JP7419777B2 - Image forming device and cooling method - Google Patents

Description

The present invention relates to an image forming apparatus and a cooling method.

In recent years, inkjet image forming apparatuses that eject ink from the nozzles of inkjet heads (hereinafter simply referred to as heads) have become popular as devices for recording (forming) high-definition images on various recording media such as paper and fabric. is widely used.

Conventionally, inkjet image forming apparatuses use ink, ink tanks, heads, and transport rotating bodies such as drums and belts on which paper is placed and transported, in order to prevent defects and ensure productivity and image quality. , performs temperature control (monitoring, adjustment, etc.) of various parts, etc.

Among the above, temperature control of the transport rotor is closely related to the temperature of the paper placed on the transport rotor, and is an important matter along with paper temperature management. More specifically, the temperature of the paper is determined by the temperature (thermal energy) of the conveying rotor on which the paper is placed, which is propagated to the paper until the image forming process, that is, until ink is ejected from the head. That changes.

If the temperature of the paper is not appropriate during image formation, the spreadability of ink (dots) ejected from the head and landed on the paper may deteriorate, resulting in a decrease in image quality.

Specifically, if the temperature of the paper deviates from the target temperature when the ink lands (image formation), it becomes impossible to ensure the spread or uniformity of the ink dots on the paper, and the printed image deteriorates. Quality may deteriorate.

Therefore, when executing a print job, the inkjet image forming apparatus controls the temperature of the transport rotor to an appropriate temperature so that the temperature of the paper placed on the transport rotor falls within an allowable range from the target temperature. There are many models that have

For example, in an inkjet image forming apparatus described in Patent Document 1, a conveyance drum is proposed in which the printing cylinder (conveyance rotating body) is made of an aluminum alloy, and the heat capacity is reduced to facilitate temperature control.

JP 2017-7308 Publication

However, in the technology described in Patent Document 1, the temperature of the conveying rotor increases due to an external temperature increase factor, such as using an energy ray curing ink that is cured by irradiating energy rays such as UV (ultraviolet light). In this case, the conveyance rotating body cannot be efficiently cooled, and as will be described later, there is a problem that it is necessary to secure waiting time for waiting (printing stoppage), etc.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus and a cooling method that can efficiently cool a conveying rotor whose temperature has increased due to external factors.

The image forming apparatus according to the present invention includes:
a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a plurality of suction holes formed on the placement surface;
a suction unit that suctions the recording medium to the mounting surface by suctioning air from the suction hole;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
a cooling air supply unit that supplies the cooling air to the chamber;
Equipped with
The cooling air supply section is arranged to face the placement surface, and supplies the cooling air so that it flows from the chamber to the flow path .
Further, the image forming apparatus according to the present invention includes:
a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a heating unit that heats the conveying rotary body so that the temperature of the conveying rotary body becomes a set temperature;
Equipped with
The set temperature varies depending on the type of recording medium.
Further, the image forming apparatus according to the present invention includes:
a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
Equipped with
A plurality of the chambers are arranged in a direction of the rotation axis of the conveying rotor,
Each of the chambers is connected to a tube constituting the flow path.
Further, the image forming apparatus according to the present invention includes:
a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
Equipped with
A plurality of the chambers are arranged in a circumferential direction of the transport rotating body,
Each of the chambers is connected to a tube constituting the flow path,
In the plurality of chambers corresponding to the area where the recording medium is placed, when the cooling air is switched to flow in the chamber on the front end side in the transport direction, the cooling air is distributed in the chamber on the rear end side in the transport direction. In the chamber, air is sucked by the suction section.
Further, the image forming apparatus according to the present invention includes:
a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
Equipped with
When the recording medium is not being transported by the transporting rotor, the cooling air is supplied to all chambers arranged on the transporting rotor according to the measurement result of a temperature measurement unit that measures the temperature of the transporting rotor. supply

The cooling method according to the present invention includes:
While rotating a transport rotary body having a mounting surface on which the recording medium can be mounted, transporting the recording medium placed on the mounting surface,
attracting the recording medium to the mounting surface by suctioning air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. In the cooling method, the operation of sucking the air and the operation of circulating the cooling air are switched,
In the case of the operation of circulating the cooling air, the cooling air flows from a chamber disposed inside the conveying rotary body and communicating with the plurality of suction holes to a flow path disposed on a side surface of the conveying rotary body and communicating with the chamber. In this way, the cooling air is supplied from a cooling air supply section disposed opposite to the mounting surface .
Furthermore, the cooling method according to the present invention includes:
While rotating a transport rotary body having a mounting surface on which the recording medium can be mounted, transporting the recording medium placed on the mounting surface,
attracting the recording medium to the mounting surface by suctioning air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. In the cooling method, the operation of sucking the air and the operation of circulating the cooling air are switched,
A plurality of chambers arranged inside the conveying rotary body and communicating with the plurality of suction holes are arranged in a plurality in a circumferential direction of the conveying rotary body,
Each of the chambers is connected to a tube that is arranged on a side surface of the conveyance rotating body and constitutes a flow path that communicates with each of the chambers,
In the plurality of chambers corresponding to the area where the recording medium is placed, when the cooling air is switched to flow in the chamber on the front end side in the transport direction, the cooling air is distributed in the chamber on the rear end side in the transport direction. Air is being sucked into the chamber.
Furthermore, the cooling method according to the present invention includes:
While rotating a transport rotary body having a mounting surface on which the recording medium can be mounted, transporting the recording medium placed on the mounting surface,
attracting the recording medium to the mounting surface by suctioning air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. In the cooling method, the operation of sucking the air and the operation of circulating the cooling air are switched,
When the recording medium is not being transported by the transporting rotor, the cooling air is supplied to all chambers arranged on the transporting rotor according to the measurement result of a temperature measurement unit that measures the temperature of the transporting rotor. supply

According to the present invention, it is possible to efficiently cool the conveying rotating body whose temperature has increased due to external factors.

FIG. 1 is a side view illustrating a schematic configuration of an inkjet image forming apparatus according to an embodiment. 2 is a block diagram for explaining the main functions of the inkjet image forming apparatus of FIG. 1. FIG. It is a figure explaining the structure of the inside of a conveyance drum, and parts around it. FIGS. 4A and 4B are cross-sectional views for explaining the state of the conveyance drum during and after image formation in the conventional configuration. 5A and 5B are cross-sectional views for explaining the state of the conveyance drum during and after image formation according to the characteristic configuration of this embodiment. FIGS. 6A and 6B are schematic diagrams for explaining other configuration examples in this embodiment. 5B is a diagram for explaining still another configuration example of the present embodiment, and is a longitudinal cross-sectional view in a case where the cooling air flow direction is configured to be opposite to the example of FIG. 5B. FIG. It is a figure explaining still another example of a composition of this embodiment, and is a cross-sectional view showing an example where a plurality of chambers of a conveyance drum are arranged in a row in the rotation axis (width) direction. 3 is a flowchart illustrating characteristic processing of the present embodiment.

Hereinafter, an inkjet image forming apparatus according to the present embodiment will be described in detail with reference to the drawings.

FIG. 1 is a side view showing a schematic configuration of a transport drum type inkjet image forming apparatus 1 according to the present embodiment. Further, FIG. 2 is a block diagram showing the main functional configuration of the inkjet image forming apparatus 1. As shown in FIG.

As shown in FIG. 1, this inkjet image forming apparatus 1 includes an image forming apparatus main body 300 that includes a paper feeding section 11 that feeds (feeds) a recording medium P, a paper transport section 2, an image forming section 3, etc. and a paper ejecting section 28 that ejects the recording medium P on which an image is formed. The inkjet image forming apparatus 1 also includes an energy ray irradiation unit 60 downstream of the image forming unit 3, which will be described later, in the transport direction (see also FIG. 2).

Further, as shown in FIG. 2, the inkjet image forming apparatus 1 includes a data input section 10 into which various data related to a print job are input and stored, and a control section 40 that controls the entire inkjet image forming apparatus 1.

Referring to FIG. 1, the paper feed section 11 includes a paper feed tray 111 that stores the recording medium P, and a medium supply section 112 that transports and supplies the recording medium P from the paper feed tray 111 to the image forming section 3. .

The paper feed tray 111 is a plate-shaped member on which one or more recording media P can be placed. The paper feed tray 111 is provided so as to move up and down according to the amount (number of sheets) of recording media P placed on the paper feed tray 111, and in the vertical movement direction, the uppermost recording medium P is the medium feeder. It is held at the position where it is transported by the section 112.

The medium supply unit 112 includes a ring-shaped belt whose inner side is supported by two rollers, and rotates the rollers with the recording medium P placed on the belt, thereby transferring the recording medium P to the paper feed tray 111. The image forming apparatus is transported from the image forming apparatus into the main body 300 of the image forming apparatus.

The image forming apparatus main body 300 has a large-diameter (in this example, triple cylinder) transport drum 53, a transfer roller 52, and a plurality of heads 31 to 36 arranged as a paper transport section 2 that transports the recording medium P. It includes an image forming section 3, an energy ray irradiation section 60, and a plurality of transport rollers 56 to 59.

Among the above, the transport drum 53 corresponds to the "transport rotating body" of the present invention.

Further, in the above-mentioned "triple cylinder", the circumferential length (one round size) of the transport drum 53 is a size that can simultaneously hold three recording media P having the maximum length that can be used in this inkjet image forming apparatus 1. It means something.

In addition, as another example of the conveyance drum 53, for example, a four-fold cylinder or a five-fold cylinder may be used. Hereinafter, the above-mentioned transport drum 53 may be referred to as a "drum".

Among the above, a transport switching unit 25 (see FIG. 2) that switches the transport path or transport destination of the recording medium P is mainly constituted by claws, which will be described later, provided on the transport drum 53 and the transport rollers 56 to 59. .

The image forming apparatus main body 300 also includes an image forming section 3 in which a plurality of inkjet heads described later are arranged, and an image forming section 3 for curing and fixing an image (ink image) formed on the recording medium P. An energy ray irradiation unit 60 is provided.

Furthermore, the image forming apparatus main body 300 includes a paper reversing section 26 for reversing the recording medium P and feeding it out. In this example, the function of the paper reversing section 26 is mainly realized by the cooperative operation of the conveyance roller 59 and a swing arm section 51b, which will be described later.

The delivery roller 52 delivers the recording medium P transported by the medium supply section 112 of the paper feed section 11 to the transport drum 53. The delivery roller 52 includes a claw portion 52a that can be switched between open and closed states under the control of the control unit 40 in order to hold the recording medium P on its conveying surface.

The delivery roller 52 is provided at a position between the medium supply section 112 of the paper supply section 11 and the conveyance drum 53, and picks up one end of the recording medium P conveyed from the medium supply section 112 by holding it with a swing arm section 51f. At the same time, the recording medium P is held by the claw portion 52a and rotated clockwise as shown by the arrow in FIG.

The conveyance drum 53 holds the recording medium P on a cylindrical outer circumferential curved surface (conveyance surface) 53e, and has a rotating shaft extending in a direction perpendicular to the paper surface of FIG. 1 (hereinafter referred to as the "orthogonal direction"). By rotating around 53d (see FIG. 3, etc.), the recording medium P is conveyed in the conveyance direction (counterclockwise direction indicated by the arrow in FIG. 1) along the conveyance surface 53e.

In order to hold the recording medium P on the conveyance surface 53e, the conveyance drum 53 includes claw portions 53a, 53b, 53c, and an air suction portion (such as a paper suction blower 70 as a “suction portion”), which will be described later with reference to FIG. 4A and the like. ).

The three claws 53a, 53b, and 53c provided on the conveyance drum 53 are arranged at the same intervals as the circumferential lengths of the delivery roller 52 and the conveyance rollers 56, 57, and 58. The recording medium P is held on the conveyance surface 53e of the conveyance drum 53 by having its end pressed by one of the claws 53a to 53c and being attracted to the conveyance surface by the air suction section.

The claws 53a, 53b, and 53c of the transport drum 53 hold one end (the leading edge in the transport direction, hereinafter simply referred to as "leading edge") of the recording medium P that is delivered from the claw part 52a of the upstream delivery roller 52 at a predetermined position. It plays the role of holding one end of the recording medium P, and eventually the entire recording medium P, on the conveying surface 53e by pressing with a pressing force. Furthermore, when the above-mentioned pressing state is released (moves in the opening direction), these claw portions 53a, 53b, and 53c move the leading edge of the recording medium P held on the transport surface 53e to the claws of the transport roller 56 on the downstream side. It plays the role of handing over the information to the section 56a.

The claw portions 53a, 53b, and 53c of the conveyance drum 53 are switched between an open state and a closed state under the control of the control unit 40. Specifically, the claws (53a, 53b, 53c) are closed at the timing when the leading edge of the recording medium P is transferred from the claw part 52a of the upstream delivery roller 52, so that the leading edge of the recording medium P is transferred. hold. Further, the claw portions (53a, 53b, 53c) are opened at the timing when the leading edge of the recording medium P is transferred to the downstream conveyance roller 56, so that the recording medium is attached to the claw portion 56a of the downstream conveyance roller 56. Hand over the tip of P.

The paper transport section 2 (see FIGS. 1 and 2) has a transport drum motor (not shown) for rotating the above-mentioned transport drum 53, and drives the transport drum motor under the control of the control section 40 to transport the paper. The recording medium P is transported by rotating the drum 53 by an angle proportional to the amount of rotation of the transport drum motor. The transport drum 53, which serves as a transport rotating body, plays the role of transporting the recording medium P so as to face the nozzle surfaces of the inkjet heads (31 to 36).

The inkjet heads (hereinafter also simply referred to as "heads") 31 to 36 emit ink on an ink ejection surface facing the conveying surface of the conveying drum 53 at appropriate timings according to the rotation of the conveying drum 53 holding the recording medium P. An image is formed by ejecting ink onto the recording medium P from the provided nozzle openings. These heads 31 to 36 are arranged such that their ink ejection surfaces and the transport surface 53e of the transport drum 53 are separated by a predetermined distance.

In the example shown in Figure 1, each ink corresponds to yellow (Y), light magenta (LM), magenta (M), light cyan (LC), cyan (C), and black (K) from the upstream side in the transport direction. Six heads 31, 32, 33, 34, 35, and 36 are arranged in the order of colors Y, LM, M, LC, C, and K at predetermined intervals from the upstream side in the conveyance direction of the recording medium P. ing.

Note that the number of heads, that is, the number of colors used, the arrangement of colors, etc., are not limited to those described above, and are arbitrary. That is, in the inkjet image forming apparatus 1 of this embodiment, the number of heads can be less than or equal to 5 or more than 7 depending on the type of ink (color) used.

Although not shown, in one specific example, each head (31 to 36) includes a plurality of recording elements each having a pressure chamber for storing ink, a piezoelectric element provided on the wall of the pressure chamber, and a nozzle. It is provided. In this recording element, when a drive signal that causes the piezoelectric element to perform a deforming operation is input, the pressure chamber is deformed by the deformation of the piezoelectric element, the pressure within the pressure chamber changes, and ink is ejected from a nozzle communicating with the pressure chamber.

In this example, it is assumed that ultraviolet (UV) curing ink is ejected from each of the heads 31 to 36. Note that the ink ejected from the heads 31 to 36 is not limited to this, and may be of a property that can be dried or hardened by irradiation with other energy rays such as infrared rays or electron beams.

Referring to FIG. 2, the inkjet image forming apparatus 1 includes a control section 40 that controls the entire apparatus, a data input section 10, an image forming section 3 including a head driving section 30, an energy ray irradiation section 60, and a temperature detection section. 80, etc.

Of these, the data input section 10 includes an input interface, memory, etc. connected to an external device such as a PC (not shown). Here, as the memory, for example, an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may also be used in combination.

The data input unit 10 acquires (inputs and stores) data related to print jobs (job instructions, image data of images to be printed, various setting data, etc.) from an external device under the control of the control unit 40, and inputs and stores data related to print jobs. The image data is output to the head drive unit 30 when executing.

As described above, the image forming section 3 includes a plurality of heads 31 to 36 that eject ink of different colors, and a head driving section 30 that drives these heads.

The head drive unit 30 responds by supplying drive signals to each head (31 to 36) to deform the piezoelectric element in accordance with the image data at appropriate timing under the control of the control unit 40. An amount of ink corresponding to the pixel value of the image data is ejected from the nozzles of the heads (31 to 36).

The control unit 40 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), which are not shown.

Among the above, the CPU reads various control programs and setting data stored in the ROM, stores them in the RAM, and executes the programs to perform various calculation processes. Further, the CPU centrally controls the overall operation of the inkjet image forming apparatus 1.

RAM provides working memory space for the CPU and stores temporary data. Note that the RAM may include nonvolatile memory.

The ROM stores various control programs executed by the CPU, setting data, and the like. Note that a rewritable nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used instead of the ROM.

The energy ray irradiation unit 60 has a light emitting unit arranged across the width of the transport drum 53 in the orthogonal direction. The energy ray irradiation unit 60 irradiates the recording medium P placed on the conveyance drum 53 with energy rays such as ultraviolet rays from a light emitting unit, and ink ejected onto the recording medium P from the heads (31 to 36). By applying a predetermined energy to the ink, the ink on the recording medium P is cured and fixed.

On the downstream side of the energy ray irradiation unit 60 in the transport direction, a transport roller 56 facing the transport drum 53, a transport roller 57 facing the transport roller 56, transport rollers 58 and 59 facing the transport roller 57, and a transport roller 58 facing the transport roller 58 are provided. Opposing belt conveyance sections 280 are provided. Further, on the downstream side of the conveyance roller 59 in the conveyance direction, a swing arm section 51b is provided to hold and take up the rear end of the recording medium P conveyed from the conveyance roller 59.

As described above, the conveyance roller 59 and the swing arm section 51b play the role of the paper reversing section 26 (see also FIG. 2) that reverses the front and back of the recording medium P in the traveling direction, as well as the front and back sides.

Further, the above-described conveyance rollers 56, 57, 58, and 59 are each provided with claw portions 56a, 57a, 58a, and 59a that can be opened and closed under the control of the control unit 40.

The above-mentioned claws of the conveyance drum 53, conveyance roller 56, and the like form part of a conveyance switching section 25 (see FIG. 2) for switching the conveyance direction of the recording medium P.

The belt conveyance section 280 has a ring-shaped conveyance belt whose inner side is supported by three rollers. The belt conveyance section 280 conveys the recording medium P received from the conveyance rollers 57 and 58 using a conveyance belt, and sends it out to the paper discharge section 28 .

The paper discharge section 28 has a plate-shaped paper discharge tray 281 on which the recording medium P sent out from the image forming apparatus main body 300 by the belt conveyance section 280 is placed.

Referring to FIG. 2, the temperature detection unit 80 of the inkjet image forming apparatus 1 includes a plurality of non-contact temperature sensors (hereinafter simply referred to as temperature sensors), and outputs the measurement results of the temperature sensors to the control unit 40. .

In one specific example, the temperature sensor of the temperature detection unit 80 includes a first thermistor that detects infrared rays emitted from an object to be measured, and a second thermistor that measures ambient temperature for temperature compensation, By calculating the outputs of these two thermistors, the temperature of the object is measured. Thus, the temperature detection section 80 outputs the temperature of the object measured by each temperature sensor to the control section 40 as a detection signal. The paper temperature detection section 80 corresponds to the "temperature measurement section" of the present invention.

In this embodiment, one of the plurality of temperature sensors is disposed at a position facing the surface of the conveyance drum 53 downstream of the above-mentioned delivery roller 52 and upstream of the Y head 31 (hereinafter referred to as " (referred to as "first temperature sensor").

According to the first temperature sensor arranged in this manner, the image forming unit 3 generates an image on the recording medium P fed from the paper feeding unit 11 or conveyed from the paper reversing unit 26 when a print job is executed. It is possible to measure the temperature before the ink image is formed (the ink image is ejected). Further, according to the first temperature sensor, the surface temperature of the transport drum 53 can also be measured when the recording medium P is not placed.

Moreover, another one of the plurality of temperature sensors is arranged at a position near the downstream side of the energy ray irradiation unit 60 described above (hereinafter referred to as a "second temperature sensor"). According to the second temperature sensor, the temperature of the recording medium P after an image is formed by the image forming unit 3 (the ink head used) and irradiated with energy rays by the energy ray irradiating unit 60 during execution of a print job. can be measured. Further, according to the second temperature sensor, when the recording medium P is not placed, the surface temperature of the transport drum 53 can also be measured by the second temperature sensor.

Then, the control unit 40 executes various temperature-related controls, such as the temperature of the transport drum 53, based on the detection signals output from the respective temperature sensors arranged as described above.

In the image forming apparatus 1 having such a configuration, operations related to image formation are performed as described below under the control of the control section 40.

When executing a print job, the control unit 40 drives and controls the transport drum motor so as to start rotation of the drum, that is, rotation of the transport drum 53. Subsequently, the control unit 40 controls the paper feeding unit 11 (medium supply unit 112, etc.) to start feeding the recording medium P. Further, the control section 40 operates the air suction section (suction section) at an appropriate timing.

With this control, the recording medium P fed from the paper feeding section 11 passes through the medium feeding section 112 and the transfer roller 52, and is transferred to one of the conveying drums 53 rotating counterclockwise in FIG. The tip of the sheet in the conveying direction is held by the claws (53a to 53c) while being conveyed.

Here, the back surface of the recording medium P is suctioned through a large number of suction holes (gaps) provided on the conveyance surface 53e of the conveyance drum 53 by the operation of the air suction section (suction section), so that the recording medium P is attached to the conveyance surface 53e. While being attracted, it is stably transported according to the rotation of the transport drum 53.

Next, when performing single-sided printing, the control unit 40 performs a process of setting the conveyance switching unit 25 (opening/closing state of each claw portion described above) to the paper ejection side, and sets the conveyance switching unit 25 (the open/closed state of each claw portion described above) to the paper ejection side. are sequentially driven, ink is ejected from the corresponding heads, and an image (ink image) is formed on the recording medium P.

Subsequently, the control section 40 drives and controls the energy ray irradiation section 60 to perform a process of irradiating the recording medium P on which the ink image is formed with energy rays. Thereafter, the control unit 40 controls the leading edge of the recording medium P held on the conveyance drum 53 to be delivered to the conveyance rollers 56, 58, and the belt conveyance unit 280 in this order, so that the printing is completed on the recording medium P. P is conveyed to the paper discharge section 28.

Thereafter, the control unit 40 discharges the recording medium P and stops rotating the cylinder, and then ends the process. In this way, the recording medium P on which a full-color image is formed is stacked on the paper discharge tray 281 of the paper discharge section 28 .

On the other hand, when performing double-sided printing, the control section 40 sets the conveyance switching section 25 (see FIG. 2) to the paper reversal side.

Subsequently, the control unit 40 performs the same control as described above to irradiate the recording medium P on which an ink image (image) is formed with energy rays, and then the recording medium P is held on the transport drum 53. After the leading edge of the recording medium P is sequentially delivered to each of the claws (56a, 57a, 59a) of the conveyance rollers 56, 57, and 59, a process of reversing the recording medium P is performed.

Specifically, the control unit 40 holds the leading end of the recording medium P in the conveying direction (progressing direction) with the claw portion 59a of the conveying roller 59, and causes the conveying roller 59 to move the recording medium P clockwise in FIG. Carry out the movement of transport.

Subsequently, when the rear end of the recording medium P comes to a position facing the swing arm section 51b, the control section 40 rotates the swing arm section 51b while rotating the swing arm section 51b counterclockwise in FIG. At the same time as closing the claw portion (not shown) provided at the tip, control is performed to open the claw portion 59a of the conveyance roller 59. Through this operation, the recording medium P is transferred from the conveyance roller 59 to the swing arm section 51b.

Next, the control section 40 rotates the swing arm section 51b clockwise in FIG. Control is performed to open a claw (not shown) at the tip of the swing arm section 51b and to close a claw (any one of 53a to 53c) of the transport drum 53. Through this operation, the front and back sides of the recording medium P are reversed, and then the recording medium P is conveyed toward the image forming section 3 by the conveyance drum 53.

After this, the same operation as in the case of single-sided printing described above is performed, so that the recording medium P on which a full-color image is formed on the back side (second side) is conveyed to the paper ejection section 28, and the recording medium P is transported to the paper ejection tray 281. loaded on top.

Next, referring mainly to FIGS. 3 and 4 (FIGS. 4A and 4B), the configuration of the air suction section (suction section) and the like in the conventional configuration will be described.

Here, FIG. 3 is a diagram illustrating the configuration of the internal and surrounding parts of the conveyance drum 53, and FIGS. 4A and 4B illustrate the state etc. during paper suction (when executing the image forming process) and after executing the process. It is a figure for explaining.

Regarding the two double-headed arrows shown in FIG. 3, the upper arrow A1 is the suction area where the recording medium P is sucked by the air suction unit (suction unit), and the lower arrow A2 is the non-suction area where the recording medium P is not sucked. The suction areas are each shown.

Of the above, the suction area A1 faces the image forming unit 3 (each ink 31 to 36), and is an image forming area where an ink image is ejected (that is, an image is formed), and the energy beam irradiating unit 60 generates energy. Contains the irradiation area where the line is irradiated.

As shown in FIGS. 3 and 4A, the transport drum 53 has a hollow structure, and below (inside) the transport surface 53e is a recording medium P (hereinafter simply referred to as paper) to be used. A chamber 531 is formed having a width slightly smaller than the maximum width of the chamber 531.

As shown in FIG. 3, three chambers 531 (531L, 531M, 531N) are arranged between the two claws of the transport drum 53 (for example, between the claws 53c and 53a). Among these chambers, the first chamber 531L has a longer length along the paper conveyance direction. The length of this chamber 531L corresponds to the length (size in the transport direction) of the paper having the minimum length that can be used in the inkjet image forming apparatus 1.

Further, as shown in FIG. 4A, side plates 55, 55 that hold the rotation shaft 53d of the conveyance drum 53 are arranged on the front side (left side in FIG. 4A) and back side (right side in the same figure) of the apparatus. . Further, a substantially ring-shaped switching plate 54 is arranged between the side plate 55 and the side surface of the conveyance drum 53 on the back side of the apparatus. Of these, while the conveyance drum 53 rotates around a rotating shaft 53d, the switching plate 54 is configured not to rotate.

Specifically, the switching plate 54 has an insertion hole formed therein through which the rotation shaft 53d of the conveyance drum 53 is inserted, and a spring 551 provided between the switching plate 54 and the side plate 55 on the back side of the apparatus allows the conveyance drum 53 biased toward the side.

Furthermore, a communication opening 541 that forms part of a flow path for generating negative pressure in the chamber 531 of the transport drum 53 is formed on the surface of the switching plate 54 facing the transport drum 53 .

As shown in FIG. 3, the communication openings 541 are formed in multiple rows (three rows in this example) in the shape of arcuate grooves over a wide range on the side surface of the switching plate 54. Specifically, the communication opening 541 is connected to the number of chambers 531 used for paper having the maximum usable length (three in this example) and the position of the switching plate 54 corresponding to the position of the suction area A1. is formed.

As shown in FIG. 4, a tube 70a connected to a paper suction blower 70 serving as a source of negative pressure is fixed to each communication opening 541. Note that the paper suction blower 70 has a known configuration including a fan (blade), a motor, and the like, so a detailed description thereof will be omitted.

On the other hand, on the conveyance surface 53e of the conveyance drum 53, a sheet-like member (hereinafter referred to as a sheet) that forms the outer surface of the chamber 531 and has a large number of small holes or gaps is arranged (see also FIG. 4B). Air can circulate through the sheet. On the other hand, a communication hole 531a, which forms part of a flow path for generating negative pressure in the chamber 531, is formed in the surface of the transport drum 53 facing the sheet (bottom surface of the chamber 531).

Further, as shown in FIG. 4A, a connection hole 532a connected to the communication opening 541 of the switching plate 54 is formed on one side of the conveyance drum 53, that is, the side facing (rubbing) the switching plate 54. . Inside the transport drum 53, a tube 532 having a substantially L-shaped outer shape is provided, one end of the tube 532 is fixed to a connection hole 532a, and the other end of the tube 532 is connected to a communication hole 531a of the chamber 531 described above. is fixed to.

According to this configuration, from the conveyance of the recording medium P to the printing process (see FIG. 4A), the communication hole 532a of the conveyance drum 53 is connected to the communication opening 541 in the switching plate 54, and the communication hole 532a is connected as a flow path. (See also the arrow in the suction area A1 in FIG. 3).

Therefore, during this period (that is, until the leading edge of the paper passes through the suction area A1), the suction pressure (negative pressure) generated from the paper suction blower 70 is applied to the pipe 532 in the transport drum 53 and the communication hole of the corresponding chamber 531. By being propagated through 531a, the air pressure in chamber 531 decreases.

That is, the chamber 531 acts as a lid for the chamber 531 (each suction hole) on the conveying surface 53e by sucking (suctioning) the air inside the chamber 531 as suction air from the communication hole 531a. The paper being carried is attracted to and held by the transport surface 53e of the transport drum 53.

Thereafter, the paper on which images have been formed by the heads (31 to 36) and irradiated with energy rays by the energy ray irradiation section 60 is conveyed toward the paper discharge section 28 as described above in the case of single-sided printing. Ru. In addition, when double-sided printing is performed, after the front-back reversal operation is performed as described above, it is again supplied to the conveyance drum 53, but it is temporarily separated from the conveyance drum 53, and during that time, the other conveyance rollers 56, 57, 59.

In any case, in the non-suction area A2 shown in FIG. 3, there is usually no need to suck the paper, so as shown in FIG. 4B, the pipe 532 of the transport drum 53 and the connection hole 532a are It is not connected (communicated) with the communication opening 541 of , and no flow path connected to the paper suction blower 70 is formed.

In other words, the communication opening 541 is not provided in the lower area of the switching plate 54 corresponding to the non-suction area A2 where there is no need to suck paper (see FIGS. 3 and 4B), and therefore the non-suction area The conveyance surface 53e (chamber 531 and suction hole) of the conveyance drum 53 located at A2 is not affected by the negative pressure generated by the paper suction blower 70.

On the other hand, conventionally, a heater for heating, a fan for cooling (blower), etc. (not shown), etc. are arranged at appropriate positions in the non-suction area A2, and the temperature of the conveyance drum 53 is adjusted under the control of the control unit 40. was.

Thus, when a print job is executed, paper is fed (feeded) from the paper feed unit 11 toward the paper transport unit 2 of the image forming apparatus main body 300 based on the control signal from the control unit 40, and the paper is sucked. Blower 70 operates.

Subsequently, the leading edge of the paper is held by one of the claws (53a to 53c) of the transport drum 53, and the other part of the recording medium P is attracted by the negative pressure generated in the chamber 531 of the transport drum 53. , is stably held on the conveying surface 53e of the conveying drum 53.

This paper suction state continues until the stage of image formation by ink ejection from the heads (31 to 36) described above and energy ray irradiation by the energy ray irradiation section 60, after which the chamber 531 sucking the paper continues. The process ends by entering the non-suction area A2 (see FIG. 3).

By the way, in many inkjet image forming apparatuses, in order to prevent malfunctions and breakdowns in advance and to ensure the quality of printed images, ink, ink tanks, heads, and drums and belts that carry and transport paper are Temperature control (management, adjustment, etc.) is executed for various parts such as the transport rotating body (in this example, the transport drum 53).

Among the above, temperature control of the conveying rotor, that is, the conveying drum 53, is closely related to the temperature of the paper being placed and conveyed, and is an important matter along with paper temperature management. More specifically, the temperature of the paper is determined by the temperature (thermal energy) of the transport drum 53 until the image forming process, that is, until the ink is ejected from the heads (31 to 36). It changes as it is propagated to the paper.

If the temperature of the paper is not appropriate during image formation, the ink (dots) ejected from the heads (31 to 36) onto the paper and landed on the paper may not spread well, resulting in a decrease in image quality.

Specifically, if the temperature of the paper deviates from the target temperature when the ink lands (image formation), it becomes impossible to ensure the spread or uniformity of the ink dots on the paper, and the printed image deteriorates. Quality may deteriorate.

For this reason, inkjet image forming apparatuses generally control the temperature of a rotating transport body such as a cylinder to an appropriate temperature when executing a print job, thereby adjusting the temperature of the paper placed on the rotating transport body within a range from the target temperature. Many models try to stay within this range.

On the other hand, as mentioned above, in the conventional technology such as Patent Document 1, the temperature of the conveying rotor increases due to an external temperature increase factor such as using energy ray curable ink and curing it by irradiating energy rays. In this case, there was a problem in that the conveyance rotating body could not be efficiently cooled.

In other words, when energy ray-curable ink is ejected onto paper and irradiated with energy rays, curing heat (an external temperature increase factor) is generated during the curing of the ink, and the energy of this curing heat causes the transport rotation through the paper. By being transmitted to the body, the temperature of the conveying rotor increases.

In order to return (cool) the temperature of the conveyance rotary body in which such a temperature increase has occurred to an appropriate range, in one specific example of the conventional configuration, for example, the downstream side of the energy ray irradiation unit 60 in the conveyance direction (for example, A cooling fan was provided nearby), and the transport drum 53 was cooled by air blown from the fan.

However, such a configuration does not have sufficient ability (performance) to quickly return (cool) the temperature of the transport rotor, which has risen due to the above-mentioned curing heat, to an appropriate range. For this reason, with conventional technology, it is necessary to wait until the temperature of the weight, that is, the transport rotor, returns to the appropriate range before stopping printing, or to install a large-scale cooling device. There were also technical issues from the viewpoint of productivity and space saving.

In view of the above-mentioned problems, the present embodiment adopts the configuration described below to efficiently and quickly move the transport drum 53 while meeting the demands for printing productivity and space saving. The aim is to achieve efficient cooling and ensure the quality of printed images.

Here, FIGS. 5A and 5B are cross-sectional views for explaining the state of the conveyance drum during and after image formation according to the characteristic configuration of this embodiment, and are surrounded by broken lines in FIG. 5A. The portion shown in FIG. 2 shows the characteristic configuration of this embodiment.

As can be seen by comparing with FIGS. 4A and 4B showing the conventional configuration described above, in this embodiment, a new communication opening (542) is formed on the lower side of the switching plate 54, and the communication opening 542 is provided with a new communication opening (542). A drum cooling blower 75 and a pipe 75a are additionally provided to supply air for cooling the transport drum 53 (hereinafter simply referred to as "cooling air").

Note that although only one communication opening 542 of the switching plate 54 is shown in FIG. A plurality of rows (three rows in this example) are provided in an arc shape so as to connect with the connection hole 532a of the pipe 532.

In relation to the present invention, the switching plate 54 in which the new communication opening 542 is mainly provided among the portions surrounded by broken lines in FIG. 5A corresponds to the "switching portion" in the present invention.

Note that the "switching section" in the present invention is not limited to such a mechanical configuration, but also controls turning on/off of the drum cooling blower 75, the flow path, or the flow path, as described later with reference to FIGS. 8 and 9, for example. It may be a control configuration related to opening degree adjustment. In this embodiment, the above-mentioned switching plate 54 and control section 40 correspond to the "switching section" in the present invention.

Generally speaking, the "switching section" in the present invention switches the functions of the suction holes and chamber 531 in the transport drum 53 into the "suction (adsorption) of the recording medium P" function and the "cooling of the transport drum 53" function, that is, the "cooling air cooling" function. Includes mechanical or control configurations for switching in and out.

Generally speaking, in this embodiment, the cooling air supplied from the drum cooling blower 75 through the pipe 75a is transferred by utilizing the movement of the internal flow path (existing pipe 532 and connection hole 532a) as the transport drum 53 rotates. The configuration is such that cooling air is supplied to the chamber 531 through the flow path (see FIG. 5B).

In this way, according to this embodiment, the functions of the suction holes and the chamber 531 are switched by utilizing the existing paper suction flow path (pipe 532, etc.) as a distribution path for cooling air, thereby saving space. can meet the demands of

Of the configurations described above, the drum cooling blower 75 and the pipe 75a correspond to the "cooling air supply section" of the present invention. As the drum cooling blower 75, a known blower including a fan, a motor for rotating the fan, and the like (ie, an air blower) can be used.

The temperature of the cooling air supplied from the drum cooling blower 75 is not particularly limited, but is desirably lower than the temperature of the transport drum 53 when the energy ray irradiation section 60 is operated, and furthermore, the temperature of the cooling air supplied from the drum cooling blower 75 is preferably lower than the temperature of the transport drum 53 when the energy ray irradiation section 60 is operated. temperature) is desirable. For this reason, the drum cooling blower 75 may be configured to include a known temperature adjustment section such as a Peltier device, for example.

According to this configuration, the cooling air supplied to the chamber 531 does not stagnate within the chamber 531 unlike the conventional configuration, and while the corresponding chamber 531 is located in the non-suction area A2 (see FIG. 3), The fluid continuously flows from the chamber 531 to the outside of the transport drum 53 through the flow path.

In this way, when the chamber 531 is located in the non-suction area A2, cooling air is continuously supplied (circulated) to the chamber 531 through the corresponding flow path. stagnation of cooling air can be prevented.

Therefore, according to the present embodiment, while maintaining the function of sucking paper into the suction hole and chamber 531 located in the suction area A1, the transport drum 53, which has risen to a high temperature due to energy beam irradiation, is moved to the non-suction area A2. It can be cooled quickly. Therefore, according to the present embodiment, it becomes easier to manage and control the temperature of the conveyance drum 53 by the control unit 40, and as a result, the quality of the printed image can be maintained at a high level.

In the above-described configuration example shown in FIG. It plays the role of making the fluid flow from the flow path) side to the chamber 531 side.

As another example, a configuration may be adopted in which the cooling air is circulated from the chamber 531 side to the tube 532 (flow path) side, and such a modification will be described later with reference to FIG. 7.

Next, a modification of the above-described embodiment will be described.

In the embodiment described above, the drum cooling blower 75 is provided with a temperature adjustment section. On the other hand, from the viewpoint of supporting the drum cooling blower 75 or the need to lower the temperature of the cooling air more quickly, as shown in FIG. It may also be configured to be added to the tube 75a).

Such a configuration may be adopted, for example, when the drum cooling blower 75 is installed near the paper suction blower 70 due to installation space constraints. That is, since the air exhausted from the paper suction blower 70 has a relatively high temperature (see the black arrow in FIG. 6A), the air flowing into the nearby drum cooling blower 75 (see the hatched arrow in FIG. 6A) ) may be higher than expected.

In the embodiment described above, a dedicated blower (drum cooling blower 75) for cooling the transport drum 53 is provided separately from the paper suction blower (70). As another configuration example, as shown in FIG. 6B, the drum cooling blower 75 is not provided, and the exhaust flow of the existing paper suction blower 70 (see the added pipe 71, etc.) is cooled by the above-mentioned cooling unit 76, Such cooling air may be outputted to the pipe 75a for cooling the conveyance drum 53.

In this case, compared to the configuration of FIG. 6A, since the drum cooling blower 75 is not required instead of adding the pipe 71, it can be realized at lower cost. However, the cooling unit 76 may need to have higher cooling performance than that shown in FIG. 6A.

In the embodiment described above, the cooling air ejected from the drum cooling blower 75 is supplied to the chamber 531 via the communication opening 541 of the switching plate 54 and the pipe 532 (flow path) in the transport drum 53. The configuration is such that the temperature of the conveyance drum 53 and, in turn, the recording medium P is adjusted.

As another configuration example, as shown in FIG. 7, the direction in which the cooling air flows may be reversed. In the example shown in FIG. 7, for example, a known temperature control fan (for example, a Peltier fan) having a temperature control function is used as the cooling unit 76A, and the air outlet (not shown) of the temperature control fan is connected to the conveyor drum. 53 (conveyance surface 53e). Furthermore, a suction blower 75A having the same function as the paper suction blower 70 described above is disposed in the above-mentioned tube 75a, for example. Here, the suction blower 75A corresponds to the "cooling air suction section" of the present invention.

According to this configuration, the cooling air blown from the cooling unit 76A (see the five white arrows in FIG. 7) passes through the conveyance surface 53e of the conveyance drum 53 and fills the chamber 531. Then, due to the suction action of the suction blower 75A, the air in the chamber 531 is sucked into the suction blower 75A through the communication hole 531a, the pipe 532, the communication opening 542 of the switching plate 54, and the pipe 75a.

Thus, according to the configuration shown in FIG. 7, unlike the conventional configuration described above with reference to FIG. Smooth distribution towards 75A.

Furthermore, in the conventional configuration, in order to increase the cooling efficiency of the conveyance drum 53, attempts have been made to increase the output of the fan (air blower), that is, the amount of air supplied from the fan to the conveyance drum 53 per unit time. However, in this case, the air is reflected by the conveyance surface 53e of the conveyance drum 53 and diffused into the surroundings, and the diffused air causes problems (for example, misalignment of the paper held on the conveyance surface 53e and effects on image quality). There was a risk that

On the other hand, in the configuration shown in FIG. 7, which allows cooling air to flow, reflection and diffusion of the cooling air can be suppressed, so the flow velocity of the cooling air can be increased compared to the conventional configuration. As a result, the temperature of the transport drum 53 can be adjusted (cooled) in a short time.

Furthermore, as a modification of the configuration shown in FIG. 7, a heat exchanger is provided in which a normal fan is provided in place of the temperature control fan (such as a Peltier fan) to adjust (cool) the temperature of the air taken in and exhausted by the suction blower 75A. It is also possible to provide a configuration in which air cooled by the heat exchanger is provided and the air cooled by the heat exchanger is supplied to the above-mentioned fan.

According to the configuration examples and their modifications shown in FIGS. 5 to 7 described above, when the conveyance drum 53 rotates, the suction holes and the chamber 531 in the non-suction area A2 cool the conveyance drum 53 (flow of cooling air). ), and the paper is sucked (negative pressure is formed) in the suction hole and chamber 531 in the suction area A1.

In other words, in relation to one recording medium P placed on the conveyance drum 53 and conveyed when a print job is executed, when the chamber 531L located on the leading edge side of the paper in the conveyance direction comes to the non-suction area A2, the corresponding In the chamber 531L, cooling air is circulated through the suction hole, and in other chambers 531 that follow, a "switching section" is configured (i.e., the mechanical structure is changed) so that air is sucked from the suction hole. ).

In contrast, by configuring the "switching section" to include a control element as described below, functions corresponding to various uses can be provided to the conveying surface 53e (suction hole) of the conveying drum 53. and chamber 531).

In the embodiment described above, a plurality of chambers 531 of the transport drum 53 (3×3=9 in the example shown in FIG. 3) are arranged in the circumferential direction of the transport drum 53, that is, in the transport direction of the recording medium P. It is assumed that the configuration is as follows. On the other hand, the configuration of the arrangement of the chambers 531 (in other words, the manner in which they are divided or sectioned) is not limited to this, but in the direction perpendicular to the above, that is, the direction of the rotation axis 53d of the transport drum 53 (width direction). It is also possible to arrange (divide) so that a plurality of them are lined up.

FIG. 8 shows an example of a transport drum 53A including a plurality of chambers 531A arranged in a plurality in a circumferential direction of the transport drum 53 and in a plurality in a row in a direction of the rotating shaft 53d. Note that the chamber 531A shown in FIG. 8 is a modification of the chamber corresponding to the chamber 531L in FIG. 3, and the other chambers 531M and 531N in FIG. 3 are similarly divided.

As shown in FIG. 8, the chamber 531A of the conveyance drum 53A is a divided chamber that is arranged (divided or divided) in a plurality (three in this example) in the width direction of the rotating shaft 53d or the paper to be placed. 531-1, 531-2 and 531-3. A communication hole 531a is formed in each of these divided chambers (531-1 to 531-3).

In line with this aspect of arrangement or division (division), in the transport drum 53A, the pipes 532 (532A) provided therein also have a different configuration, as can be seen by comparing with FIG. 5B and the like. That is, the pipe 532A is configured to branch into the number of divisions (three in this example) in order to connect to the communication holes 531a provided in each division chamber.

In addition, a known electromagnetic valve (not shown) is disposed in each branched flow path connected to each communication hole 531a in the pipe 532A. Each electromagnetic valve opens and closes according to the control of the control unit 40 to individually open and close the flow path and adjust the opening degree for each divided chamber 531 (531-1 to 531-3).

Overall, in the modified example shown in FIG. 8, (3×3×3=) 27 chambers are arranged on the transport drum 53, and each chamber can be switched open/closed and the opening degree can be controlled. A flow path is provided.

By providing such a configuration, various controls and uses can be performed as described below.

In one specific example, when using a recording medium P whose size in the transport direction is shorter than the maximum usable length, the control unit 40 controls the opening and closing of the solenoid valves to open and close three chambers 531L to 531N along the circumferential direction. , and the individual divided chambers 531 (531-1 to 531-3) can have various functions.

That is, in the suction area A1 (see FIG. 3), the control unit 40 uses some of the three chambers 531L, 531M, and 531N (for example, only two, the chamber 531L and one subsequent chamber 531M) for paper suction. In order to use the chamber 531N, the flow path (that is, the solenoid valve) of the remaining chamber 531N is controlled to be closed at a predetermined timing.

On the other hand, in the non-suction area A2, the control unit 40 controls one chamber 531N that is in a closed state at a predetermined timing so that all three chambers 531L, 531M, and 531N are used for supplying cooling air. Controls the flow path (solenoid valve) to open.

In this case, the paper suction blower 70 generates negative pressure only in the chambers 531L and 531M corresponding to the position where the paper is placed (see suction area A1 in FIG. 3) to attract the paper, and The drum cooling blower 75 can supply cooling air to the chamber 531 located in the non-suction area A2, regardless of the position where the recording medium P is placed.

By performing such control, it is possible to suppress the power consumption of the paper suction blower 70 by using the chamber 531 as much as necessary for paper suction while maintaining the cooling air supply capacity.

As another example, ink is ejected exclusively to the center of the recording medium P, and the curing heat of the ink due to energy ray irradiation is transmitted to the center of the transport drum 53, so that the temperature rise of the transport drum 53 varies widely. Cases may occur where the direction is different.

In such a case, the amount of cooling air supplied to each divided chamber 531-1 to 531-3 in the non-suction area A2 (see FIG. 3) can be changed by adjusting the opening degree of the solenoid valve under the control of the control unit 40. In this case, the amount of cooling air supplied to the divided chamber 531-2 can be made larger than that to the other divided chambers (531-1, 531-3).

Alternatively, when using a recording medium P whose size in the width direction is small, the control unit 40 controls the opening and closing of the solenoid valve to allow the recording medium P to be It can also be used to absorb.

In FIG. 8, a configuration example in which the chamber 531 is divided into three parts along the axial direction of the transport drum 53A has been described. On the other hand, the number of divisions of the chamber 531 is not limited to this, and may be divided into two, or may be divided into four or more.

In addition, in FIG. 8, the pipe 532A connected to one connection hole 532a on the side surface of the transport drum 53A is connected to each of the divided chambers (531-1, 531-2, 531-3) along the width direction. It was configured to branch to form a flow path.

As still another example, when the recording medium P is not being transported by the transport drum 53 (transporting rotor), the control unit 40 uses a paper temperature detection unit 80 that measures the temperature of the transport drum 53 (transporting rotor). Control to supply cooling air to all the chambers 531 arranged on the transport drum 53 (transport rotor) by operating the drum cooling blower 75 (cooling air supply unit) according to the measurement results of the temperature measurement unit (temperature measurement unit) You may do so.

This is done in consideration of a case where the temperature of the transport drum 53 significantly increases during maintenance or due to an additional external temperature increase factor.

Hereinafter, with reference to the flowchart of FIG. 9, characteristic processing regarding the temperature control or cooling method of the conveyance drum 53 in this embodiment will be described. Note that the flowchart shown in FIG. 9 is based on the assumption that the ink ejected from each of the heads 31 to 36 is energy ray-curable ink such as UV, and the configuration example shown in FIG. 5 is used.

Further, the flowchart shown in FIG. 9 assumes a configuration in which a heating unit such as a heater is provided near the conveyance drum 53, as in the conventional case.

In other words, it is necessary to set different target temperatures for the temperature of the transport drum 53 depending on the type of recording medium P. In the above case, it is necessary to operate the heater (heating section) without operating the drum cooling blower 75 to heat the conveyance drum 53 to a set temperature according to the type of paper (basis weight, etc.).

Thus, with the start of execution of the print job, the control unit 40 starts monitoring the output (detection signal) of each temperature sensor in the temperature detection unit 80 described above (step S100). Further, the control unit 40 starts operation of the drum cooling blower 75 (cooling air supply unit) at an appropriate timing.

Next, the control unit 40 specifies (estimates) the temperature of the transport drum 53 based on the detection results of one or more temperature sensors that detect the surface temperature of the recording medium P being transported by the transport drum 53 ( Step S110).

In one specific example, the control unit 40 specifies (estimates) the temperature of the transport drum 53 from the detection result of the second temperature sensor described above and the basis weight of the paper used.

Alternatively, the control unit 40 also refers to the detection results of the first temperature sensor described above, and calculates the amount of temperature increase calculated from the surface temperature of each sheet of paper before image formation and immediately after irradiation with energy rays, and the amount of temperature increase of the paper used. The temperature of the conveyance drum 53 may be specified (estimated) from the basis weight.

In the next step S120, the control unit 40 determines whether the temperature (estimated value) of the transport drum 53 is within the target temperature range.

Here, if the control unit 40 determines that the temperature of the transport drum 53 is within the target temperature range (step S120, YES), it is determined that there is no need to operate either the drum cooling blower 75 or the heater (heating unit). Make a decision and finish the process.

On the other hand, if the control unit 40 determines that the temperature of the conveyance drum 53 is not within the target temperature range (deviates from the range) (step S120, NO), the process proceeds to step S125.

In step S125, the control unit 40 determines whether the specified (estimated) temperature of the conveyance drum 53 exceeds an upper limit value.

Here, when the control unit 40 determines that the specified (estimated) temperature of the conveyance drum 53 exceeds the upper limit value (step S125, YES), the process proceeds to step S130.

On the other hand, if the control unit 40 determines that the specified (estimated) temperature of the conveyance drum 53 does not exceed the upper limit value (step S125, NO), the control unit 40 determines that the temperature exceeds the lower limit value. Then, the process moves to step S140.

In step S130, the control unit 40 operates the drum cooling blower 75 to start supplying cooling air to the chamber 531 located in the non-suction area A2, and returns to step S110 described above.

On the other hand, in step S140, the control unit 40 operates the heating unit to heat the conveyance drum 53, and returns to step S110.

Thereafter, the control unit 40 determines that the temperature of the transport drum 53 specified (estimated) in step S110 has reached a temperature (a value within the target temperature range) corresponding to the type of recording medium P used for printing (step The process of step S125 and step S130 or step S140 described above is repeated until it is determined (S120, YES).

Then, when the control unit 40 determines that the estimated temperature of the conveyance drum 53 is within the target temperature range (step S120, YES), the process ends.

Note that if the determination result in step S125 after starting the operation of the drum cooling blower 75 is NO (the lower limit of the target temperature is exceeded), the control unit 40 controls the operation of the drum cooling blower 75 in step S140. Performs control to stop operation.

Further, if the control unit 40 determines that the temperature of the transport drum 53 still exceeds the upper limit value (higher than the target temperature) in the process of step S125 again, the control unit 40 performs the following control in step S130. .

That is, in step S130 again, the control unit 40 performs control to lower the temperature setting of the temperature adjustment unit or increase the wind speed of the blower unit in the drum cooling blower 75 in order to increase the cooling capacity of the drum cooling blower 75.

On the other hand, if the control unit 40 determines NO in step S125 (the temperature of the transport drum 53 has become lower than the target temperature), in order to lower the cooling capacity of the drum cooling blower 75, the control unit 40 performs temperature adjustment in step S140. Control may be performed to increase the temperature setting in the section or to decrease the wind speed in the blower section.

Thus, when the control unit 40 determines in step S120 that the temperature of the transport drum 53 has fallen within the target temperature range (step S120, YES), the process ends.

Note that the control unit 40 repeatedly executes each process in the flowchart of FIG. 9 as appropriate until the print job is finished. By repeatedly performing this process, temperature changes in the transport drum 53 during print job execution are suppressed as much as possible, and by keeping the temperature of the transport drum 53 constant, the image printed on the recording medium P is can maintain constant quality.

In general, the inkjet image forming apparatus 1 according to the present embodiment has a mounting surface (conveying surface 53e) on which the recording medium P can be placed, and rotates while rotating the recording medium P placed on the conveying surface 53e. A conveying drum 53 as a conveying rotating body for conveying, a paper suction blower 70 as a suction unit that attracts the recording medium P to the conveying surface 53e by suctioning air from a plurality of suction holes formed in the conveying surface 53e, Cooling air for cooling the conveyance drum 53 is circulated between the inside and outside of the conveyance drum 53 via the suction holes in an area of the conveyance surface 53e where the recording medium P is not placed. It includes a switching unit (switching plate 54, control unit 40, etc.) that switches between the operation of suctioning air and the operation of circulating cooling air.

From another point of view, the inkjet image forming apparatus 1 is a transporting body that carries the recording medium P on a transporting surface 53e (placing surface) that forms a part of the chamber 531 and transports it to the image forming section 3 or the like. A suction unit (paper suction blower 70, etc.) that connects to a pipe 532 (flow path) connected to the chamber 531 and generates negative pressure in the chamber 531 in order to attract the drum 53 and the recording medium P on the conveying surface 53e; A cooling air supply unit (such as a drum cooling blower 75) that supplies cooling air at a temperature lower than that of the conveyance drum 53 is provided to the chamber 531 located in an area where the recording medium P is not attracted by the suction unit. The section is configured to allow cooling air to flow through a pipe 532 (flow path).

According to the present embodiment having the above-described configuration, the phenomenon in which the cooling air stagnates inside or around the transport drum 53 is suppressed, and the cooling efficiency is improved. Therefore, according to the inkjet image forming apparatus 1 of the present embodiment, the transport drum 53 whose temperature has increased due to external factors such as energy ray irradiation can be quickly cooled, and the paper sheet placed on the transport drum 53 can be cooled quickly. By stabilizing the temperature of the paper, it is possible to ensure the quality of printed images on paper.

In the embodiments described above, the case where the present invention is applied to an inkjet image forming apparatus has been described. On the other hand, the characteristic configuration of each of the embodiments described above is, for example, an offset printing machine that transports a recording medium using a cylinder-shaped transport member, a thermal transfer type image forming apparatus that uses a printing cylinder (transport rotating body), etc. , it can be applied to various devices where problems similar to those of this embodiment may occur.

The embodiments described above have been described on the assumption that paper such as plain paper or coated paper is used as the recording medium P. On the other hand, as the recording medium P on which the ink image is formed, various media capable of fixing the ink that has landed on the surface, such as cloth or sheet-like resin, can be used.

The various configuration examples in the embodiments described above can be combined as appropriate or arbitrarily depending on necessity (for example, the relationship with surplus space), cost, purpose, etc.

In addition, the above-mentioned embodiments and configuration examples are merely examples of implementation of the present invention, and the technical scope of the present invention should not be interpreted to be limited by these. It is. That is, the present invention can be implemented in various forms without departing from its gist or main features.

1 Inkjet image forming device (image forming device)
2 Paper transport unit 3 Image forming unit 10 Data input unit 11 Paper feed unit 25 Transport switching unit 26 Paper reversing unit 28 Paper discharge unit 30 Head drive unit 31 to 36 Heads (image forming unit)
40 Control unit (switching unit)
51b, 51f Swing arm portion 52 Delivery roller 53, 53A Conveyance drum (conveyance rotating body)
53a, 53b, 53c Claw portion 53d Rotating shaft 53e Conveying surface (placing surface)
54 Switching plate (switching part)
55 Side plate 56, 57, 58, 59 Conveyance roller 60 Energy ray irradiation section 70 Paper suction blower (suction section)
70a pipe
71 Pipe 75 Drum cooling blower (cooling air supply section, blower section, temperature adjustment section)
75A Suction blower (cooling air suction part)
75a pipe 76 cooling section 76A cooling section 80 temperature detection section (temperature measurement section)
280 Belt conveyance unit 300 Image forming apparatus main body 531 (531L, 531M, 531N), 531A Chamber 531-1, 531-2, 531-3 Divided chamber 531a Communication hole 532, 532A Pipe (flow path)
532a Connection hole 541 Communication opening 542 Communication opening 551 Spring A1 Suction area (first rotation position)
A2 Non-suction area (second rotational position)
P Recording medium

Claims (26)

a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
a cooling air supply unit that supplies the cooling air to the chamber;
Equipped with
The cooling air supply unit is arranged to face the placement surface, and supplies the cooling air so as to flow from the chamber to the flow path.
Image forming device. The switching unit connects the opening to the suction unit to suck air from the chamber when the chamber is located at the first rotational position of the transport rotating body, and the switching unit connects the opening to the suction unit to suck air from the chamber, and the switching unit , switching between an action of sucking the air and an action of circulating the cooling air so that the cooling air is caused to flow into the chamber through the opening.
The image forming apparatus according to claim 1. The first rotational position includes an area where an image is formed on the recording medium adsorbed to the placement surface,
the second rotational position corresponds to a non-suction area where the recording medium is no longer attracted to the placement surface;
The image forming apparatus according to claim 2. comprising a cooling air suction unit that sucks the cooling air flowing into the flow path;
The image forming apparatus according to claim 1 . The cooling air supply section includes a blowing section that blows air,
comprising a control section that controls the air volume of the air blowing section;
The image forming apparatus according to any one of claims 1 to 4 . The cooling air supply section includes a temperature adjustment section,
comprising a control section that controls the temperature of the temperature adjustment section;
The image forming apparatus according to any one of claims 1 to 5 . comprising a heating unit that heats the conveying rotor so that the temperature of the conveying rotor becomes a set temperature;
The image forming apparatus according to any one of claims 1 to 6 . The set temperature varies depending on the type of recording medium,
The image forming apparatus according to claim 7 . a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a heating unit that heats the conveying rotary body so that the temperature of the conveying rotary body becomes a set temperature;
Equipped with
The set temperature varies depending on the type of recording medium,
Image forming device. an image forming unit that forms an image by discharging energy ray-curable ink onto the recording medium;
an energy ray irradiation unit that irradiates the ink ejected onto the recording medium with energy rays;
The image forming apparatus according to claim 1 . a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
Equipped with
A plurality of the chambers are arranged in a circumferential direction of the transport rotating body,
Each of the chambers is connected to a tube constituting the flow path.
The image forming apparatus according to claim 1 . a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
Equipped with
A plurality of the chambers are arranged in a direction of the rotation axis of the conveying rotor,
Each of the chambers is connected to a tube constituting the flow path.
The image forming apparatus according to claim 1 . a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
Equipped with
A plurality of the chambers are arranged in a direction of the rotation axis of the conveying rotor,
Each of the chambers is connected to a tube constituting the flow path.
Image forming device. a control unit that controls suction of air from the chamber corresponding to the recording medium adsorbed on the placement surface;
The image forming apparatus according to any one of claims 11 to 13 . The tube constituting the flow path is provided with a valve that adjusts the opening degree of the flow path to the corresponding chamber,
The control unit controls suction of air from the chamber corresponding to the recording medium adsorbed on the placement surface by switching opening and closing of the valve.
The image forming apparatus according to claim 14 . In the plurality of chambers corresponding to the area where the recording medium is placed, when the cooling air is switched to flow in the chamber on the front end side in the transport direction, the cooling air is distributed in the chamber on the rear end side in the transport direction. In the chamber, air is sucked by the suction section,
The image forming apparatus according to claim 11 . a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
Equipped with
A plurality of the chambers are arranged in a circumferential direction of the transport rotating body,
Each of the chambers is connected to a tube constituting the flow path,
In the plurality of chambers corresponding to the area where the recording medium is placed, when the cooling air is switched to flow in the chamber on the front end side in the transport direction, the cooling air is distributed in the chamber on the rear end side in the transport direction. In the chamber, air is sucked by the suction section,
Image forming device. a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
a cooling air supply unit that supplies the cooling air to the chamber;
a temperature measurement unit that measures the temperature of the recording medium being transported by the transport rotor or the transport rotor;
a control unit that controls a cooling operation by the cooling air supply unit according to the measured temperature;
The image forming apparatus according to any one of claims 1 to 17, comprising: The temperature measurement unit measures the temperature of the recording medium or the conveyance rotating body upstream of the image forming unit in the conveyance direction of the recording medium.
The image forming apparatus according to claim 18. The length of the outer periphery of the conveyance rotating body is a length that can convey a plurality of the recording media at the same time.
The image forming apparatus according to any one of claims 1 to 19. comprising a reversing unit for reversing the front and back of the recording medium upstream of the image forming unit in the transport direction of the recording medium and supplying the reverse to the transport rotating body;
The image forming apparatus according to any one of claims 1 to 20. When the recording medium is not being transported by the transporting rotor, the cooling air is supplied to all chambers arranged on the transporting rotor according to the measurement result of a temperature measurement unit that measures the temperature of the transporting rotor. supply,
The image forming apparatus according to any one of claims 1 to 21. a conveyance rotating body having a placement surface on which a recording medium can be placed, and conveying the recording medium placed on the placement surface while rotating;
a suction unit that attracts the recording medium to the mounting surface by sucking air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. a switching unit that switches between an operation of sucking the air and an operation of circulating the cooling air;
a chamber disposed inside the transport rotating body and communicating with the plurality of suction holes;
an opening of a flow path that is arranged on a side surface of the conveying rotor and communicates with the chamber;
Equipped with
When the recording medium is not being transported by the transporting rotor, the cooling air is supplied to all chambers arranged on the transporting rotor according to the measurement result of a temperature measurement unit that measures the temperature of the transporting rotor. supply,
Image forming device. While rotating a transport rotary body having a mounting surface on which the recording medium can be mounted, transporting the recording medium placed on the mounting surface,
attracting the recording medium to the mounting surface by suctioning air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. In the cooling method, the operation of sucking the air and the operation of circulating the cooling air are switched,
In the case of the operation of circulating the cooling air, the cooling air flows from a chamber disposed inside the conveying rotary body and communicating with the plurality of suction holes to a flow path disposed on a side surface of the conveying rotary body and communicating with the chamber. The cooling air is supplied from a cooling air supply unit disposed opposite to the mounting surface .
Cooling method. While rotating a transport rotary body having a mounting surface on which the recording medium can be mounted, transporting the recording medium placed on the mounting surface,
attracting the recording medium to the mounting surface by suctioning air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. In the cooling method, the operation of sucking the air and the operation of circulating the cooling air are switched,
A plurality of chambers arranged inside the conveying rotary body and communicating with the plurality of suction holes are arranged in a plurality in a circumferential direction of the conveying rotary body,
Each of the chambers is connected to a tube that is arranged on a side surface of the conveyance rotating body and constitutes a flow path that communicates with each of the chambers,
In the plurality of chambers corresponding to the area where the recording medium is placed, when the cooling air is switched to flow in the chamber on the front end side in the transport direction, the cooling air is distributed in the chamber on the rear end side in the transport direction. Air is sucked into the chamber,
Cooling method. While rotating a transport rotary body having a mounting surface on which the recording medium can be mounted, transporting the recording medium placed on the mounting surface,
attracting the recording medium to the mounting surface by suctioning air from a plurality of suction holes formed in the mounting surface;
Cooling air for cooling the conveying rotor is circulated between the inside and outside of the conveying rotor through the suction hole in an area of the placing surface where the recording medium is not placed. In the cooling method, the operation of sucking the air and the operation of circulating the cooling air are switched,
When the recording medium is not being transported by the transporting rotor, the cooling air is supplied to all chambers arranged on the transporting rotor according to the measurement result of a temperature measurement unit that measures the temperature of the transporting rotor. supply,
Cooling method.

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