Recording device

Abstract

To solve such a problem that, in a large-scale device configuration, a large number of long wiring paths are required for print timing signals, and as the number of boards controlling printing increases, the wiring layout deteriorates.SOLUTION: In a recording device having a plurality of print control units, print timing signals connected to the print control units are configured to be sequentially connected.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus, and is particularly suitable for use in a full-line color recording apparatus that performs high-speed, high-quality printing. [Background technology]

[0002] In inkjet recording devices, one of the recording methods advantageous for improving recording speed is the use of a full-line printhead. A full-line printhead is configured with an array of multiple nozzles, and is fixed to the device body with the nozzle array aligned with the paper width direction. Because recording media can be transported while the printhead remains fixed, printing can be performed at higher speeds than with moving printheads. Some recording devices employ a method in which the same number of printheads as the number of colorants (inks) are arranged and different inks are sequentially ejected onto the recording media to form color images. To achieve high productivity, such recording devices tend to become larger overall. This is due to several factors, including larger paper feed / ejection units capable of handling large volumes of recording media, an increasing number of devices along various transport paths, and larger and more numerous devices for stable recording and fixing. Furthermore, as devices become larger, it becomes difficult to perform all processing with a single control unit. Therefore, a configuration in which each function control unit is decentralized and connected via an internal network is being considered. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-159453 Summary of the Invention [Problem to be solved by the invention]

[0004] In a large-scale device configuration like the one described above, a large number of long wiring routes are required to connect the many devices and the control unit. In particular, since the transport and printing operations must be synchronized to operate in a timely manner in order to form a normal image, timing signals must be connected across the control units, which means that the wiring length becomes particularly long and the more boards that control printing are added, the worse the wiring layout becomes and the higher the cost becomes.

[0005] The object of the present invention is to provide a recording device that has multiple print control units and that can shorten the wiring length of the entire device, simplify the wiring layout, and reduce costs by configuring the printing timing signals to be connected sequentially. [Means for solving the problem]

[0006] In order to achieve the above object, the recording device of the present invention is a recording device having a plurality of recording heads each having a plurality of nozzles, a transport unit that transports the recording medium, and a plurality of print control units that control printing by transferring nozzle data to each recording head in synchronization with a timing signal that indicates the transport state, and is characterized in that each print control unit has means for forwarding the received timing signal, and the timing signal is transmitted to the print control unit in serial. [Effects of the Invention]

[0007] According to the present invention, in a recording device having multiple print control units, by configuring the print timing signals to be connected sequentially, the wiring length of the entire device can be shortened, the wiring layout can be simplified, and costs can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view of a recording apparatus according to an embodiment. [Figure 2] 2 is a diagram illustrating the connection relationship and internal configuration of each part according to the embodiment. FIG. [Figure 3]FIG. 2 is an explanatory diagram of a nozzle arrangement of a head according to an embodiment. [Figure 4] FIG. 2 is an explanatory diagram of the positional relationship between a head and a recording medium according to the embodiment. [Figure 5] 4 is a timing chart of timing signals according to the embodiment. [Figure 6] FIG. 2 is a diagram illustrating connections of timing signals according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. A recording apparatus 100 according to this embodiment is a high-speed line printer that uses a continuous sheet wound in a roll as a recording medium.

[0010] FIG. 1 is a schematic cross-sectional view showing the internal configuration of a recording device 100. In a highly productive printer such as this embodiment, the entire device is large, so a multiple cabinet configuration is used to facilitate portability and assembly. The recording device 100 of this embodiment includes an unwinding cabinet 101, a printing cabinet 102, a fixing cabinet 103, and a winding cabinet 104. A continuous sheet M, which is a recording medium, is transported along the sheet transport path indicated by the solid line in the figure and processed in each section.

[0011] The unwinding cabinet 102 includes an unwinding section 112, a transport roller 113, a meandering correction section 114, a rotary encoder 115, and a transport control section 111, and supplies the continuous sheet wound in a roll to the recording device 100. The unwinding section 112 is a unit for holding and supplying the continuous sheet wound in a roll. The unwinding section 112 is configured to store roll paper and pull out and supply the continuous sheet M. The unwinding section 112 is also controlled by a drive motor (not shown) so that it can rotate forward and backward. The transport section 113 is a unit for applying a constant tension to the continuous sheet M between the unwinding section 112 and the transport section 113, and for feeding the continuous sheet M to each unit by driving a motor (not shown).

[0012] The meandering correction unit 114 is a unit for correcting meandering in the width direction of the continuous sheet M. The meandering correction unit 114 is equipped with a meandering detection sensor and a meandering correction roller (not shown), and corrects meandering of the continuous sheet M based on measurements by the meandering detection sensor. The rotary encoder 115 is a unit for detecting the conveyance speed of the continuous sheet M. A signal detected by the rotary encoder 115 is used to control the image formation timing of the print control unit 123 via the conveyance control unit 111. The conveyance control unit 111 controls each unit based on instructions from the overall control unit 121, thereby controlling the conveyance of the continuous sheet M.

[0013] The printing cabinet 102 includes a plurality of print control units 123, a plurality of print heads 124, and an overall control unit 121, and ejects ink onto a supplied continuous sheet to form an image. In this example, the print control units 123 and heads 124 are arranged for each color (Y, M, C, K) along the conveyance direction of the continuous sheet M. Based on instructions from the overall control unit 121, the print control unit 123 transfers print data input from the overall control unit 121 to the heads 124 in accordance with timing signals input from the conveyance control unit 111. Based on the transferred information, the heads 124 eject ink onto the continuous sheet M to form an image. Ink is supplied to the heads 124 from ink tanks (not shown) via tubes. The overall control unit 121 is a unit that controls the entire recording apparatus 100. An operator's instructions to the recording apparatus 100 are given from an operation unit (not shown) provided on the overall control unit 121 and input to the overall control unit 121.

[0014] The fixing cabinet 103 includes a drying fan 132 and a drying control unit 131, and fixes the ink ejected onto the continuous sheet onto the continuous sheet. The drying fan 132 blows air onto the continuous sheet M to reduce the liquid content of the ink. Although the drying fan 132 is used in this example, it is also possible to use a drying method using a heater, or a method of fixing the ink using ultraviolet-curable ink and an ultraviolet irradiation device. The drying control unit 131 controls the drying fan 132 based on instructions from the overall control unit 121.

[0015] The winding cabinet 104 includes a winding section 142 and a transport roller 143, and winds up the continuous sheet processed in each section into a roll. Note that transport of the continuous sheet M from the unwinding section 112 to the winding section 142 in the sheet feed direction is called forward transport, and the opposite direction is called reverse transport. The transport section 143 applies a certain tension to the continuous sheet M between the winding section 142 and the winding section 142 by driving a motor (not shown). The winding section 142 is controlled to rotate forward and reverse by a motor (not shown).

[0016] FIG. 2 is a functional block diagram showing the connection relationship between the overall control unit 121, the transport control unit 111, and the print control unit 123 in the recording device 100, and the internal configuration of each unit.

[0017] The overall control unit 121 is connected to the transport control unit 111 and the print control unit 123 via an internal network 201. Although not shown in the figure, other units such as a drying control unit 131 are also connected to the internal network 121.

[0018] The overall control unit 121 includes a CPU 202, a ROM 204, and a RAM 203, and each unit is connected to the other units within the overall control unit 121 via a bus (not shown). The CPU 202 executes a control program stored in the ROM 204 to control the entire recording device 100. The control program stored in the ROM 204 includes an OS for time-sharing control of multiple load modules using a system clock. The CPU 202 uses the RAM 203 as a work area for processing. The CPU 202 of the overall control unit 121 also performs PDL (Page Description Language) analysis on print data received from an external device, intermediate language processing, and rasterization to generate bitmap image data. The CPU 202 also generates print data by applying halftone processing to the image data. The intermediate data from each process and the generated print data are temporarily stored in the RAM 203. The CPU 202 transfers the generated print data to each print control unit 123 for each color and issues instructions necessary for printing to each control unit.

[0019] Like the transport control unit 111 and the overall control unit 121, the transport control unit 111 has a CPU 211, a RAM 212, and a ROM 213, and the CPU 211 controls processes related to transport of the recording device 100 based on instructions from the overall control unit 121 by executing a control program stored in the ROM 213. The transport control unit 111 also has a control I / F 214, a motor control unit 215, and a print control I / F 216. The control I / F 214 is connected to the in-machine network 201 and constitutes an interface between the overall control unit 121 and the CPU 211. Upon receiving instructions from the overall control unit 121, the CPU 211 instructs the motor control unit 215 to control the speed of the motor.

[0020] Based on instructions from the CPU 211, the motor control unit 215 outputs a pulse signal corresponding to the speed to the motor driver 217. The motor driver 217 drives the transport motors 112, 113, 142, and 143, and controls the acceleration and deceleration of the motors to achieve a printing speed by obtaining speed information based on a signal input from the rotary encoder 115. The print control I / F 216 outputs the signal input from the rotary encoder 115 to the print control unit 123 via the timing signal wiring 206. The print control I / F 216 has a buffer function that adjusts the signal waveform. As the signal wiring length increases, signal quality may deteriorate due to the resistance and capacitance components of the wiring, so a buffer is used to adjust the signal waveform. In addition, because the wiring length between the transport control unit 111 and the print control unit 123 in this example is long, the connection is made using LVDS (Low Voltage Differential Signal) signals.

[0021] Like the overall control unit 121, the print control unit 123 has a CPU 221, RAM 222, and ROM 223. The CPU 221 executes a control program stored in the ROM 223 to control processing related to control of the head 124 based on instructions from the overall control unit 121. The print control unit 123 also has a control I / F 224, a timing signal control unit 225, a timing signal forwarding unit 226, an image acquisition unit 227, and a head control unit 228. The control I / F 224 connects to the in-machine network 201 and constitutes an interface between the overall control unit 221 and the CPU 211. The print data transferred from the overall control unit 121 is temporarily stored in the RAM 222 by the CPU 221. The image acquisition unit 227 is a DMAC (Direct Memory Access Controller) that acquires the print data stored in the RAM 222 and outputs it to the head control unit 228 based on instructions from the CPU 221. Based on the input timing signal, the timing control unit 225 generates an ejection timing signal that matches the resolution of the ejection in the transport direction in the head control unit 228, and outputs the signal to the head control unit 228. The head control unit 228 controls ink ejection from the head by transferring the input print data to the head in synchronization with the ejection timing signal.

[0022] In addition to transferring print data to the head 124, the head control unit 228 also controls the temperature of the head 124 and manages and controls non-ejecting nozzles. The principle of controlling the head ejection timing using timing signals will be described later using Figure 5. The timing signal forward unit 226 receives the input timing signal and outputs it to the next print control unit via the inter-print control unit timing signal wiring 206. The inter-print control unit timing signal wiring 206 exists between each print control unit. The timing signal forward unit 226 has a buffer function that adjusts the signal waveform.

[0023] FIG. 3 is a configuration diagram of the nozzle arrangement of the head 124. FIG. 3 shows the head 124 in which 16,384 nozzles 301 are arranged in a single row in the main scanning direction, which is the width direction of the continuous sheet M, which is the recording medium. In this embodiment, the nozzles 301 are arranged at intervals of one nozzle per 1,200 dpi, resulting in a recording width of approximately 346 mm. By generating print data from the nozzles 301 in advance according to the nozzle resolution, it is possible to control the nozzles based on the print data so that ink is ejected if the print data is 1, and not ejected if the print data is 0. In this example, a head with a single row of nozzles has been described, but the head may be composed of multiple rows of nozzles, or may be configured by arranging multiple heads each formed with a predetermined number of nozzles.

[0024] FIG. 4 is a diagram illustrating the attachment of the heads 124 of each color and their positional relationship with the continuous sheet M. In FIG. 4, the heads 124 are installed so as to be perpendicular to the conveyance direction. By ejecting ink from the heads 124 in synchronization with the feeding of the continuous sheet M in the conveyance direction, an image can be formed at a predetermined resolution in the conveyance direction. In this example, an image is formed by ejecting ink from one row of nozzles of the head 124 at intervals of 1200 dpi in the conveyance direction.

[0025] Next, the principles of ink ejection timing signal generation and ink ejection timing control performed by the timing signal control unit 225 of the print control unit 123 using timing signals output by the conveyance control unit 111 of this embodiment will be described with reference to FIG. 5. In FIG. 5, PA, PB, and PZ are timing charts showing pulse signals representing A-phase, B-phase, and Z-phase signals output by the rotary encoder 115 of the recording device 100 of this embodiment. In this embodiment, the rotary encoder 115, which has 65,536 slits per revolution, is mounted on a roller with a roller diameter of 70 mm. The distance per slit in terms of roller diameter is 70 mm × π ÷ 65,536 ≒ 3,355.58 nm. PA, which indicates A-phase, is a signal that outputs one pulse per slit, and PB, which indicates B-phase, is a signal whose phase is shifted by 90 degrees from PA.

[0026] Furthermore, PZ, which indicates the Z phase, is a signal that is output as a pulse once every time the rotary encoder 115 makes one revolution, that is, every 65,536 PA pulses are input. In the print control of this example, the timing signal control unit 225 generates an ejection timing signal LT every 1,200 dpi in the transport direction based on PA. The head control unit 228 outputs a DATA signal for printing data to the head 124 and a CLK signal for the head 124 to sample the DATA signal, in synchronization with the ejection timing signal LT.

[0027] In this example, the timing signal control unit 225 counts up by 3355.58 nm each time it receives a PA pulse. Each time the count value exceeds 21166.66 nm, it outputs an LT signal. For example, if seven PA pulses are received, the count value becomes 23489.06 nm, exceeding 21166.66 nm. Therefore, the LT signal is output and 21166.66 nm is subtracted from the count value. After the subtraction, if six PA pulses are received, the count value becomes 22455.88 nm. The LT signal is output again and 2166.66 nm is subtracted from the count value. By continuing this process in this manner, the timing signal control unit 225 generates a discharge timing signal based on the timing signal input from the rotary encoder 115 via the conveyance control unit 111. The method for generating the discharge timing signal in this example is merely an example; correction processes may be added to account for roller diameter distortion and the thickness of the continuous sheet M.

[0028] FIG. 5(b) is a timing chart showing a case where the transport speed is faster than that shown in FIG. 5(a). When the transport speed is fast, the pulse interval between PA and PB becomes shorter, and the interval between the ejection timing signals generated based on these PA and PB signals also becomes shorter. This allows printing control to follow the fast transport speed. Similarly, when the transport speed is slow, printing control can be performed to follow the slow transport speed by generating the ejection timing signals based on the PA and PB signals.

[0029] Fig. 6 is a diagram showing the connection of timing signals between the boards of each control unit in the recording device 100. Fig. 6(a) shows the connection between a transport control board 601 that mounts the transport control unit 111 of this example, and multiple print control boards 602 that mount the print control unit 123. The rotary encoder 115 and the transport control board 601 are connected via signal wiring 205 that includes SingleEnd signals indicating A phase, B phase, and Z phase, and GND, and are connected to the transport control unit 111 on the transport control board 601. The signal transmitted is a SingleEnd signal. The transport control board 601 and the print control board 602 located closest to the unwinding unit 112 in the transport direction of the continuous sheet M are connected via signal wiring 206 including LVDS P (Positive) signals and N (Negative) signals indicating the A phase, B phase, and Z phase, and GND, and are connected to the transport control unit 111 on the transport control board 601 and the print control unit 123 on the print control board 602. The print control board 602 is connected to the adjacent print control board 602 via signal wiring 207.

[0030] In the configuration of the recording device 100 of this example, the signal wiring 206 that passes from the unwinding cabinet 101 to the printing cabinet 102 is longer than the signal wiring 207 that connects at the printing cabinet 102. Figure 6(b) shows an example in which, unlike this embodiment, the transport control board 603 and the printing control boards 604 for each color are all directly connected via signal wiring 608. Compared to Figure 6(a), there are many long signal wirings inside the recording device 100.

[0031] As described above, according to this embodiment, in a recording device having multiple print control units, by configuring the print timing signals to be connected sequentially, the wiring length of the entire device can be shortened, the wiring layout can be simplified, and costs can be reduced. [Explanation of symbols]

[0032] 100 Recording device 101 Unwinding cabinet 102 Printing Cabinet 103 Fixing Cabinet 104 Winding cabinet 111 Transport control unit 112 Unwinding section 113 Transport roller 114 Meandering correction section 115 rotary encoder 121 Overall control unit 123 Printing control unit 124 heads 131 Drying control unit 132 Drying fan 143 Transport roller 142 Winding section 201 In-flight network 206 Timing signal wiring 301 Nozzle

Claims

1. a plurality of recording heads each having a plurality of nozzles; a conveying unit that conveys the recording medium; a plurality of print control units that control printing by transferring nozzle data to each print head in synchronization with a timing signal indicating a conveyance state, A recording apparatus characterized in that each print control unit has means for forwarding a received timing signal, and said timing signal is transmitted to said print control units in a sequential manner.

2. 2. The recording apparatus according to claim 1, wherein the timing signal received by the print control unit includes an A-phase signal from a rotary encoder.

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