection unit 40 may cause the head control unit 512 to stop receiving detection signals. Therefore, if the head control unit 512 stops receiving detection signals while transmitting drive signals, it may decide whether to continue transmitting drive signals and continue the image forming process, depending on the length of the transport direction of the recording medium 100 included in the print job. If it decides to continue the image forming process and then starts receiving detection signals again while transmitting drive signals, it may return to the original image forming process.

[0072] Alternatively, if the head control unit 512 stops receiving a detection signal while transmitting a drive signal, it may determine whether to continue transmitting the drive signal and continue the image forming process, according to the ink ejection time information included in the print job. In this configuration as well, if the detection signal is received again while transmitting the drive signal, the system may return to the original image forming process. [Explanation of symbols]

[0073] 1. Inkjet recording device 10 Main Control Unit 30 Conveying section 40 Detection unit 50 Image forming unit 51 Head Unit 51a First head unit 51b Second head unit 512 Head Control Unit 513 Head Module 100 recording media

Claims

1. A transport unit that transports the recording medium in the transport direction, A head module that forms an image by ejecting ink onto the recording medium, A head control unit that ejects ink by transmitting a drive signal to the head module, A detection unit transmits a detection signal indicating the detection of the recording medium to the head control unit, The system includes a main control unit that controls the timing of ink ejection by the head module by transmitting a trigger signal based on image data to the head control unit, The head control unit transmits the drive signal to the head module when it has received the detection signal at the time of receiving the trigger signal.

2. The inkjet recording apparatus according to claim 1, wherein the detection unit is provided upstream of the head module in the transport direction.

3. The inkjet recording apparatus according to claim 1 or 2, comprising a plurality of head units, each composed of the head module and the head control unit, along the transport direction.

4. The head unit comprises a first head unit located at the upstream end in the transport direction, and a second head unit excluding the first head unit. The inkjet recording apparatus according to claim 3, wherein the head control unit of the second head unit receives the detection signal from the head control unit of an adjacent head unit on the upstream side in the transport direction.

5. The inkjet recording apparatus according to claim 4, wherein the head control unit transmits the detection signal to the head control unit of an adjacent head unit downstream in the transport direction while the head control unit is transmitting the drive signal to the corresponding head unit.

6. The inkjet recording apparatus according to claim 5, wherein the head control unit stops transmitting the drive signal if it stops receiving the detection signal while transmitting the drive signal to the corresponding head unit.

7. The inkjet recording apparatus according to claim 4, wherein the head control unit of the first head unit is directly connected to the detection unit to receive the detection signal.

8. The storage unit comprises a setting for the minimum length of the usable recording medium in the transport direction, The inkjet recording apparatus according to claim 4, wherein the detection unit is located within the minimum length from the printing start position of the first head unit.

9. The inkjet recording apparatus according to claim 1 or 2, wherein the transport unit comprises the detection unit.

10. Multiple detection units are provided in the width direction perpendicular to the transport direction. The inkjet recording apparatus according to claim 1 or 2, wherein the head control unit, upon receiving the trigger signal, receives the detection signal from at least one of the plurality of detection units, transmits the drive signal to the head module.

11. The main control unit transmits the media length information of the recording medium along with the trigger signal. The inkjet recording apparatus according to claim 1 or 2, wherein the head control unit determines whether or not to continue transmitting the drive signal based on the media length information if it stops receiving the detection signal while transmitting the drive signal.

12. The main control unit transmits ink ejection time information along with the trigger signal. If the head control unit stops receiving the detection signal while transmitting the drive signal, it determines whether to continue transmitting the drive signal based on the ink ejection time information. The inkjet recording apparatus according to claim 1 or 2, which transmits the drive signal based on the reception of the trigger signal and the detection signal when the detection signal is received again within the ink ejection time.

Images