JP2021035748A - Image formation apparatus and driving method of carriage - Google Patents

Abstract

To provide an image formation apparatus which can properly form an image by using a plurality of carriages and a driving method of the carriage.SOLUTION: An image formation apparatus comprises: a plurality of carriages on which image formation operation parts for performing operations related to formation of an image to a recording medium are respectively mounted; a support member which supports the plurality of carriages so as to be reciprocally movable along a prescribed movement path; a driving unit which independently drives each of the plurality of carriages; and driving control means which controls the driving unit. The movement path includes a first region and a second region that is on an end side of the movement path with respect to the first region. The driving control means controls the driving unit such that an interval of a pair of carriages in a case where the pair of any adjacent carriages is in the first region becomes larger than an interval of the pair of carriages in a case where the pair of carriages is in the second region when there are at least two or more moving carriages.SELECTED DRAWING: Figure 7

Description

The present invention relates to an image forming apparatus and a method for driving a carriage.

Conventionally, an image forming apparatus has been known in which ink is ejected from a nozzle provided in an ink ejection head to a recording medium to form an image. This image forming apparatus includes a support member that supports a carriage equipped with an ink ejection head so as to be reciprocally movable along a predetermined movement path, and while moving the carriage along the movement path, a nozzle of the ink ejection head. Some images are formed by ejecting ink onto a recording medium at an appropriate timing. Further, there is known a technique of attaching a plurality of carriages to a support member and ejecting ink from a recording head of each carriage while moving two or more carriages at the same time (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-40083

However, if the number of carriages to be moved at the same time is increased, the support member bends depending on the weight of the carriage and the strength of the support member, the distance between the carriage and the recording medium becomes short, the ink landing position shifts, or the carriage becomes the recording medium. There is a problem of contact with the carriage. Therefore, the above-mentioned conventional technique has a problem that an image cannot be properly formed due to the bending of the support member.

An object of the present invention is to provide an image forming apparatus capable of appropriately forming an image using a plurality of carriages and a method for driving the carriage.

In order to achieve the above object, the invention of the image forming apparatus according to claim 1 is
A mounting member having a mounting surface on which the recording medium is mounted, and
A plurality of carriages each equipped with an image forming operation unit that performs an operation related to image formation on a recording medium on the mounting surface described above, and
A support member that supports the plurality of carriages so as to be reciprocally movable along a predetermined movement path passing over the above-mentioned mounting surface.
A drive unit that independently moves each of the plurality of carriages along the movement path,
A drive control means for controlling the drive unit and
With
The movement path includes a first region and a second region on the end side of the movement path with respect to the first region.
The drive control means is used when there are at least two moving carriages among the plurality of carriages, and when any adjacent pair of carriages among the plurality of carriages are in the first region. The driving unit is controlled so that the distance between the pair of carriages is larger than the distance between the pair of carriages when the pair of carriages is in the second region.

The invention according to claim 2 is the image forming apparatus according to claim 1.
The second region is provided on both sides of the first region.

The invention according to claim 3 is the image forming apparatus according to claim 1 or 2.
The drive control means has a predetermined upper limit in which the number of carriages in a predetermined limiting area inside the first region of the plurality of carriages is less than the number of carriages included in the plurality of carriages. It is characterized in that the drive unit is controlled so that the number is less than or equal to the number.

The invention according to claim 4 is the image forming apparatus according to any one of claims 1 to 3.
The drive control means is characterized in that the movement start timing of the next carriage is determined based on the elapsed time after starting the movement of one of the plurality of carriages.

The invention according to claim 5 is the image forming apparatus according to any one of claims 1 to 3.
A position information acquisition means for acquiring position information relating to a position in the movement path of each of the plurality of carriages is provided.
The drive control means is characterized in that after starting the movement of one of the plurality of carriages, the movement start timing of the next carriage is determined based on the position information related to the position of the one carriage. There is.

The invention according to claim 6 is the image forming apparatus according to any one of claims 1 to 5.
The image forming operation unit performs the operation when the carriage on which the image forming operation unit is mounted is within a predetermined image forming region in the movement path.
The first region is characterized by including at least a part of the image forming region.

The invention according to claim 7 is the image forming apparatus according to claim 6.
The first region is characterized in that it is set inside from both ends of the image forming region.

The invention according to claim 8 is the image forming apparatus according to claim 6 or 7.
The drive control means is characterized in that the drive unit is controlled so that two or more carriages among the plurality of carriages are simultaneously located in the image forming region at any timing.

The invention according to claim 9 is the image forming apparatus according to any one of claims 6 to 8.
At least a part of the plurality of carriages is equipped with the image forming operation unit having an ink ejection head for ejecting ink to the recording medium.
The image forming apparatus is characterized by comprising a ejection control means for ejecting ink by the ink ejection head at a timing corresponding to the movement of the carriage.

The invention according to claim 10 is the image forming apparatus according to claim 9.
A cleaning unit for cleaning the ink ejection head of the carriage at a predetermined cleaning position on the outside of the image forming region is provided.
In the drive control means, when at least one of the plurality of carriages is located in the first region, at least one of the plurality of carriages on which the ink ejection head is mounted is in the cleaning position. It is characterized in that the drive unit is controlled so as to be located.

The invention according to claim 11 is the image forming apparatus according to claim 9 or 10.
An ink receiving unit that receives ink ejected from the ink ejection head of the carriage at a predetermined ink receiving position on the outside of the image forming region is provided.
In the drive control means, when at least one of the plurality of carriages is located in the first region, at least one of the plurality of carriages on which the ink ejection head is mounted is the ink receiving position. It is characterized in that the drive unit is controlled so as to be located at.

The invention according to claim 12 is the image forming apparatus according to any one of claims 9 to 11.
At least one of the plurality of carriages is equipped with the image forming operation unit having a plurality of first ink ejection heads for ejecting inks of a plurality of basic colors.
At least one of the plurality of carriages is equipped with the image forming operation unit having a second ink ejection head for ejecting ink of an auxiliary color other than the plurality of basic colors.
The ejection control means includes a first mode in which ink is ejected by the first ink ejection head and the second ink ejection head, and the second mode in which ink is ejected by the first ink ejection head. It is characterized in that the ink is ejected by the ink ejection head in one of the modes selected from the second mode in which the ink is not ejected by the ink ejection head.

The invention according to claim 13 is the image forming apparatus according to any one of claims 9 to 12.
Each of the two or more carriages among the plurality of carriages is equipped with the image forming operation unit having the ink ejection head for ejecting ink of the same color.
The ejection control means is characterized in that the ink ejected from the ink ejection heads of the two or more carriages is superimposed on the recording medium and landed on the recording medium on the above-mentioned mounting surface. ..

The invention according to claim 14 is the image forming apparatus according to any one of claims 9 to 13.
Each of at least two carriages among the plurality of carriages is equipped with the image forming operation unit having the ink ejection head for ejecting ink of the same color.
The ejection control means ejects ink that has not been ejected from the ink ejection head of one of the at least two carriages to the recording medium on the above-mentioned mounting surface, among the at least two carriages. It is characterized in that it is complemented by the ink ejected from the ink ejection head of any one of the carriages.

The invention according to claim 15 is the image forming apparatus according to any one of claims 9 to 14.
Each of at least two carriages among the plurality of carriages is equipped with the image forming operation unit having the ink ejection head for ejecting ink of the same color.
Each of the ink ejection heads is provided with a plurality of nozzles for ejecting ink at predetermined intervals in an arrangement direction orthogonal to the movement direction of the carriage along the movement path.
The ink ejection heads of each of the at least two carriages are characterized in that the nozzle positions in the arrangement direction are arranged in different positional relationships from each other.

The invention according to claim 16 is the image forming apparatus according to any one of claims 9 to 15.
The ink ejection head ejects ink that is cured by irradiating with ultraviolet rays.
At least a part of the plurality of carriages is characterized in that the image forming operation unit having an ultraviolet irradiation unit that irradiates the ink ejected on the recording medium with ultraviolet rays is mounted.

The invention according to claim 17 is the image forming apparatus according to any one of claims 1 to 16.
At least a part of the plurality of carriages is characterized in that the image forming operation unit having a functional liquid application unit that applies a predetermined functional liquid to the recording medium is mounted.

The invention according to claim 18 is the image forming apparatus according to any one of claims 1 to 17.
It is characterized in that a transport unit for transporting the recording medium in the transport direction is provided by moving the pre-described placement surface of the pre-described placement member in a transport direction that intersects the movement direction of the carriage along the movement path. ..

Further, in order to achieve the above object, the invention of the carriage driving method according to claim 19.
A plurality of carriages each equipped with a mounting member having a mounting surface on which the recording medium is mounted, an image forming operation unit that performs an operation related to image formation on the recording medium on the previously described mounting surface, and the above. A support member that reciprocally supports a plurality of carriages along a predetermined movement path passing over the above-mentioned mounting surface, and a drive unit that independently moves each of the plurality of carriages along the movement path. It is a method of driving a carriage in an image forming apparatus equipped with.
The movement path includes a first region and a second region on the end side of the movement path with respect to the first region.
The driving method is the case where there are at least two moving carriages among the plurality of carriages and any adjacent pair of carriages among the plurality of carriages is in the first region. It is characterized by including a drive control step for controlling the drive unit so that the distance between the pair of carriages is larger than the distance between the pair of carriages when the pair of carriages are in the second region.

According to the present invention, there is an effect that an image can be appropriately formed by using a plurality of carriages.

It is a figure which shows the schematic structure of the inkjet recording apparatus. It is a figure which shows the structure of a carriage. It is a figure which shows the arrangement of the ink ejection head in a carriage. It is a block diagram which shows the main functional structure of an inkjet recording apparatus. It is a figure which shows the operation of the carriage in the 1st mode. It is a figure explaining the 1st region and the 2nd region in detail. It is a figure explaining the driving method of a carriage. It is a flowchart which shows the control procedure of an image formation process. It is a figure which shows the arrangement of the ink ejection head in the carriage which concerns on a comparative example. It is a figure explaining the printing process in the comparative example and the example of the configuration of this embodiment. It is a figure explaining the driving method of the carriage which concerns on modification 1. FIG. It is a flowchart which shows the control procedure by the control part of the image formation processing which concerns on modification 2. It is a figure which shows the arrangement of the ink ejection head in the carriage which concerns on modification 3. It is a figure explaining the complementary ejection of ink in the modification 3. It is a figure which shows the arrangement of the ink ejection head in the carriage which concerns on modification 4. It is a figure which shows the structure of the carriage which concerns on modification 5.

Hereinafter, embodiments relating to the image forming apparatus and the carriage driving method of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an inkjet recording device 1 according to an embodiment of the present invention.
The inkjet recording device 1 (image forming device) includes a transport unit 10, a recording unit 20, a control unit 30 (see FIG. 4), and the like.

The transport unit 10 includes a drive roller 11, a driven roller 12, a transport belt 13 (mounting member), a transport motor 14, and the like.
The drive roller 11 rotates about a rotation shaft by being driven by the transfer motor 14. The transport belt 13 is a ring-shaped belt whose inside is supported by the drive roller 11 and the driven roller 12, and moves around as the drive roller 11 rotates. The driven roller 12 rotates about a rotation axis parallel to the rotation axis of the drive roller 11 as the conveyor belt 13 orbits moves. The outer peripheral surface of the transport belt 13 constitutes a mounting surface 13a on which the recording medium P is mounted. As the transport belt 13, a material that flexibly bends at the contact surface with the drive roller 11 and the driven roller 12 and reliably supports the recording medium P is used. For example, a resin belt such as rubber or a belt made of resin such as rubber is used. A steel belt or the like can be used. Since the transport belt 13 has a material and / or a structure in which the recording medium P is attracted, the recording medium P can be more stably mounted on the mounting surface 13a.

The transfer motor 14 rotates the drive roller 11 at a rotation speed according to a control signal from the control unit 30. The transport unit 10 rotates the transport belt 13 at a speed corresponding to the rotation speed of the drive roller 11 in a state where the recording medium P is mounted on the mounting surface 13a of the transport belt 13 to move the recording medium P. The transport operation of transporting the transport belt 13 in the moving direction (transportation direction, sub-scanning direction) is performed. In other words, the transport unit 10 transports the recording medium P in the transport direction by moving the mounting surface 13a of the transport belt 13 in the transport direction. Further, the transport unit 10 includes a rotary encoder (not shown) that detects the rotation angle of the drive roller 11 and transmits the detection result to the control unit 30.

In FIG. 1, an example in which the recording medium P is a sheet of paper is drawn. However, the recording medium P is not limited to sheet paper, and the roll paper or the like that is unwound (unrolled) from the roll (recording medium unwinding portion) around which the recording medium P is wound and supplied onto the transport belt 13. It may be. Further, as the recording medium P, in addition to paper, various materials such as cloth and sheet-shaped resin capable of fixing the ink ejected to the surface can be used.
The size of the recording medium P is not particularly limited, but for example, a large-sized recording medium P having a width of about 2 m in the main scanning direction orthogonal to the sub-scanning direction can also be used. Therefore, the transport unit 10 of the present embodiment is configured to be capable of transporting a large recording medium P having a width of about 2 m in the main scanning direction. The transport unit 10 may transport the recording medium P having a width smaller than 2 m in the main scanning direction. Further, the transport unit 10 may be configured to be capable of transporting a recording medium P having a width larger than 2 m (for example, about 4 m) in the main scanning direction, and the main scan of the transportable recording medium P. The maximum width in the direction may be smaller than 2 m.

The recording unit 20 includes a first carriage 21A and a second carriage 21B (hereinafter, when any one of them is referred to, the carriage 21 is referred to) on which the ink ejection head 213 for ejecting ink is mounted. A main scanning rail 22 to which the first carriage 21A and the second carriage 21B are attached, a cleaning unit 23 (cleaning unit), a capping unit 24 (ink receiving unit), and the like are provided.
The recording unit 20 ejects ink from the ink ejection head 213 of each carriage 21 to the recording medium P on the mounting surface 13a while moving the first carriage 21A and the second carriage 21B along the main scanning rail 22. Performs the main scanning operation.
Further, the inkjet recording device 1 alternately executes the above-mentioned main scanning operation and the sub-scanning operation in which the transport unit 10 transports the recording medium P in the sub-scanning direction by a predetermined distance to obtain an image on the recording medium P. To form.

The main scanning rail 22 includes a support member 221 extending in the main scanning direction.
The support member 221 supports the first carriage 21A and the second carriage 21B so as to be reciprocally movable along a one-dimensional movement path that passes over the mounting surface 13a and is parallel to the main scanning direction. The support member 221 of the present embodiment is a prismatic member, but is not limited to this shape. A pair of linear guides 222, a linear motor magnet 223, and a linear scale 224 are provided on the mounting surface of the support member 221 to which the carriage 21 is mounted (the side surface facing the transport direction in FIG. 1).

The linear guide 222 is a rail for guiding the carriage 21 in the main scanning direction. The linear guide 222 has a groove extending in the main scanning direction. The carriage 21 can slide along the linear guide 222 in a state where a mounting member (not shown) provided on the carriage 21 is fitted in the groove.

The linear motor magnet 223 is a linear magnet for moving each carriage 21 by the operation of the linear motor 215 (driving unit) (see FIG. 2) mounted on each carriage 21, and is used as a stator of the linear motor. Equivalent to. Specifically, the linear motor magnet 223 is a magnet array in which N poles and S poles are repeatedly arranged in the main scanning direction. In the present embodiment, the magnetic poles at each position of the linear motor magnet 223 are fixed, and the carriage 21 moves by changing the magnetic poles on the linear motor 215 side of the carriage 21.

The linear scale 224 is a member extending in the main scanning direction, and a scale read by a linear encoder 216 (see FIG. 2) mounted on each carriage 21 is engraved on the surface.

Support columns 225 that support the support member 221 from below in the vertical direction are provided at both ends of the support member 221 in the main scanning direction. In the region between the pair of columns 225, a member for supporting the support member 221 is not provided, and the support member 221 supports the carriage 21 by its rigidity.

FIG. 2 is a diagram showing the configuration of the carriage 21.
The carriage 21 includes a housing 211, an image forming operation unit 212 housed inside the housing 211, a head drive board 214, a linear motor 215 (drive unit), a linear encoder 216, and the like. In FIG. 2, for convenience of explanation, a part of the housing 211 is drawn transparently to show the internal structure of the housing 211.

The image forming operation unit 212 has eight ink ejection heads 213, and operates related to the formation of an image on the recording medium P on the mounting surface 13a of the transport belt 13 (here, the ink ejected by the ink ejection head 213). Discharge operation) is performed. The image forming operation unit 212 performs the above operation when the carriage 21 on which the image forming operation unit 212 is mounted is within a predetermined image forming region Rp in the movement path. The image forming region Rp is set in a region facing the mounting surface 13a or a region excluding the vicinity of both ends of the region.

Each of the eight ink ejection heads 213 has a nozzle surface on which a plurality of nozzles for ejecting ink are formed, and the nozzle surface is exposed from an opening provided in the bottom surface 211a of the housing 211. Is fixed to the housing 211. Each ink ejection head 213 is attached at a position where the distance between the nozzle surface during the main scanning operation and the mounting surface 13a of the transport belt 13 is a predetermined distance (for example, about 2 mm).

FIG. 3 is a diagram showing the arrangement of the ink ejection head 213 on the carriage 21. FIG. 3 is a diagram showing the bottom surfaces 211a of the first carriage 21A and the second carriage 21B as viewed from the mounting surface 13a side of the transport belt 13.

The first carriage 21A is equipped with two ink ejection heads 213Y, 213M, 213C, and 213K that eject Y (yellow), M (magenta), C (cyan), and K (black) inks, respectively. There is. Y, M, and C are the three primary colors used for color expression by subtractive color mixing, and K is black, which is difficult to obtain in practice only by superimposing the three primary colors. These four colors are called basic colors (process colors) and are a combination of basic colors used for recording images by various image forming devices such as an inkjet recording device. The ink ejection heads 213Y, 213M, 213C, and 213K correspond to the first ink ejection head.

The second carriage 21B is equipped with two ink ejection heads 213LM, 213LC, 213O, and 213G for ejecting LM (light magenta), LC (light cyan), O (orange), and G (gray) inks, respectively. ing. Each of the LM, LC, O, and G colors is an auxiliary color having a hue different from that of the basic color. Complementary colors are used to express colors different from the combination of basic colors by mixing with at least one of Y, M, and C. The ink ejection heads 213LM, 213LC, 213O, and 213G correspond to the second ink ejection head.

Each ink ejection head 213 is provided with two rows of nozzles. Each nozzle row is composed of a plurality of nozzles N that are one-dimensionally arranged at equal intervals in the sub-scanning direction (arrangement direction). The two nozzle rows have a positional relationship in which the position of the nozzle N in the sub-scanning direction is deviated from each other by 1/2 of the arrangement pitch of the nozzle N. However, the number of nozzle rows is not limited to two, and may be one or three or more.
The mechanism for ejecting ink from each nozzle N of the ink ejection head 213 is not particularly limited, but in the present embodiment, a piezoelectric element such as a piezo element is provided on the wall surface of the pressure chamber communicating with the nozzle N, and the piezoelectric element (hence, therefore). A mechanism is used in which the ink is ejected from the nozzle N by deforming the pressure chamber) to cause a pressure fluctuation in the ink in the pressure chamber.

The positions of the two ink ejection heads 213 of the same color are shifted in the main scanning direction and viewed from the main scanning direction so that the arrangement range of the nozzles N in the sub scanning direction is continuous over the width W in FIG. The ends are arranged in an overlapping positional relationship. Further, the eight ink ejection heads 213 mounted on one ink ejection head 213 are arranged in a houndstooth pattern.

Returning to FIG. 2, the head drive substrate 214 is a substrate on which a head control circuit that outputs a drive signal for driving the piezoelectric element to the ink ejection head 213 is mounted based on the image data of the recorded image. The head drive board 214 is electrically connected to the ink ejection head 213 via wiring (not shown), and the ink ejection head 213 is connected to the ink ejection head 213 from the head control circuit at an appropriate timing according to the position of the carriage 21 in the main scanning operation. Outputs a drive signal to. FIG. 2 shows an example in which one head drive substrate 214 is provided for eight ink ejection heads 213, but the present invention is not limited to this, and each ink ejection head 213 or a predetermined number of ink ejection heads are ejected. A head drive board 214 may be provided for each head 213.

The linear motor 215 is an electromagnetic motor that serves as a drive source for moving the carriage 21 along the linear guide 222 and the linear motor magnet 223. The specific configuration of the linear motor 215 is not particularly limited, but for example, a configuration in which the magnetic pole of the electromagnetic coil is changed by controlling the current with respect to the electromagnetic coil can be used. As described above, in the present embodiment, the magnetic pole of the linear motor magnet 223 is fixed, and the carriage 21 is driven by changing the magnetic pole of the carriage 21 on the linear motor 215 side. As a result, each carriage 21 can be moved independently. That is, the timings of the movement start and movement end of each carriage 21 can be independently determined, and each carriage can be driven so that there are at least two or more moving carriages at least at a partial timing. You can do it. A drive unit is composed of a plurality of linear motors 215 included in a plurality of (here, two) carriages 21.

The linear encoder 216 reads the scale of the linear scale 224 when the carriage 21 moves, and outputs a signal indicating the position of the carriage 21 to the control unit 30 according to the reading result. As the linear encoder 216, for example, a type in which the scale is read by an optical sensor is used, but the linear encoder 216 is not limited to this. The position of the carriage 21 can be the position of a representative point of the carriage 21. This representative point can be any position on the carriage 21 as long as it is common to each carriage 21, and can be, for example, a position where the optical sensor of the linear encoder 216 is provided.

Returning to FIG. 1, the cleaning unit 23 is provided at a position facing the nozzle surface of the ink ejection head 213 when the carriage 21 moves to a predetermined cleaning position. The cleaning unit 23 performs a cleaning operation for cleaning the nozzle surface of the carriage 21 that has moved to the cleaning position. The cleaning position is defined as a position outside the image forming region Rp and near the end of one side (right side in FIG. 1) of the movement path of the carriage 21.

The cleaning unit 23 wipes and removes ink and other impurities adhering to the nozzle surface by moving the wiping member along the nozzle surface in a state where the wiping member (not shown) is in contact with the nozzle surface. .. As the wiping member, a blade made of an elastically deformable member such as urethane or rubber can be used. However, the material of the wiping member is not limited to this, and a porous member (porous) made of a resin such as polyolefin, various cloths, sponges, etc. may be used. FIG. 1 shows an example in which one cleaning unit 23 is provided for each of the first carriage 21A and the second carriage 21B, but one cleaning unit 23 is shared by a plurality of carriages 21. You may.

The capping unit 24 is provided at a position facing the nozzle surface of the ink ejection head 213 when the carriage 21 moves to a predetermined ink receiving position. The capping unit 24 receives and stores the ink ejected by the ink ejection operation (flushing) from the nozzle N of the ink ejection head 213. Further, the capping unit 24 covers the nozzle surface of the ink ejection head 213 to prevent the nozzle surface from drying after the ejection disposal operation is completed. By performing the discharge operation, foreign matter and air bubbles in the nozzle N can be discharged to the outside together with the ink. In addition to the normal ink ejection operation from the nozzle N, the ejection discharge operation may be an operation (pressurization purge) in which pressure is applied to the ink in the nozzle N from the outside to forcibly discharge the ink from the nozzle N. it can. The ink receiving position is defined as a position outside the image forming region Rp and near the end of the other side (left side in FIG. 1) of the movement path of the carriage 21.
FIG. 1 shows an example in which one capping unit 24 is provided for each of the first carriage 21A and the second carriage 21B, but one capping unit 24 is shared by a plurality of carriages 21. You may.

FIG. 4 is a block diagram showing a main functional configuration of the inkjet recording device 1.
The inkjet recording device 1 includes a transfer motor 14 provided in the transfer unit 10, an ink ejection head 213 provided in the carriage 21, a head drive board 214, a linear motor 215 and a linear encoder 216, a cleaning unit 23, and a control unit. 30 (drive control means, position information acquisition means, discharge control means), an operation display unit 41, a communication unit 42, a bus 43, and the like are provided. In the following, description of the components already described will be omitted.

The control unit 30 includes a CPU 31 (Central Processing Unit), a RAM 32 (Random Access Memory), a ROM 33 (Read Only Memory), and a storage unit 34.

The CPU 31 reads out various control programs and setting data stored in the ROM 33, stores them in the RAM 32, executes the programs, and performs various arithmetic processes.

The RAM 32 provides a working memory space to the CPU 31 and stores temporary data. The RAM 32 may include a non-volatile memory.

The ROM 33 stores various control programs, setting data, and the like executed by the CPU 31. Instead of the ROM 33, a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

The storage unit 34 stores a print job (image formation command) input from an external device via the communication unit 42 and image data related to the print job. As the storage unit 34, for example, an HDD (Hard Disk Drive) may be used, or a DRAM (Dynamic Random Access Memory) or the like may be used in combination.

The control unit 30 having such a configuration controls the overall operation of the inkjet recording device 1 by the CPU 31 executing a predetermined process according to the program.
For example, the control unit 30 sends a control signal to the transfer motor 14 at an appropriate timing to operate the transfer motor 14 to rotate the drive roller 11, and the transfer unit 10 sends the recording medium P at a predetermined speed to a predetermined distance. Transport.
Further, the control unit 30 as the position information acquisition means acquires the position information related to the position in the movement path of each carriage 21 by the signal received from the linear encoder 216.
Further, the control unit 30 as the ejection control means sends the image data and the control signal to the head drive substrate 214 to drive the ink ejection head 213 from the head drive substrate 214 at an appropriate timing according to the position of the carriage 21. A signal is output, and ink is ejected from the nozzle N of the ink ejection head 213.
Further, the control unit 30 as the drive control means sends a control signal to the linear motor 215 to operate it, and starts the movement operation of each carriage 21 in the main scanning direction at an appropriate timing.
Further, the control unit 30 sends a control signal to the cleaning unit 23 at the timing when the carriage 21 moves to the cleaning position, and causes the cleaning unit 23 to perform the cleaning operation.

The operation display unit 41 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as an operation key and a touch panel arranged on the screen of the display device. The operation display unit 41 displays various information on the display device, converts the user's input operation to the input device into an operation signal, and outputs the operation signal to the control unit 30.

The communication unit 42 transmits / receives data to / from an external device according to a predetermined communication standard. The communication unit 42 includes a connection terminal according to the communication standard to be used, driver hardware (network card) related to the communication connection, and the like.

The bus 43 is a path for transmitting and receiving signals between the control unit 30 and other configurations.

Next, the image forming operation by the inkjet recording device 1 will be described.
As described above, in the inkjet recording device 1, the recording unit 20 moves the carriage 21 along the main scanning rail 22 while ejecting ink from the ink ejection head 213 to the recording medium P, and the conveying unit 10 records. An image is formed on the recording medium P by alternately executing the sub-scanning operation of transporting the medium P in the sub-scanning direction by a predetermined distance.

Further, the control unit 30 ejects each ink in one of the modes selected from the first mode in which the image is formed only by the basic colors and the second mode in which the image is formed by the combination of the basic colors and the auxiliary colors. Ink is ejected by the head 213 to form an image on the recording medium P. Therefore, in the first mode, the first carriage 21A and the second carriage 21B are used to form the image, and in the second mode, only the first carriage 21A is used to form the image. The mode is selected based on, for example, an input operation on the operation display unit 41 by the user. In the following, the operation of the first mode using two carriages 21 will be described in detail.

FIG. 5 is a diagram showing the operation of the carriage 21 in the first mode.
As shown in FIG. 5, in the first mode, the first carriage 21A moves along the support member 221 of the main scanning rail 22 to perform the main scanning operation, and the second carriage 21B The move is started. Therefore, during a part of the image forming operation, the first carriage 21A and the second carriage 21B move in the main scanning direction at the same time. In other words, the control unit 30 controls the linear motor 215 of each carriage 21 so that there are at least two or more moving carriages during a part of the image forming operation.

However, as described above, in the region between the pair of columns 225, the member that supports the support member 221 is not provided, and the support member 221 is subjected to an excessive load in the vertical direction at a position away from the columns 225. And bending will occur.
In recent years, the number of ink ejection heads 213 mounted on the carriage 21 tends to increase and the weight of the carriage 21 tends to increase due to the demand for image formation with higher throughput and higher definition of color tone expression. Further, in particular, in the inkjet recording device 1 for textiles and home fabrics, there is a demand for lengthening the support member 221 of the main scanning rail 22 in order to increase the image formation width. Both the increase in the weight of the carriage 21 and the increase in the length of the support member 221 tend to cause the support member 221 to bend easily, and in recent years, the bending of the support member 221 has become a particular problem.

On the other hand, in the present embodiment, in order to suppress the bending of the support member 221, the distance between the carriages 21 when the adjacent carriages 21 are in the first region A1 in the movement path is the second regions A2 and A3. The carriage 21 is driven so as to be larger than the distance between the carriages 21 in the case of. Here, the second region A2 is a region on one end side of the movement path with respect to the first region A1, and the second region A3 is the other region of the movement path with respect to the first region A1. The area on the edge side of.
Further, in the present embodiment, the carriage 21 is driven so that the number of carriages 21 in the predetermined limiting region R1 inside the both ends of the first region A1 is equal to or less than the predetermined upper limit number. The above upper limit is set to a number less than the number of carriages 21 included in the inkjet recording device 1. Since the number of carriages 21 is two in the present embodiment, the upper limit is set to one. That is, the carriage 21 is driven so that the number of carriages in the restricted area R1 is one or less at an arbitrary timing.

FIG. 6 is a diagram for explaining the first region A1 and the second regions A2 and A3 in detail.
The thick line in FIG. 6 indicates a region such as the first region A1, the second region A2, and A3. Further, among the circle marks at both ends of each line, the black circles indicate that the area includes the position of the end, and the white circles indicate that the area does not include the position of the end. Further, the position pr1 is the position of the boundary between the first region A1 and the second region A2 in the main scanning direction, and the position pr2 is the position of the boundary between the first region A1 and the second region A2 in the main scanning direction. It is the position of the boundary with.
As shown in FIG. 6, the first region A1 is a region including the positions pr1 and pr2 and the region inside the positions pr1 and pr2. Further, the second region A2 does not include the position pr1 and is a region outside the position pr1. Further, the second region A3 does not include the position pr2 and is a region outside the position pr2. The movement path Rmv of the carriage 21 includes a first region A1, a second region A2, and A3.
Further, the above-mentioned restricted region R1 does not include the positions pr1 and pr2, but includes the region inside the positions pr1 and pr2. Therefore, the restricted region R1 is a region obtained by excluding the positions pr1 and pr2 at both ends of the first region A1 from the first region A1. In the following, the region on one end side of the movement path Rmv excluding the restricted region R1 will be referred to as an unrestricted region R2, and the region on the other end side will be referred to as an unrestricted region R3.

The limiting area R1 is a weight limiting area in which the weight applied to the support member 221 is limited. The limiting region R1 is a region in which the support member 221 bends when an upper limit number or more of the carriages 21 are located in the region, and the image quality of the recorded image deteriorates to a predetermined standard or less. This deterioration in image quality is caused by the fact that the support member 221 bends, so that the distance between the nozzle surface of the ink ejection head 213 and the recording medium P becomes small, and the landing position of the ink ejected from the nozzle N deviates from the desired position. Occurs. Further, depending on the amount of bending of the support member 221, the nozzle surface may come into contact with the recording medium P. The permissible value of the amount of bending of the support member 221 is, for example, about ± 100 μm.
In the present embodiment, by suppressing the number of carriages 21 located in the limited region R1 to the upper limit or less, the occurrence of bending of the support member 221 is effectively suppressed.

The first region A1 and the restricted region R1 correspond to a part of the image forming region Rp. In the present embodiment, the first region A1 and the restricted region R1 are set inside the image forming region Rp from both ends. Therefore, even when one carriage 21 is in the restricted region R1, the other carriage 21 can be located in an area outside the restricted region R1 of the image forming region Rp. At this timing, ink can be ejected simultaneously and in parallel from the ink ejection heads 213 of the two carriages 21 to the same recording medium P. Hereinafter, the period during which the ink ejection heads 213 of the two carriages 21 eject ink in parallel is also referred to as a “parallel ejection period”. The longer the parallel ejection period is, the shorter the image formation time can be. Therefore, the control unit 30 keeps the two carriages 21 from entering the restriction region R1 and linearly arranges the two carriages 21 so that the two carriages 21 are simultaneously located in the image forming region Rp at any timing. Controls the motor 215.

Further, the non-restricted regions R2 and R3 are regions in which the support member 221 is fixed to the structure of the inkjet recording device 1 (here, the support column 225) and a region in the vicinity of the fixed region, which is the upper limit described above. This is a region in which the support member 221 does not undergo an amount of deflection that affects the image quality even if a number or more of the carriages 21 are located.

Next, the driving method of the two carriages 21 will be described in detail.
FIG. 7 is a diagram illustrating a method of driving the carriage 21.
FIG. 7 shows the time change of the positions of the first carriage 21A and the second carriage 21B. In the following, for convenience, the route from the left end to the right end of FIG. 1 will be referred to as an outward route, and the route from the right end to the left end will be referred to as a return route.
The vertical axis of FIG. 7 represents the position in the main scanning direction when the left end of FIG. 1 is the origin of the movement path of the carriage 21. The position pp1 is the left end position of the image forming region Rp, and the position pp2 is the right end position of the image forming region Rp. In FIG. 7, diagonal lines are provided in the image forming region Rp.

As shown in FIG. 7, at the time when the image forming operation is started (origin of the time axis), the first carriage 21A and the second carriage 21B are located at the standby positions of the second region A2. .. Here, the standby position of the second region A2 is the above-mentioned ink receiving position, that is, a position facing the capping unit 24. Further, when the first carriage 21A and the second carriage 21B are in the second region A2, the distance between the first carriage 21A and the second carriage 21B is D2.

When the formation of the image is started, the movement of the first carriage 21A is first started at the timing ta1. After the start of movement, the first carriage 21A accelerates at a predetermined acceleration and reaches a predetermined speed before reaching the position pp1. After that, the first carriage 21A ejects ink from the ink ejection head 213 while moving at a constant speed in the image forming region Rp to perform outbound printing.

Next, at the timing tb1, the movement of the second carriage 21B is started. That is, the movement of the second carriage 21B is started at the timing when the time (tb1-ta1) elapses after the movement of the first carriage 21A is started. After the start of movement, the second carriage 21B accelerates at a predetermined acceleration and reaches a predetermined speed before reaching the position pp1. After that, the second carriage 21B ejects ink from the ink ejection head 213 while moving at a constant speed in the image forming region Rp to perform outbound printing.
The speed of the first carriage 21A and the speed of the second carriage 21B at the time of outbound printing are equal to each other.

Further, at the timing tx1 when the second carriage 21B reaches the position pr1, the preceding first carriage 21A reaches the position pr2. In other words, the time (tb1-ta1) related to the movement start timing of the second carriage 21B is determined so that the first carriage 21A reaches the position pr2 when the second carriage 21B reaches the position pr1. It has been done.
At the timing tx1, the first carriage 21A and the second carriage 21B are in the first region A1 (both ends). The distance between the first carriage 21A and the second carriage 21B at this timing tx1 is D1, which is larger than the distance D2. By shifting the movement start timings of the two carriages 21 in this way, the distance D1 between the carriages 21 in the first region A1 is larger than the distance D2 between the carriages 21 in the second region A2.
After the speeds of the first carriage 21A and the second carriage 21B become constant, the distance between the first carriage 21A and the second carriage 21B is constant at D1. Therefore, both the first carriage 21A and the second carriage 21B move at a constant speed than the distance D2 between the first carriage 21A and the second carriage 21B when waiting in the second region A2. In other words, the distance D1 between the first carriage 21A and the second carriage 21B is larger.

Further, before the timing tx1, only the first carriage 21A is located in the restricted region R1 (the region of the first region A1 excluding both ends), and after the timing tx1, the restricted region R1 has a th. Only the carriage 21B of 2 will be located. Therefore, at an arbitrary timing in the outbound printing, only one carriage 21, which is the upper limit number, is located in the restricted area R1.

The first carriage 21A and the second carriage 21B stop at the standby position in the second area A3 when the outbound printing is completed. Here, the standby position in the second region A3 is the above-mentioned cleaning position, that is, a position facing the cleaning unit 23. Further, when the first carriage 21A and the second carriage 21B are in the second region A3, the distance between the first carriage 21A and the second carriage 21B is D2.

When each carriage 21 is stopped, a sub-scanning operation is performed by the transport unit 10. In the sub-scanning operation, the recording medium P is conveyed in the sub-scanning direction by a predetermined distance. In the case of the one-pass method in which the formation of the image is completed by ejecting ink in one main scanning operation for each position on the recording medium P, the above-mentioned predetermined distance is the width W shown in FIG. Further, in the case of the two-pass system in which the formation of an image is completed by ejecting ink in two main scanning operations with respect to each position on the recording medium P, the above-mentioned predetermined distance is set to W / 2.

When the sub-scanning operation is completed, the return path movement of the second carriage 21B is started at the timing tb2. After the start of movement, the second carriage 21B accelerates at a predetermined acceleration and reaches a predetermined speed before reaching the position pp2. After that, the second carriage 21B ejects ink from the ink ejection head 213 while moving at a constant speed in the image forming region Rp to perform return printing.

Next, at the timing ta2, the movement of the first carriage 21A is started. That is, the movement of the first carriage 21A is started at the timing when the time (ta2-tb2) elapses after the movement of the second carriage 21B is started. After the start of movement, the first carriage 21A accelerates at a predetermined acceleration and reaches a predetermined speed before reaching the position pp2. After that, the first carriage 21A ejects ink from the ink ejection head 213 while moving at a constant speed in the image forming region Rp to perform return printing.
The speed of the first carriage 21A and the speed of the second carriage 21B at the time of return printing are also equal to each other.

Further, at the timing tx2 when the first carriage 21A reaches the position pr2, the preceding second carriage 21B reaches the position pr1. In other words, the time (ta2-tb2) related to the movement start timing of the first carriage 21A is determined so that the second carriage 21B reaches the position pr1 when the first carriage 21A reaches the position pr2. Has been done.
At the timing tx2, the first carriage 21A and the second carriage 21B are in the first region A1 (both ends). The distance between the first carriage 21A and the second carriage 21B at this timing tx2 is D1, which is larger than the distance D2 as in the case of outbound printing.
In the above, both the first carriage 21A and the second carriage 21B are on the return path rather than the distance D2 between the first carriage 21A and the second carriage 21B when waiting in the second region A3. In other words, the distance D1 between the first carriage 21A and the second carriage 21B when moving at a constant speed is larger.

Further, before the timing tx2, only the second carriage 21B is located in the restricted area R1, and after the timing tx2, only the first carriage 21A is located in the restricted area R1. Therefore, at an arbitrary timing in the return printing, only one carriage 21, which is the upper limit number, is located in the restricted area R1.

The second carriage 21B and the first carriage 21A stop at the standby position in the second area A2 when the return printing is completed.
When each carriage 21 is stopped, a sub-scanning operation is performed by the transport unit 10.
After that, the same operation is repeatedly executed until the formation of the image on the recording medium P is completed.
The time (tb1-ta1) and time (ta2-tb2) in the above may be predetermined and stored as setting data in the storage unit 34 or the like, or are calculated each time based on the acceleration and speed of each carriage 21. You may.

Further, in the period from the start of the movement of the first carriage 21A at the timing ta1 of FIG. 7 to the start of the movement of the second carriage 21B at the timing tb1, the standby position (ink receiving position) of the second region A2. ) May be used to perform a discharge operation on the capping unit 24. That is, when one of the carriages 21 is located in the first region A1, the linear motor 215 is controlled so that the other carriage 21 is located at the ink receiving position, so that the carriage 21 stands by. It is possible to use time to perform a dumping operation. The first carriage 21A may also be discharged during the period when it is located at the standby position in the second region A2.

Further, in the period from the start of the movement of the second carriage 21B at the timing tb2 of FIG. 7 to the start of the movement of the first carriage 21A at the timing ta2, the standby position (cleaning position) of the second region A3. The first carriage 21A in the above may be cleaned by the cleaning unit 23. That is, when one of the carriages 21 is located in the first region A1, the linear motor 215 is controlled so that the other carriage 21 is located in the cleaning position, so that the standby time of the carriage 21 is reached. Can be used to perform a cleaning operation. The second carriage 21B may also be cleaned by the cleaning unit 23 during the period when it is located at the standby position in the second region A3.

Next, a control procedure of the image forming process for causing each part of the inkjet recording apparatus 1 to perform the above-mentioned image forming operation will be described.
FIG. 8 is a flowchart showing a control procedure by the control unit 30 of the image forming process.
The image forming process is started when the print job and the image data are input to the control unit 30 via the communication unit 42.

When the image formation process is started, the control unit 30 sends a control signal to the transfer motor 14 to operate the transfer unit 10 to convey the recording medium P to the image formation start position (step S101).

The control unit 30 starts the movement of the leading carriage 21 and the main scanning operation (step S102). That is, the control unit 30 sends a control signal to the linear motor 215 of the leading carriage 21 to start the movement of the carriage 21. Further, the control signal and the image data are sent to the head drive substrate 214 at an appropriate timing according to the movement time of the carriage 21, and the ink is ejected by the ink ejection head 213.

The control unit 30 determines whether or not there is a trailing carriage 21 that has not been moved (step S103), and if it is determined that there is a trailing carriage 21 (“YES” in step S103), in step S102. It is determined whether a predetermined time (for example, the above-mentioned time (tb1-ta1) or time (ta2-tb2)) has elapsed from the start of movement of the carriage 21 (step S104). If it is determined that the predetermined time has not elapsed from the start of movement of the carriage 21 (“NO” in step S104), the control unit 30 executes the process of step S104 again. When it is determined that a predetermined time has elapsed from the start of movement of the carriage 21 (“YES” in step S104), the control unit 30 shifts the process to step S102 to move the next carriage 21 and perform the main scan. Start the operation.

If it is determined in the process of step S103 that there is no unmoved subsequent carriage 21 (“NO” in step S103), the control unit 30 completes the movement of each carriage 21 and determines that there is no unrestricted area R2 or R3. It is determined whether or not the vehicle has stopped at the standby position of (step S105). If it is determined that the movement of any of the carriages 21 has not been completed (“NO” in step S105), the control unit 30 executes the process of step S105 again.

When it is determined that the movement of all the carriages 21 is completed (“YES” in step S105), the control unit 30 determines whether or not the formation of the image on the recording medium P is completed (step S106). .. When it is determined that the image formation is not completed (“NO” in step S106), the control unit 30 causes the transport unit 10 to execute the sub-scanning operation (step S107). That is, the control unit 30 sends a control signal to the transfer motor 14 to operate the transfer unit 10 and convey the recording medium P by a predetermined distance. When the sub-scanning operation is completed, the control unit 30 switches between the outward path and the return path (step S108), and shifts the process to step S102.

When it is determined in the process of step S106 that the image formation is completed (“YES” in step S106), the control unit 30 ends the image formation process.
Steps S102 to S104 in the image forming process correspond to drive control steps.

Next, the effect of shortening the image formation time by the above-described method of driving the carriage 21 will be described in comparison with a comparative example.
FIG. 9 is a diagram showing the arrangement of the ink ejection head 213 in the carriage 21 according to the comparative example.
Further, FIG. 10 is a diagram illustrating an image forming process in the comparative example and the embodiment of the configuration of the present embodiment.

As shown in FIG. 9, in the carriage 21 of the comparative example, one ink ejection head 213Y, 213M, 213C, 213K, 213LM, 213LC, 213O, and 213G are mounted, and these eight ink ejection heads 213 are mounted. Are arranged in a houndstooth pattern.
The inkjet recording device of the comparative example uses only this one carriage 21 to form an image. Specifically, for each position on the recording medium P, first, ink of the basic color is ejected from the ink ejection heads 213Y, 213M, 213C, and 213K on the downstream side in the transport direction, and then the recording medium P is ejected by the width W / 2. A sub-scanning operation for conveying is executed, and auxiliary color ink is ejected from the ink ejection heads 213LM, 213LC, 213O, and 213G on the upstream side in the conveying direction.

Therefore, as shown in the upper part of FIG. 10, in the inkjet recording device of the comparative example, the image portion is completed by the width W / 2 in the sub-scanning direction by the one-way main scanning operation of the outward path or the return path. Therefore, for example, in order to form an image having a width of 2 W, two reciprocating main scanning operations are required, and three sub-scanning operations are executed during that period.

On the other hand, according to the embodiment of the present embodiment, as shown in FIG. 3, two ink ejection heads 213 of each color are provided, so that ink of each color can be ejected over the width W. .. Therefore, as shown in the lower part of FIG. 10, the image portion can be completed by the width W in the sub-scanning direction by the one-way main scanning operation by the two carriages 21. Therefore, in order to form an image having a width of 2 W, only one reciprocating main scanning operation is sufficient, and only one sub-scanning operation is required during that period.
Further, in the embodiment, in addition to requiring less sub-scanning operation as compared with the comparative example, in the one-way main scanning operation, as described above, the first carriage 21A and the second carriage 21B are used simultaneously in parallel. There is a parallel ejection period T for ejecting ink. The image formation time can be further shortened as compared with the comparative example by the amount of the parallel discharge period T.

Next, a modified example of the above embodiment will be described. The following modifications can be appropriately combined as long as the gist of the present invention is not deviated.

(Modification example 1)
Modification 1 is different from the above embodiment in that an image is formed by using three carriages 21, and is the same as the above embodiment in other points. The differences from the above-described embodiment will be described below.

In this modification, the first carriage 21A, the second carriage 21B, and the third carriage 21C are attached to the support member 221. The ink ejection head 213 mounted on each carriage 21 is not particularly limited, but for example, the third carriage 21C has a different color from the ink ejection heads 213 of the first carriage 21A and the second carriage 21B. Eight ink ejection heads 213 that eject ink can be mounted.

Further, in this modification, the carriage 21 is driven so that the number of carriages 21 located in the limited area R1 is within two at an arbitrary timing. Therefore, the upper limit of the number of carriages 21 in this modification is "2".

FIG. 11 is a diagram illustrating a method of driving the carriage 21 according to the first modification.
As shown in FIG. 11, the distance between adjacent carriages 21 when the three carriages 21 are in the second area A2, that is, the distance between the first carriage 21A and the second carriage 21B, and the second carriage. The distance between the 21B and the third carriage 21C is D2.

First, the movement of the first carriage 21A is started at the timing ta1.
Next, at the timing tb1, that is, at the timing when the time (tb1-ta1) has elapsed after the start of the movement of the first carriage 21A, the movement of the second carriage 21B is started.
Next, at the timing tc1, that is, at the timing when the time (tk1-tb1) has elapsed after the start of the movement of the second carriage 21B, the movement of the third carriage 21C is started.
The speeds of the carriages 21 during outbound printing are equal to each other.

Further, at the timing tx1 when the second carriage 21B reaches the position pr1, the preceding first carriage 21A reaches the position pr3 (the midpoint between the position pr1 and the position pr2). In other words, the time (tb1-ta1) related to the movement start timing of the second carriage 21B is determined so that the first carriage 21A reaches the position pr3 when the second carriage 21B reaches the position pr1. It has been done.

Further, at the timing tx2 when the third carriage 21C reaches the position pr1, the preceding second carriage 21B reaches the position pr3. In other words, the time (tc1-tb1) related to the movement start timing of the third carriage 21C is determined so that the second carriage 21B reaches the position pr3 when the third carriage 21C reaches the position pr1. It has been done.

Further, at the timing tx2, the first carriage 21A reaches the position pr2 and moves to the outside of the first region A1 after the timing tx2.
Further, at the timing tx3, the second carriage 21B reaches the position pr2 and moves to the outside of the first region A1 after the timing tx3.

From the timing tx1 to tx2, the first carriage 21A and the second carriage 21B are located in the first region A1, and the interval between them is D1 (> D2). Further, between the timings tx2 and tx3, the second carriage 21B and the third carriage 21C are located in the first region A1, and the interval between them is D1 (> D2). As described above, also in this modification, by shifting the movement start timing of each carriage 21, the distance D1 between any adjacent pair of carriages 21 in the first region A1 becomes the pair in the second region A2. The distance between the carriages 21 is larger than D2.

Further, before the timing tx2, only the first carriage 21A or only the first carriage 21A and the second carriage 21B are located in the restricted area R1, and after the timing tx2, only the first carriage 21A and the second carriage 21B are located in the restricted area R1. , Only the third carriage 21C, or only the second carriage 21B and the third carriage 21C will be located. Therefore, at an arbitrary timing in the outbound printing, two or less carriages 21, which are the upper limit, are located in the restricted area R1.

When the outbound printing is completed, each carriage 21 stops at the standby position in the second area A3. The distance between adjacent carriages 21 when the three carriages 21 are in the second region A3, that is, the distance between the first carriage 21A and the second carriage 21B, and the distance between the second carriage 21B and the third carriage 21C. The interval between and is D2.
When each carriage 21 is stopped, a sub-scanning operation is performed by the transport unit 10.

When the sub-scanning operation is completed, the return path movement of the third carriage 21C is started at the timing tc2.
Next, at the timing tb2, that is, at the timing when the time (tb2-tc2) has elapsed after the start of the movement of the third carriage 21C, the movement of the second carriage 21B is started.
Next, at the timing ta2, that is, at the timing when the time (ta2-tb2) has elapsed after the start of the movement of the second carriage 21B, the movement of the first carriage 21A is started.
The speed of each carriage 21 at the time of return printing is also equal to each other.

Further, at the timing tx4 when the second carriage 21B reaches the position pr2, the preceding third carriage 21C reaches the position pr3. In other words, the time (tb2-tk2) related to the movement start timing of the second carriage 21B is determined so that the third carriage 21C reaches the position pr3 when the second carriage 21B reaches the position pr2. Has been done.

Further, at the timing tx5 when the first carriage 21A reaches the position pr2, the preceding second carriage 21B reaches the position pr3. In other words, the time (ta2-tb2) related to the movement start timing of the first carriage 21A is determined so that the second carriage 21B reaches the position pr3 when the first carriage 21A reaches the position pr2. Has been done.

Further, at the timing tx5, the third carriage 21C reaches the position pr1 and moves to the outside of the restricted region R1 after the timing tx5.
Further, at the timing tx6, the second carriage 21B reaches the position pr1 and moves to the outside of the restriction region R1 after the timing tx6.

From the timing tx4 to tx5, the third carriage 21C and the second carriage 21B are located in the first region A1, and the interval between them is D1 (> D2). Further, between the timings tx5 and tx6, the second carriage 21B and the first carriage 21A are located in the first region A1, and the interval between them is D1 (> D2). In this way, even on the return path, by shifting the movement start timing of each carriage 21, the distance between any adjacent pair of carriages 21 in the first region A1 can be changed to the pair of carriages 21 in the second region A3. It is larger than the distance between each other.

Further, before the timing tx5, only the third carriage 21C or only the second carriage 21B and the third carriage 21C are located in the restricted area R1, and after the timing tx5, only the third carriage 21C is located in the restricted area R1. Only the first carriage 21A, or only the first carriage 21A and the second carriage 21B will be located. Therefore, at an arbitrary timing in the return printing, two or less carriages 21, which are the upper limit, are located in the restricted area R1.

When the return printing is completed, each carriage 21 stops at the standby position in the second area A2. When all the carriages 21 are stopped, the sub-scanning operation is performed by the transport unit 10.
After that, the same operation is repeatedly executed until the formation of the image on the recording medium P is completed.

Although the above is an example when the upper limit number is "2", the upper limit number may be set to "1" even when the number of carriages 21 is three.
Further, the number of carriages may be four or more. Also in this case, the movement start timing of each carriage 21 is controlled so that the number of carriages 21 located in the restriction region R1 is equal to or less than the upper limit number at an arbitrary timing. When the number of carriages is four, the upper limit is set to any one of "1" to "3".

(Modification 2)
Next, a modification 2 of the above embodiment will be described. In this modification, the method of determining the movement start timing of each carriage 21 is different from that of the above embodiment, and other points are the same as those of the above embodiment. The differences from the above-described embodiment will be described below.

In this modification, the control unit 30 starts the movement of one of the plurality of carriages 21 and then relates to the position of the carriage 21 based on the signal received from the linear encoder 216 of the carriage 21. Get location information. Then, the control unit 30 determines the movement start timing of the next carriage 21 based on this position information.

Specifically, in the example using the two carriages 21 shown in FIG. 7, the second carriage at the timing tb1 when the first carriage 21A reaches the position pa after the movement of the first carriage 21A is started at the timing ta1. The movement of 21B is started. As for the position pa, the first carriage 21A is set to the position pr2 when the time required from the start of the movement of the second carriage 21B at the timing tb1 to the arrival at the position pr1 is tm1 (= tx1-tb1). This is the position of the first carriage 21A at a timing tm1 before the arrival timing.

The same applies to the return path, and after the movement of the second carriage 21B is started at the timing tb2, the movement of the first carriage 21A is started at the timing ta2 when the second carriage 21B reaches the position pb. As for the position pb, when the time required from the start of the movement of the first carriage 21A at the timing ta2 to the arrival at the position pr2 is tm2 (= tx2-ta2), the second carriage 21B is set to the position pr1. This is the position of the second carriage 21B at a timing tm2 before the arrival timing.
The control method of this modification also allows the carriages 21 to be driven so that the positions of the carriages 21 at each time point are the same as those in FIG.

Further, in the example using the three carriages 21 shown in FIG. 11, after the movement of the first carriage 21A is started at the timing ta1, the second carriage 21B is reached at the timing tb1 when the first carriage 21A reaches the position pa1. Start moving. At the position pa1, the first carriage 21A is set to the position pr3 when the time required from the start of the movement of the second carriage 21B at the timing tb1 to the arrival at the position pr1 is tn1 (= tx1-tb1). This is the position of the first carriage 21A at a timing that is time tn1 before the arrival timing.
Further, after the movement of the second carriage 21B is started at the timing tb1, the movement of the third carriage 21C is started at the timing tc1 when the second carriage 21B reaches the position pb1. At the position pb1, the second carriage 21B moves to the position pr3 when the time required from the start of the movement of the third carriage 21C at the timing tc1 to the arrival at the position pr1 is tn2 (= tx2-tk1). This is the position of the second carriage 21B at a timing two times before the arrival timing.

The same applies to the return path, and after the movement of the third carriage 21C is started at the timing tc2, the movement of the second carriage 21B is started at the timing tb2 when the third carriage 21C reaches the position pc2. At the position pc2, when the time required from the start of the movement of the second carriage 21B at the timing tb2 to the arrival at the position pr3 is tn3 (= tx4-tb2), the third carriage 21C is moved to the position pr3. This is the position of the third carriage 21C at a timing that is time tun3 before the arrival timing.
Further, after the movement of the second carriage 21B is started at the timing tb2, the movement of the first carriage 21A is started at the timing ta2 when the second carriage 21B reaches the position pb2. At the position pb2, when the time required from the start of the movement of the first carriage 21A at the timing ta2 to the arrival at the position pr3 is tn4 (= tx5-ta2), the second carriage 21B is moved to the position pr3. This is the position of the second carriage 21B at a timing that is time tn4 before the arrival timing.
The control method of this modification also allows the carriages 21 to be driven so that the positions of the carriages 21 at each time point are the same as those in FIG.

FIG. 12 is a flowchart showing a control procedure by the control unit 30 of the image forming process according to the second modification.
The flowchart of FIG. 12 corresponds to a change of step S104 of the flowchart of FIG. 8 to step S104a. Hereinafter, the differences from the flowchart of FIG. 8 will be described.
In the image forming process of FIG. 12, in the process of step S102, the control unit 30 sends a control signal to the linear motor 215 of the leading carriage 21 to start the movement of the carriage 21 and the signal from the linear encoder 216. Reception is started to acquire the position information related to the position of the carriage 21.
If it is determined in the process of step S103 that there is a subsequent carriage 21 that has not been moved (“YES” in step S103), the control unit 30 determines that the carriage 21 that has started moving in step S102 is in a predetermined position. It is determined whether or not it has been reached (step S104a). For example, in the example of FIG. 7, the control unit 30 determines whether or not the first carriage 21A that has started moving has reached the position pa shown in FIG. If it is determined that the carriage 21 has not reached the predetermined position (“NO” in step S104a), the control unit 30 executes the process of step S104a again. When it is determined that the carriage 21 has reached a predetermined position (“YES” in step S104a), the control unit 30 shifts the process to step S102 and starts the next movement of the carriage 21 and the main scanning operation. Let me.

(Modification example 3)
Next, a modification 3 of the above embodiment will be described. In this modification, the ink ejection head 213 that ejects ink of the same color is mounted on the two carriages 21, and the non-ejection of ink by the ink ejection head 213 of one carriage 21 is prevented from the ink ejection head 213 of the other carriage 21. It differs from the above-described embodiment in that it is complemented by the above-mentioned embodiment, and is the same as the above-described embodiment in other points. The differences from the above-described embodiment will be described below.

FIG. 13 is a diagram showing the arrangement of the ink ejection head 213 in the carriage 21 according to the modified example 3.
In this modification, two ink ejection heads 213Y, 213M, 213C, and 213K of basic colors are mounted on the first carriage 21A and the second carriage 21B, respectively, and eight ink ejection heads 213 are arranged. Are the same. Further, each ink ejection head 213 is arranged so that the position of the nozzle N in the sub-scanning direction of the first carriage 21A and the position of the nozzle N in the sub-scanning direction of the second carriage 21B coincide with each other. In this way, by mounting the image forming operation unit 212 having the ink ejection head 213 that ejects ink of the same color on the first carriage 21A and the second carriage 21B, the recording medium P on the mounting surface 13a On the other hand, the ink ejected from the ink ejection head 213 of each carriage 21 can be overlapped and landed on the recording medium P. Thereby, the density of the image can be adjusted by adjusting the amount of ink ejected from the ink ejection head 213 of each carriage 21.

FIG. 14 is a diagram illustrating complementary ejection of ink in the third modification.
As shown in FIG. 14, in this modification, when the nozzle Na in the ink ejection head 213 of the first carriage 21A is a defective nozzle that cannot eject ink, the ink ejection head 213 of the second carriage 21B Complementary discharge is performed by nozzles Nb having the same position in the transport direction. That is, the control unit 30 ejects ink that has not been ejected from the ink ejection head 213 of a part of the carriage 21 to the recording medium P on the mounting surface 13a from the ink ejection head 213 of the other carriage 21. Complement with the ink. As a result, deterioration of image quality due to defective nozzles is suppressed.
The nozzle for complementary discharge is not limited to the nozzle Nb having the same position in the transport direction, and a nearby nozzle having a short distance from the nozzle Nb in the transport direction may be further used for complementary discharge.
Further, the target of complementation is not limited to defective nozzles that cannot eject ink. The ink ejection from the nozzle N, which has a defective ink ejection amount or ejection direction, may be stopped and complemented by the ink ejection head 213 of the other carriage 21.

(Modification example 4)
Next, a modification 4 of the above embodiment will be described. In this modification, the ink ejection head 213 that ejects ink of the same color is mounted on the two carriages 21, and the positional relationship of the ink ejection head 213 in each carriage 21 is different from the above embodiment, and other points. Is the same as the above embodiment. The differences from the above-described embodiment will be described below.

FIG. 15 is a diagram showing the arrangement of the ink ejection head 213 in the carriage 21 according to the modified example 4.
In the present modification 4, similarly to the modification 3, two ink ejection heads 213Y, 213M, 213C, and 213K of the basic colors are mounted on the first carriage 21A and the second carriage 21B, respectively. The arrangement of the two ink ejection heads 213 is the same.
However, as shown in FIG. 15, in this modification, the position of the nozzle N of the first carriage 21A in the sub-scanning direction (arrangement direction of the nozzles N) is the sub-scanning direction of the nozzle N of the second carriage 21B. It is different from the position about. That is, the ink ejection heads 213 of each carriage 21 are arranged so that the positions of the nozzles N in the sub-scanning direction are different from each other. As a result, the recording resolution of the image in the sub-scanning direction can be doubled.

It should be noted that three or more carriages 21 may be provided so that the positions of the nozzles N of each carriage 21 may be different. As a result, the recording resolution in the sub-scanning direction can be further increased.
Further, in the example of FIG. 15, the position of the nozzle N is changed by adjusting the mounting position of the ink ejection head 213 in each carriage 21, but by adjusting the relative position of the carriage 21 with respect to the sub-scanning direction. The position of the nozzle N may be different.

(Modification 5)
Next, a modification 5 of the above embodiment will be described. This modification is different from the above embodiment in that the image forming operation unit 212 mounted on the carriage 21 has an ultraviolet irradiation unit 217 and a functional liquid application unit 218, and is the same as the above embodiment in other points. Is. The differences from the above-described embodiment will be described below.

FIG. 16 is a diagram showing the configuration of the carriage 21 according to the modified example 5.
In this modification, the image forming operation unit 212 of the first carriage 21A imparts a predetermined functional liquid to the ultraviolet irradiation unit 217 that irradiates the ink ejected on the recording medium P with ultraviolet rays and the recording medium P. It has a functional liquid applying unit 218 and a function liquid applying unit 218. The ultraviolet irradiation unit 217 is arranged on the downstream side in the main scanning direction (the head side in the outward path) of the eight ink ejection heads 213, and the functional liquid application unit 218 is arranged on the downstream side in the main scanning direction of the ultraviolet irradiation unit 217. ing.
Further, the image forming operation unit 212 of the second carriage 21B also has an ultraviolet irradiation unit 217 and a functional liquid application unit 218. In the second carriage 21B, the ultraviolet irradiation unit 217 is arranged on the upstream side (the head side in the return path) of the eight ink ejection heads 213 in the main scanning direction, and the functional liquid application unit 218 is the main of the ultraviolet irradiation unit 217. It is located upstream in the scanning direction.
The positional relationship between the ultraviolet irradiation unit 217 and the functional liquid application unit 218 may be reversed.

The ink ejection head 213 of this modified example ejects ultraviolet curable ink whose viscosity increases and is cured by irradiating with ultraviolet rays. The ultraviolet irradiation unit 217 irradiates the ink ejected from the ink ejection head 213 onto the recording medium P with ultraviolet rays to cure the ink. The ultraviolet irradiation operation by the ultraviolet irradiation unit 217 is one aspect of the operation related to the formation of an image on the recording medium P on the mounting surface 13a.
In the outbound printing, the second carriage 21A and the second carriage 21B are located on the rear end side in the traveling direction of the carriage 21 with respect to the ink ejected on the recording medium P by the ink ejection head 213 of the second carriage 21B. Ultraviolet rays are irradiated by the ultraviolet irradiation unit 217 of the carriage 21B.
Further, in the return printing, the ink ejected on the recording medium P by the ink ejection head 213 of the second carriage 21B and the first carriage 21A is located at the rear end side in the traveling direction of the carriage 21. Ultraviolet rays are irradiated by the ultraviolet irradiation unit 217 of the carriage 21A of 1.

The functional liquid application unit 218 applies the functional liquid for improving the image quality of the recorded image to the recording medium P before ejecting the ink. Examples of the functional liquid include a pretreatment agent for facilitating the penetration of ink into the recording medium P, a pretreatment agent for making it difficult for the ink to penetrate into the recording medium P such as cloth, and suppressing bleeding. Examples thereof include a flocculant that agglomerates a disperse material such as pigment particles in the ink by contacting with the ink to increase the viscosity of the ink. The operation of applying the functional liquid by the functional liquid applying unit 218 is one aspect of the operation related to the formation of an image on the recording medium P on the mounting surface 13a.
In the outbound printing, the functional liquid is applied to the recording medium P by the functional liquid application unit 218 of the first carriage 21A, which is located on the leading side in the traveling direction of the carriage 21, and then the first carriage 21A and the second carriage 21A and the second carriage 21A are supplied with the functional liquid. Ink is ejected by the ink ejection head 213 of the carriage 21B.
Further, in the return printing, the functional liquid is applied to the recording medium P by the functional liquid application unit 218 of the second carriage 21B located on the leading side in the traveling direction of the carriage 21, and then the second carriage 21B and the second carriage 21B and the second carriage 21B are applied. Ink is ejected by the ink ejection head 213 of the carriage 21A of 1.

In this modification, the image forming operation unit 212 mounted on each carriage 21 has an ink ejection head 213, an ultraviolet irradiation unit 217, and a functional liquid application unit 218. Not limited to this.
For example, a part of the carriage 21 may be equipped with an image forming operation unit 212 having only an ultraviolet irradiation unit 217. In this case, by providing the carriage 21 equipped with the ultraviolet irradiation unit 217 on both sides of the carriage 21 equipped with the ink ejection head 213, the ink after ejection is irradiated with ultraviolet rays in both the outward route and the return route. Ultraviolet rays can be irradiated by the part 217.
Further, the image forming operation unit 212 having only the functional liquid application unit 218 may be mounted on some of the carriages 21. In this case, by providing the carriage 21 on which the functional liquid application unit 218 is mounted on both sides of the carriage 21 on which the ink ejection head 213 is mounted, the recording medium P before ink ejection is provided on both the outward path and the return path. The functional liquid can be applied by the functional liquid application unit 218.
Further, the inkjet recording device 1 may have a configuration that does not have one of the ultraviolet irradiation unit 217 and the functional liquid application unit 218.

As described above, the inkjet recording device 1 as the image forming apparatus according to the present embodiment relates to the carriage belt 13 having the mounting surface 13a on which the recording medium P is mounted and the recording medium P on the mounting surface 13a. A plurality of carriages 21 on which an image forming operation unit 212 that performs an operation related to image formation is mounted, and a plurality of carriages 21 can be reciprocated along a predetermined movement path Rmv passing over the mounting surface 13a. A moving path including a supporting member 221 to support, a linear motor 215 for independently moving each of the plurality of carriages 21 along the moving path Rmv, and a control unit 30 as a drive control means for controlling the linear motor 215. The Rmv includes a first region A1 and second regions A2 and A3 on the end side of the movement path Rmv with respect to the first region A1, and the control unit 30 moves among the plurality of carriages 21. When there are at least two or more carriages 21, the distance D1 between the pair of carriages 21 when any adjacent pair of carriages 21 among the plurality of carriages 21 is in the first region A1 is a pair. The linear motor 215 is controlled so as to be larger than the distance D2 between the pair of carriages 21 when the carriages 21 are in the second regions A2 and A3 (drive control means).
According to this, it is possible to prevent the timing at which a large number of carriages 21 are concentrated in the first region A1 on the central side of the movement path Rmv. Therefore, the weight of the support member 221 on the limiting region R1 can be suppressed to a predetermined value or less at an arbitrary timing. Therefore, the bending of the support member 221 can be suppressed within a desired range. As a result, it is possible to suppress the occurrence of problems such as the distance between the carriage 21 and the recording medium P becoming short due to the bending of the support member 221 and the ink landing position being displaced, or the carriage 21 coming into contact with the recording medium P. be able to. As a result, an image can be appropriately formed even if two or more carriages of the plurality of carriages 21 are moved at the same time, so that the image can be formed in a short time and the throughput of image formation can be increased. Further, since the strength required for the support member 221 can be suppressed, the cost of the support member 221 can be reduced, or the support member 221 can be made longer while suppressing the cost increase. By lengthening the support member 221, an image can be formed in a short time even on a recording medium P having a larger size in the main scanning direction. Further, since bending during driving can be suppressed even if a plurality of carriages 21 are attached to one support member 221, the support member 221, the linear guide 222, the linear motor magnet 223, the linear scale 224, and the like can be attached to the plurality of carriages 21. Can be shared by. Therefore, the manufacturing cost of the device can be effectively suppressed.

Further, a second region A2 is set on both sides of the first region A1. According to this, in each of the outward path and the return path of the movement path Rmv, the carriages are made to stand by in the second region A2 (A3) with a small distance between the carriages 21 before the start of the movement, and in the first region A1 after the start of the movement. The carriage 21 can be moved so that the distance between the carriages 21 is widened, and after the movement is completed, a series of operations can be performed in the second region A3 (A2) on the opposite side so that the distance between the carriages 21 is small. .. Therefore, the main scanning operation of the outward path and the return path can be repeated while suppressing the bending of the support member 221.

Further, the control unit 30 determines that the number of carriages 21 in the restricted area R1 inside the first region A1 among the plurality of carriages 21 is less than the number of carriages 21 included in the plurality of carriages 21. The linear motor 215 is controlled so as to be equal to or less than the upper limit (drive control means). According to this, the weight of the support member 221 applied to the limiting region R1 can be more reliably suppressed to a predetermined value or less at an arbitrary timing. Therefore, the bending of the support member 221 can be suppressed within a desired range.

Further, the control unit 30 determines the movement start timing of the next carriage 21 based on the elapsed time after starting the movement of one of the plurality of carriages 21. According to this, it is possible to form an image with high throughput while suppressing the bending of the support member 221 with simple control.

Further, the control unit 30 according to the second modification acquires the position information related to the position in each movement path Rmv of the plurality of carriages 21 (position information acquisition means), and moves one of the plurality of carriages 21. Is started, and then the movement start timing of the next carriage 21 is determined based on the position information related to the position of the one carriage 21 (drive control means). According to this, it is possible to form an image with high throughput while suppressing the bending of the support member 221 with simple control.

Further, the image forming operation unit 212 operates when the carriage 21 on which the image forming operation unit 212 is mounted is within a predetermined image forming region Rp in the movement path Rmv, and the first region A1 forms an image. Includes at least a portion of the region Rp. According to this, it is possible to suppress the occurrence of a problem that the support member 221 is bent in the image forming region Rp and the image quality is deteriorated.

Further, the first region A1 is set inside from both ends of the image forming region Rp. According to this, at least two carriages 21 can be simultaneously positioned in the image forming region Rp. By ejecting ink from the ink ejection heads 213 of each carriage 21 in parallel at this timing, an image can be formed in a shorter time.

Further, the control unit 30 controls the linear motor 215 so that two or more carriages 21 out of the plurality of carriages 21 are simultaneously located in the image forming region Rp at any timing (drive control means). According to this, ink can be ejected simultaneously and in parallel from the ink ejection heads 213 of two or more carriages 21 to the same recording medium P. Therefore, the image can be formed in a shorter time.

Further, at least a part of the plurality of carriages 21 is equipped with an image forming operation unit 212 having an ink ejection head 213 for ejecting ink to the recording medium P, and the control unit 30 moves the carriage 21. Ink is ejected by the ink ejection head 213 at a corresponding timing (ejection control means). According to this, it is possible to appropriately form an image while suppressing deterioration of image quality due to bending of the support member 221.

A cleaning unit 23 for cleaning the ink ejection head 213 of the carriage 21 located at a predetermined cleaning position on the outside of the image forming region Rp is provided, and the control unit 30 has at least one of the plurality of carriages 21 in the first region A1. The linear motor 215 is controlled so that at least one of the plurality of carriages 21 on which the ink ejection head 213 is mounted is located at the cleaning position (drive control means). According to this, the ink ejection head 213 can be cleaned during the execution of the image forming operation. Therefore, the throughput of image formation can be further increased as compared with the conventional technique of cleaning the ink ejection head 213 during the period when the image formation operation is not performed. Further, since the cleaning unit 23 can be shared by a plurality of carriages 21, the cost can be further reduced.

Further, the control unit 30 includes a capping unit 24 that receives ink ejected from the ink ejection head 213 of the carriage 21 located at a predetermined ink receiving position outside the image forming region Rp, and the control unit 30 is at least one of the plurality of carriages 21. The linear motor 215 is controlled so that at least one of the plurality of carriages 21 on which the ink ejection head 213 is mounted is located at the ink receiving position when one is located in the first region A1 (drive control means). ). According to this, the ink ejection head 213 can perform the ejection disposal operation during the execution of the image forming operation. Therefore, the throughput of image formation can be further increased as compared with the conventional technique of causing the ink ejection head 213 to perform the ejection operation during the period when the image forming operation is not performed. Further, since the capping unit 24 can be shared by a plurality of carriages 21, the cost can be further suppressed.

Further, at least one of the plurality of carriages 21 is equipped with an image forming operation unit 212 having a plurality of first ink ejection heads 213 for ejecting inks of a plurality of basic colors, and the plurality of carriages 21. At least one of them is equipped with an image forming operation unit 212 having a second ink ejection head 213 for ejecting inks of a plurality of auxiliary colors other than the basic colors, and the control unit 30 is a first. The first mode in which the ink is ejected by the ink ejection head 213 and the second ink ejection head 213, and the second mode in which the ink is ejected by the first ink ejection head 213 and the ink is not ejected by the second ink ejection head 213. Ink is ejected by the ink ejection head 213 in one of the modes selected from the two modes (ejection control means). According to this, it is possible to easily switch between image formation using a combination of basic colors and auxiliary colors and image formation using only basic colors. Further, it is possible to effectively suppress the occurrence of bending of the support member 221 in the first mode in which the basic color and the auxiliary color are combined.

Further, in the third modification, at least two carriages 21 of the plurality of carriages 21 are equipped with an image forming operation unit 212 having an ink ejection head 213 for ejecting ink of the same color, and a control unit. Reference numeral 30 denotes an ink ejected from each of the ink ejection heads 213 of at least two carriages 21 being superposed on the recording medium P and landed on the recording medium P on the mounting surface 13a (ejection control means). According to this, the density of the formed image can be adjusted by adjusting the amount of ink ejected from the ink ejection head 213 of each carriage 21.

Further, the control unit 30 of the modification 3 transfers ink that has not been ejected from the ink ejection head 213 of a part of the carriages 21 out of at least two carriages 21 to the recording medium P on the mounting surface 13a. The ink ejected from the ink ejection head 213 of any of the other carriages 21 of the at least two carriages 21 complements the ink (ejection control means). According to this, even if a nozzle N with poor ink ejection occurs in the ink ejection head 213 of any of the carriages 21, deterioration of image quality can be suppressed.

Further, in the modified example 4, at least two carriages 21 of the plurality of carriages 21 are equipped with an image forming operation unit 212 having an ink ejection head 213 for ejecting ink of the same color, and each ink is mounted. The ejection head 213 is provided with a plurality of nozzles N for ejecting ink at predetermined intervals in an arrangement direction orthogonal to the moving direction of the carriage 21 along the moving path Rmv, and each of the at least two carriages 21. The ink ejection heads 213 are arranged so that the positions of the nozzles N in the arrangement direction are different from each other. According to this, it is possible to increase the recording resolution of the image in the sub-scanning direction with a simple configuration.

Further, in the modification 5, the ink ejection head 213 ejects ink that is cured by irradiating with ultraviolet rays, and at least a part of the plurality of carriages 21 irradiates the ink ejected on the recording medium P with ultraviolet rays. An image forming operation unit 212 having an ultraviolet irradiation unit 217 is mounted. According to this, the ink can be cured in the main scanning operation of the carriage 21. Therefore, it is not necessary to separately provide a device for irradiating the ultraviolet rays to the outside of the carriage 21, so that the cost can be suppressed.

Further, in the modified example 5, at least a part of the plurality of carriages 21 is equipped with an image forming operation unit 212 having a functional liquid applying unit 218 for applying a predetermined functional liquid to the recording medium P. According to this, the functional liquid can be applied to the recording medium P in the main scanning operation of the carriage 21. Therefore, it is not necessary to separately provide a device for applying the functional liquid to the outside of the carriage 21, so that the cost can be suppressed.

Further, the inkjet recording device 1 includes a transport unit 10 that transports the recording medium P in the transport direction by moving the mounting surface 13a of the transport belt 13 in a transport direction that intersects the moving direction of the carriage 21. According to this, an image can be formed in a desired range of the recording medium P by repeating the main scanning operation of the carriage 21 and the sub-scanning operation of the transport unit 10.

Further, in the method of driving the carriage 21 according to the present embodiment, when there are at least two moving carriages 21 among the plurality of carriages 21, any pair of adjacent carriages 21 among the plurality of carriages 21 can be used. The linear motor 215 is set so that the distance between the pair of carriages 21 when they are in the first area A1 is larger than the distance between the pair of carriages 21 when the pair of carriages 21 are in the second area A2. Includes drive control steps to control. According to such a method, it is possible to appropriately form an image by suppressing the occurrence of defects caused by the bending of the support member 221. In addition, it is possible to increase the throughput of image formation by forming an image in a short time while suppressing the cost.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, the number, arrangement, and number of colors of the ink ejection heads 213 mounted on the carriage 21 of the above embodiment are examples, and can be appropriately changed according to the content of the image to be formed and the like.

Further, in the above embodiment, the first region A1 and the restricted region R1 are set inside from both ends of the image forming region Rp, but the present invention is not limited to this, and the first region A1 or the restricted region R1 forms an image. It may coincide with the region Rp, or at least one of the first region A1 and the limiting region R1 may be a region wider than the image forming region Rp including the entire image forming region Rp.

Further, in the above embodiment, the restriction region R1 has been described with reference to an example in which both ends of the first region A1 are excluded, but the present invention is not limited to this, and the restriction region R1 is the first region A1. It can be any area inside both ends.

Further, in the above embodiment, the cleaning unit 23 is provided only on one side of the movement path in the main scanning direction of the carriage 21, but instead, it may be provided on both sides of the movement path. By doing so, it is possible to perform the cleaning operation on the ink ejection head 213 of the carriage 21 during each standby time after the end of the outbound printing and the end of the inbound printing.

Further, in the above embodiment, the capping unit 24 has been described by using an example in which the capping unit 24 is provided only on one side of the movement path in the main scanning direction of the carriage 21, but instead, it may be provided on both sides of the movement path. By doing so, the ink ejection head 213 of the carriage 21 can cause the ink ejection head 213 to perform the ejection discharge operation in each waiting time after the end of the outbound printing and the end of the inbound printing.

Further, the auxiliary color is not limited to LM, LC, O, and G, and ink of any auxiliary color other than the basic color such as B (blue) and R (red) can be used.

Although some embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and the equivalent scope thereof. ..

1 Inkjet recording device (image forming device)
10 Transport unit 11 Drive roller 12 Driven roller 13 Transport belt (mounting member)
13a Mounting surface 14 Conveying motor 20 Recording unit 21, 21A, 21B, 21C Carriage 211 Housing 211a Bottom surface 212 Image forming operation unit 213 Ink ejection head 214 Head drive board 215 Linear motor (drive unit)
216 Linear encoder 217 Ultraviolet irradiation unit 218 Functional liquid application unit 22 Main scanning rail 221 Support member 222 Linear guide 223 Linear motor magnet 224 Linear scale 225 Support column 23 Cleaning unit 24 Capping unit 30 Control unit (drive control means, position information acquisition means, Discharge control means)
31 CPU
32 RAM
33 ROM
34 Storage unit 41 Operation display unit 42 Communication unit 43 Bus N Nozzle P Recording medium A1 First area A2, A3 Second area R1 Restricted area R2, R3 Unrestricted area Rmv Movement path Rp Image formation area

Claims (19)

A mounting member having a mounting surface on which the recording medium is mounted, and
A plurality of carriages each equipped with an image forming operation unit that performs an operation related to image formation on a recording medium on the mounting surface described above, and
A support member that supports the plurality of carriages so as to be reciprocally movable along a predetermined movement path passing over the above-mentioned mounting surface.
A drive unit that independently moves each of the plurality of carriages along the movement path,
A drive control means for controlling the drive unit and
With
The movement path includes a first region and a second region on the end side of the movement path with respect to the first region.
The drive control means is used when there are at least two moving carriages among the plurality of carriages, and when any adjacent pair of carriages among the plurality of carriages are in the first region. An image forming apparatus, characterized in that the drive unit is controlled so that the distance between the pair of carriages is larger than the distance between the pair of carriages when the pair of carriages is in the second region. The image forming apparatus according to claim 1, wherein the second region is provided on both sides of the first region. The drive control means has a predetermined upper limit in which the number of carriages in a predetermined limiting area inside the first region of the plurality of carriages is less than the number of carriages included in the plurality of carriages. The image forming apparatus according to claim 1 or 2, wherein the drive unit is controlled so as to be a number or less. One of claims 1 to 3, wherein the drive control means determines the movement start timing of the next carriage based on the elapsed time after starting the movement of one of the plurality of carriages. The image forming apparatus according to one item. A position information acquisition means for acquiring position information relating to a position in the movement path of each of the plurality of carriages is provided.
The drive control means is characterized in that after starting the movement of one of the plurality of carriages, the movement start timing of the next carriage is determined based on the position information related to the position of the one carriage. The image forming apparatus according to any one of claims 1 to 3. The image forming operation unit performs the operation when the carriage on which the image forming operation unit is mounted is within a predetermined image forming region in the movement path.
The image forming apparatus according to any one of claims 1 to 5, wherein the first region includes at least a part of the image forming region. The image forming apparatus according to claim 6, wherein the first region is set inside both ends of the image forming region. 6. Or 7, the drive control means controls the drive unit so that two or more carriages among the plurality of carriages are simultaneously located in the image forming region at any timing. The image forming apparatus according to. At least a part of the plurality of carriages is equipped with the image forming operation unit having an ink ejection head for ejecting ink to the recording medium.
The image forming apparatus according to any one of claims 6 to 8, wherein the image forming apparatus includes an ejection control means for ejecting ink by the ink ejection head at a timing corresponding to the movement of the carriage. .. A cleaning unit for cleaning the ink ejection head of the carriage at a predetermined cleaning position on the outside of the image forming region is provided.
In the drive control means, when at least one of the plurality of carriages is located in the first region, at least one of the plurality of carriages on which the ink ejection head is mounted is in the cleaning position. The image forming apparatus according to claim 9, wherein the drive unit is controlled so as to be located. An ink receiving unit that receives ink ejected from the ink ejection head of the carriage at a predetermined ink receiving position on the outside of the image forming region is provided.
In the drive control means, when at least one of the plurality of carriages is located in the first region, at least one of the plurality of carriages on which the ink ejection head is mounted is the ink receiving position. The image forming apparatus according to claim 9 or 10, wherein the driving unit is controlled so as to be located at. At least one of the plurality of carriages is equipped with the image forming operation unit having a plurality of first ink ejection heads for ejecting inks of a plurality of basic colors.
At least one of the plurality of carriages is equipped with the image forming operation unit having a second ink ejection head for ejecting ink of an auxiliary color other than the plurality of basic colors.
The ejection control means includes a first mode in which ink is ejected by the first ink ejection head and the second ink ejection head, and the second mode in which ink is ejected by the first ink ejection head. The image according to any one of claims 9 to 11, wherein the ink is ejected by the ink ejection head in one of the modes selected from the second mode in which the ink is not ejected by the ink ejection head. Forming device. Each of the two or more carriages among the plurality of carriages is equipped with the image forming operation unit having the ink ejection head for ejecting ink of the same color.
The ejection control means is characterized in that the ink ejected from each of the ink ejection heads of the two or more carriages is superimposed on the recording medium and landed on the recording medium on the above-mentioned mounting surface. The image forming apparatus according to any one of claims 9 to 12. Each of at least two carriages among the plurality of carriages is equipped with the image forming operation unit having the ink ejection head for ejecting ink of the same color.
The ejection control means ejects ink that has not been ejected from the ink ejection head of one of the at least two carriages to the recording medium on the above-mentioned mounting surface, among the at least two carriages. The image forming apparatus according to any one of claims 9 to 13, wherein the ink is complemented by the ink ejected from the ink ejection head of any one of the carriages. Each of at least two carriages among the plurality of carriages is equipped with the image forming operation unit having the ink ejection head for ejecting ink of the same color.
Each of the ink ejection heads is provided with a plurality of nozzles for ejecting ink at predetermined intervals in an arrangement direction orthogonal to the movement direction of the carriage along the movement path.
The invention according to any one of claims 9 to 14, wherein the ink ejection heads of each of the at least two carriages are arranged so that the positions of the nozzles in the arrangement direction are different from each other. Image forming device. The ink ejection head ejects ink that is cured by irradiating with ultraviolet rays.
Claims 9 to 15 are characterized in that at least a part of the plurality of carriages is equipped with the image forming operation unit having an ultraviolet irradiation unit that irradiates the ink ejected on the recording medium with ultraviolet rays. The image forming apparatus according to any one of the above. Claims 1 to 16 are characterized in that at least a part of the plurality of carriages is equipped with the image forming operation unit having a functional liquid application unit that applies a predetermined functional liquid to the recording medium. The image forming apparatus according to any one of the above. It is characterized by providing a transport unit that transports the recording medium in the transport direction by moving the pre-described placement surface of the pre-described placement member in a transport direction that intersects the movement direction of the carriage along the movement path. The image forming apparatus according to any one of claims 1 to 17. A plurality of carriages each equipped with a mounting member having a mounting surface on which the recording medium is mounted, an image forming operation unit that performs an operation related to image formation on the recording medium on the previously described mounting surface, and the above. A support member that reciprocally supports a plurality of carriages along a predetermined movement path passing over the above-mentioned mounting surface, and a drive unit that independently moves each of the plurality of carriages along the movement path. It is a method of driving a carriage in an image forming apparatus equipped with.
The movement path includes a first region and a second region on the end side of the movement path with respect to the first region.
The driving method is the case where there are at least two moving carriages among the plurality of carriages and any adjacent pair of carriages among the plurality of carriages is in the first region. A carriage characterized by including a drive control step for controlling the drive unit so that the distance between the pair of carriages is larger than the distance between the pair of carriages when the pair of carriages is in the second region. Driving method.

Images