JPWO2009128351A1 - Image recording device - Google Patents

Abstract

The controller 3 for controlling the line head system 2 and the control from the controller 3 aiming at solving the electromagnetic problem without causing a time difference in transmission of timing signals to each of the plurality of control boards with a simple configuration. A transmission means 4 for transmitting a data signal Sd including image data and a timing signal St for synchronizing ink droplet ejection between the nozzles 21a to the substrate 22 is provided. The transmission means 4 transmits at least the timing signal St. A metal cable 42 and an optical fiber 41 that transmits at least the data signal Sd by daisy chain connecting the controller 3 and the plurality of control boards 22 are provided.

Description

  The present invention relates to an image recording apparatus.

  2. Description of the Related Art Conventionally, an image recording apparatus such as an ink jet printer is of a line head type in which a plurality of recording heads are arranged in parallel and the number of nozzles to be synchronized is increased so as to increase the recording speed and resolution. .

  In this line head type image recording apparatus, a large amount of data flows at high speed on a signal line to a control board for controlling the recording head in response to an increase in recording speed and resolution. Further, particularly in the industrial field, the size of the apparatus is increased due to the fact that the recording medium is generally large and high accuracy is required for printing, and the signal line becomes long.

  At this time, if a metal cable is used as the signal line, a large amount of high-speed data is transmitted over a long distance by the metal conductor forming the metal cable, so the signal waveform becomes dull due to electromagnetic interference, Electromagnetic problems such as external disturbance due to radiation noise from the cable occur.

  Therefore, in order to avoid the electromagnetic problem, a technique using an optical fiber as a signal line has been proposed (see, for example, Patent Document 1).

JP-A-11-28847

  However, the image recording apparatus described in Patent Document 1 includes only one recording head, and does not have a configuration corresponding to a line head system including a plurality of recording heads. When the configuration described in Patent Document 1 is simply applied to a line head type image recording apparatus, a controller 110 that controls the apparatus and a control board 130 that controls each recording head 120, as shown in FIG. Need to be connected by the optical fiber 140, and the number of the optical fiber 140 and the photoelectric conversion element increases, leading to an increase in cost and complexity of the apparatus.

  On the other hand, as shown in FIG. 6, if the optical fiber 140 is arranged in a loop by daisy chain connection, the above-described problems such as cost increase and complication are solved. However, in this configuration, as shown in FIG. 7, the entire signal including the data signal Sd and the timing signal St is sequentially photoelectrically converted and transmitted from the upstream control board 130. A time difference Td occurs in the transmission of the timing signal St to be synchronized to each control board 130.

  The present invention has been made in view of the above circumstances, and has a simple configuration as compared with a case where an optical fiber is simply used as a signal line, and does not cause a time difference in transmission of timing signals to each of a plurality of control boards. An object of the present invention is to provide an image recording apparatus that can solve general problems.

In order to solve the above-mentioned problem, the invention according to claim 1
A line head system having a plurality of recording heads for recording images by discharging droplets from a plurality of nozzles, and a plurality of control boards for controlling the corresponding recording heads; and
A controller for controlling the line head system;
A transmission means for transmitting a data signal including image data and a timing signal for synchronizing droplet discharge between the nozzles from the controller to the control board;
An image recording apparatus comprising:
The transmission means includes at least a metal cable that transmits the timing signal, and an optical communication cable that transmits at least the data signal by daisy chain connecting the controller and the plurality of control boards. .

Invention of Claim 2 is an image recording device of Claim 1, Comprising:
The metal cable connects the controller and the plurality of control boards in a one-to-many manner.

Invention of Claim 3 is an image recording device of Claim 2, Comprising:
The metal cable connects the relay board and the plurality of control boards in a one-to-many manner via a relay board disposed in the middle of the controller and the plurality of control boards. .

Invention of Claim 4 is an image recording device as described in any one of Claims 1-3, Comprising:
A power cable for supplying power to the control board is provided, and the power cable is formed integrally with the metal cable.

  According to the present invention, since the optical communication cable daisy-chains the controller and the plurality of control boards, the number of optical fibers and photoelectric conversion elements to be connected to the plurality of control boards is minimized. be able to. Therefore, a simple configuration can be obtained as compared with a case where an optical fiber is simply used as a signal line. In addition, a large amount of high-speed data signals are transmitted to each control board by optical communication cables, and a relatively low frequency periodic pulse is transmitted to each control board by a metal cable, so that the timing signals are transmitted separately from the data signals. It is possible to prevent obstructions caused by signal waveform dullness and radiation noise from the cable. Therefore, the electromagnetic problem can be solved without causing a time difference in the transmission of the timing signal to each of the plurality of control boards.

1 is a schematic configuration diagram of an image recording apparatus in an embodiment. It is a bottom view of the line head in an embodiment. It is a block diagram which shows the structure of the control board in embodiment. It is a timing chart which shows the example of transmission of the signal to the control board in an embodiment. It is a figure which shows the example which connected the controller and the some control board with the optical fiber simply. It is a figure which shows the example which daisy chain connected the controller and the some control board with the optical fiber. It is a timing chart which shows the example of transmission of the signal to the control board in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an image recording apparatus 1 according to the present invention.

  As shown in FIG. 1, the image recording apparatus 1 includes a line head system 2, a controller 3, and transmission means 4. The image recording apparatus 1 records a predetermined image on a recording medium (not shown) when the controller 3 controls the line head system 2 via the transmission means 4.

  The line head system 2 includes a line head 20 having a plurality of heads 21 and a plurality of control boards 22 for controlling the heads 21.

  As shown in FIG. 2, in the line head 20, a plurality of nozzles 21a arranged linearly on the nozzle surface 21b of each head 21 are arranged in a line in the direction Y, and each nozzle surface 21b forms the same plane downward. Thus, a plurality of heads 21 are provided. In the present embodiment, for convenience, the number of heads 21 is n and the number of nozzles 21a is five. Further, in the following description, each head 21 is distinguished, and the first head 211, the second head 212, the third head 213,..., The n-th head 21n in order from the left end of FIG. And

  The line head 20 records an image on the recording medium by ejecting ink droplets from the nozzle 21a while conveying a recording medium (not shown) to the nozzle surface 21b in the direction X. The line head 20 may be configured by staggering the heads 21 by alternately shifting the positions of the adjacent heads 21 in the direction X in the opposite direction.

  As shown in FIG. 1, the control board 22 is connected to each head 21 one by one and is configured to control the corresponding head 21. In the following description, each control board 22 is distinguished from the upper end of FIG. 1 in order from the first control board 221, the second control board 222, the third control board 223,..., The nth control board 22n. .

  As shown in FIG. 3, the control board 22 includes a light receiving element 23, a light emitting element 24, photoelectric conversion elements 25a and 25b, a data control block 26, a RAM (Random Access Memory) 27, and a waveform generation block 28. .

  The light receiving element 23 and the light emitting element 24 are respectively connected to an optical fiber 41 described later, and receive and emit light to the optical fiber 41. Here, the light receiving element 23 provided on the first control board 221 among the plurality of control boards 22 is connected to the controller 3 via the optical fiber 41 and provided on the remaining second control board 222 to nth control board 22n. The received light receiving elements 23 are connected to the light emitting elements 24 of the first control board 221 to the (n-1) th control board 22n-1 through optical fibers 41 (see FIG. 1). The light emitting element 24 provided on the nth control board 22n is connected to the controller 3 through the optical fiber 41 (see FIG. 1).

  The data control block 26 is connected to the light receiving element 23 via the photoelectric conversion element 25a, is connected to the light emitting element 24 via the photoelectric conversion element 25b, and is also connected to the RAM 27 and the waveform generation block 28. The data control block 26 stores all data signals Sd (described later) received by the light receiving element 23 and subjected to photoelectric conversion by the photoelectric conversion element 25a in the RAM 27, and only the data signal Sd used for driving the corresponding head 21 is stored in the RAM 27. And output to the waveform generation block 28. In addition, all the data signals Sd from which data has been extracted are output to the photoelectric conversion element 25b on the light emitting element 24 side so as to emit light from the light emitting element 24.

  The waveform generation block 28 is connected to the controller 3 through the relay board 43 through a metal cable 42 described later, and is also connected to the head 21 and the data control block 26 corresponding to the control board 22 provided with the waveform generation block 28. (See FIG. 1). This waveform generation block 28 generates a nozzle drive pulse Sn for driving the nozzle 21a from the data signal Sd output from the data control block 26 using a timing signal St described later transmitted from the controller 3 as a trigger. Output to the head 21.

  As shown in FIG. 1, the controller 3 is a personal computer that is connected to the control board 22 of the line head system 2 via the transmission means 4 and controls the line head system 2. The controller 3 transmits to the control board 22 a data signal Sd including image data and a timing signal St for synchronizing ink droplet ejection among all the nozzles 21a, and performs necessary control. In the present embodiment, the controller 3 transmits the timing signal St. The timing signal St is generated from, for example, an encoder signal output from a recording medium conveyance device (not shown). It is common.

  The transmission means 4 includes an optical fiber 41, a metal cable 42, and a relay board 43, and mainly transmits a data signal Sd and a timing signal St from the controller 3 to the control board 22.

  The optical fiber 41 connects the controller 3 and the control board 22 and transmits a data signal Sd mainly including image data. The optical fiber 41 connects an output terminal (not shown) of the controller 3 and the light receiving element 23 of the first control board 221, and each light emitting element of the first control board 221 to the n-1th control board 22n-1. 24 is connected to each light receiving element 23 of the second control board 222 to nth control board 22n, and is wired to connect the light emitting element 24 of the nth control board 22n and the input terminal (not shown) of the controller 3. ing. That is, the optical fiber 41 daisy-chains the controller 3 and all the control boards 22 in a loop shape.

  Thus, since the optical fiber 41 daisy chain connects the controller 3 and all the control boards 22, the number of optical fibers and photoelectric conversion elements for connecting to all the control boards 22 is minimized. The data signal Sd can be transmitted. In addition, the data signal Sd needs to be transmitted at a high speed including a large amount of data in order to cope with high-speed drawing. However, since the data signal Sd is transmitted through the optical fiber 41, the signal waveform is dull, unlike the transmission through the metal conductor. And transmitted without causing troubles due to noise radiated from the cable.

  The metal cable 42 connects the controller 3 and each control board 22 via the relay board 43, and mainly transmits a timing signal St that synchronizes ink droplet ejection between all the nozzles 21a. The metal cable 42 includes a metal cable 42 a that connects the controller 3 and the relay board 43, and n metal cables 42 b that connect the relay board 43 and the control board 22 in a one-to-many manner.

  Each of these metal cables 42a and 42b is formed of a metal conductor. However, a power cable 441 that feeds power from the power source 44 described later to each control board 22 is integrally formed on the metal cable 42b that connects the relay board 43 and each control board 22 by harness processing. In this way, the power cable 441 can be wired simultaneously with the wiring of the metal cable 42b, and the cable wiring work is efficient.

  The timing signal St transmitted by the metal cable 42 is a relatively low frequency periodic pulse. Therefore, even if the signal is not transmitted by the optical fiber 41, the signal waveform is not dulled, and the failure due to the radiation noise from the cable does not occur. In addition, since this timing signal St is transmitted to each control board 22 not by the daisy chain-connected optical fiber 41 but by the metal cable 42, a time difference is received in each control board 22 while being separated from the data signal Sd. It is transmitted without occurring.

  The relay board 43 is disposed in the middle of the controller 3 and the control board 22, and is connected to the controller 3 via the metal cable 42a and to the control board 22 via the metal cable 42b. ing. The relay board 43 includes a buffer (not shown) inside, branches the timing signal St transmitted from the controller 3 without causing a time difference through the buffer, and transmits it to each control board 22. By providing such a relay board 43, it is not necessary to directly connect the controller 3 and each control board 22 in a one-to-many manner, and the metal cable 42 used for the connection can be shortened.

  The relay board 43 is connected to a power supply 44 that supplies power to each control board 22 via a power cable 441. The power cable 441 is branched inside the relay board 43, is subjected to harness processing with a metal conductor that transmits a timing signal St, and is wired to each control board 22 as a metal cable 42b.

  Next, the operation of the image recording apparatus 1 will be described with reference to FIGS. Here, FIG. 4 is a timing chart showing an example of transmission of the data signal Sd and the timing signal St to each control board 22.

  First, the controller 3 transmits all data signals Sd to the first control board 221 through the optical fiber 41, and transmits a timing signal St to the relay board 43 through the metal cable 42a.

  From all the data signals Sd transmitted to the first control board 221, only the data signal Sd (data 01 in FIG. 4) used for driving the first head 211 is extracted by the data control block 26 and output to the waveform generation block 28. At the same time, it is transmitted to the second control board 222 via the light emitting element 24. Then, in the second control board 222 to the nth control board 22n, as in the first control board 221, only the data signal Sd (shaded part in FIG. 4) used for driving the corresponding head 21 is sequentially extracted. It is output to the waveform generation block 28. At this time, although the data signal Sd transmitted to each control board 22 causes a delay in the transmission order, both are transmitted earlier than the timing signal St. Therefore, the delay is caused by the generation of the nozzle drive pulse Sn by the waveform generation block 28. Is not reflected.

  On the other hand, the timing signal St transmitted to the relay board 43 is branched by the relay board 43 and transmitted to the waveform generation block 28 of each control board 22 through the metal cable 42b without causing a time difference.

  The waveform generation block 28 of each control board 22 generates a nozzle drive pulse Sn for driving the nozzle 21a from the data signal Sd output from the data control block 26 using the timing signal St transmitted from the relay board 43 as a trigger. To the corresponding head 21. Then, the head 21 discharges ink droplets from the nozzles 21a to the recording medium in accordance with the input nozzle driving pulse Sn, and records a predetermined image.

  As described above, according to the image recording apparatus 1 in the present embodiment, since the number of optical fibers and photoelectric conversion elements for connection to all the control boards 22 can be minimized, the light can be simply used. Compared to the case shown in FIG. 5 in which a fiber is used as a signal line, the configuration can be simplified. Further, while transmitting the timing signal St separately from the data signal Sd, it is possible to prevent the signal waveform from becoming dull and obstructing due to radiation noise from the cable, etc., so that there is a time difference in transmission of the timing signal St to each control board 22. Without being able to solve the electromagnetic problem.

  In the above-described embodiment, the head 21 and the control board 22 are made to correspond one-to-one. However, for example, one control board 22 may be made to correspond to a plurality of heads 21.

  In addition, regarding other points, the present invention is not limited to the above-described embodiment, and it is needless to say that it can be appropriately changed.

DESCRIPTION OF SYMBOLS 1 Image recording apparatus 2 Line head system 3 Controller 4 Transmission means 20 Line head 21 Head (recording head)
21a Nozzle 22 Control board 41 Optical fiber (optical communication cable)
42 Metal cable 43 Relay board 441 Power cable Sd Data signal St Timing signal

Claims (4)

A line head system having a plurality of recording heads for recording images by discharging droplets from a plurality of nozzles, and a plurality of control boards for controlling the corresponding recording heads; and
A controller for controlling the line head system;
A transmission means for transmitting a data signal including image data and a timing signal for synchronizing droplet discharge between the nozzles from the controller to the control board;
An image recording apparatus comprising:
The transmission means includes at least a metal cable that transmits the timing signal, and an optical communication cable that transmits at least the data signal by daisy chain connecting the controller and the plurality of control boards. Image recording device.   The image recording apparatus according to claim 1, wherein the metal cable connects the controller and the plurality of control boards in a one-to-many manner.   The metal cable connects the relay board and the plurality of control boards in a one-to-many manner via a relay board disposed in the middle of the controller and the plurality of control boards. The image recording apparatus according to claim 2.   The image recording according to claim 1, further comprising a power cable for supplying power to the control board, wherein the power cable is formed integrally with the metal cable. apparatus.