Patent Description:
In an image forming apparatus such as a copier or a printer, a conveyance device that conveys a sheet is provided.

As such a conveyance device, there is a conveyance device that includes a conveyance belt to support a sheet on a surface thereof and convey the sheet and a guide to guide the sheet from or to the conveyance belt (see, for example, <CIT>). <CIT>, <CIT>, and <CIT> disclose background art to the invention.

Typically, a leading end of the guide is arranged in a non-contact manner with respect to the surface of the conveyance belt. However, when the distance between the leading end of the guide and the surface of the conveyance belt is excessively increased, there is a possibility that the sheet cannot be satisfactorily transferred between the guide and the conveyance belt. For this reason, the distance between the leading end of the guide and the surface of the conveyance belt is appropriately managed.

There is an endless conveyance belt that is wound around a plurality of support rollers and is endlessly formed by connecting both ends of a band-shaped belt so as to facilitate replacement work or maintenance work of components. In the case of such a conveyance belt, since there is a joint, the shape of the conveyance belt is non-uniform at a joint portion.

For example, in the case where the belt surface protrudes at the joint portion, the distance between the leading end of the guide and the belt surface to be large is set so that the leading end of the guide does not interfere with the protruding joint portion. However, in this case, since the distance between the guide and the conveyance belt becomes large particularly at a portion other than the joint, there is a possibility that the sheet enters between the guide and the conveyance belt, causing a paper jam or conveyance failure. In contrast, when the joint portion has a concave shape, the distance between the guide and the conveyance belt increases at the joint portion, so that the sheet might enter between the guide and the conveyance belt.

It is therefore an object of the present disclosure to reduce the distance between the surface of a conveyance member and the leading end of a guide even when the conveyance member is, for example, a conveyance belt having a joint.

In order to solve the above-described problem, according to an embodiment of the present disclosure, a conveyance device includes a conveyance belt, a guide, and a rotator. The conveyance belt has a conveyance surface with a joint, the conveyance belt to convey an object to be conveyed, with the object on the conveyance surface. The guide approaches the conveyance surface and guide the object from or to the conveyance belt.

The rotator contacts the conveyance surface. The guide displaces in a direction perpendicular to the conveyance surface, in conjunction with displacement of the rotator when the rotator contacts the joint.

According to another embodiment of the present disclosure, a drying device includes the conveyance device to convey the object to be conveyed and a dryer to dry the object to be conveyed.

According to still another embodiment of the present disclosure, an image forming apparatus includes an image forming device to form an image on a sheet and the conveyance device to convey the sheet.

According to still yet another embodiment of the present disclosure, a liquid discharge apparatus includes a liquid discharger to discharge liquid onto a sheet and the conveyance device to convey the sheet.

According to at least one embodiment of the present disclosure, even with the conveyance member including the joint, the distance between the surface of the conveyance member and the leading end of the guide can be reduced.

With reference to drawings, embodiments of the present disclosure are described in detail below. Note that identical reference numerals are assigned to identical components or equivalents and a redundant description of those components is appropriately simplified or omitted.

Hereinafter, an embodiment of the present disclosure will be described taking an example of a conveyance device mounted on an inkjet image forming apparatus. In the drawings for describing embodiments of the present disclosure, components such as members and constituent parts having the same function or shape are denoted by the same reference numerals as far as discriminable, and the description thereof will be omitted after once described.

First, a general arrangement of an inkjet image forming apparatus according to the present embodiment will be described with reference to <FIG>.

An inkjet image forming apparatus <NUM> illustrated in <FIG> includes a sheet supply device <NUM>, a pretreatment device <NUM>, an image forming device <NUM>, a drying unit <NUM>, a sheet reversing device <NUM>, and a sheet ejection device <NUM>.

The sheet supply device <NUM> supplies a sheet as a recording medium on which an image is formed, and includes a supply tray <NUM> to accommodate a plurality of sheets S, and a feeder <NUM> that separates and feeds the sheets S one by one from the supply tray <NUM>. The sheet S fed by the feeder <NUM> is supplied to the pretreatment device <NUM>.

The pretreatment device <NUM> applies a treatment liquid to the sheet S supplied from the sheet supply device <NUM>, and includes a treatment liquid applier <NUM> that applies the treatment liquid. The treatment liquid is, for example, a liquid having a function of aggregating ink, and is applied to the sheet S before image formation by the treatment liquid applier <NUM> for the purpose of enhancing an image quality such as preventing ink bleeding and assisting ink permeation. The sheet S to which the treatment liquid is applied is supplied to the image forming device <NUM>.

The image forming device <NUM> forms an image on the supplied sheet S. Specifically, the image forming device <NUM> includes a drum <NUM> as a first bearing rotator that rotates while bearing the sheet S on an outer peripheral surface thereof, a plurality of liquid discharge units 15C, <NUM>, 15Y, and <NUM> as a liquid discharger that discharges liquid ink onto the sheet S borne on the drum <NUM>, a transfer cylinder <NUM> as a second bearing rotator that transfers the sheet S supplied from the pretreatment device <NUM> to the drum <NUM>, and a transfer cylinder <NUM> as a third bearing rotator that transfers the sheet S from the drum <NUM> to an upstream conveyance belt <NUM> included in a drying device <NUM> described later. In the example illustrated in <FIG>, the liquid discharge unit 15C for cyan ink, the liquid discharge unit <NUM> for magenta ink, the liquid discharge unit 15Y for yellow ink, and the liquid discharge unit <NUM> for black ink are arranged in this order from an upstream side in a rotation direction of the drum <NUM> (conveyance direction of the sheet S). The arrangement of the liquid discharge units 15C, <NUM>, 15Y, and <NUM> is not limited to the order illustrated in <FIG>, and may be in any other order. A liquid discharge unit that discharges ink of a special color such as white, gold, and silver may be added as necessary.

When the sheet S is supplied from the pretreatment device <NUM> to the image forming device <NUM>, a leading end of the sheet S is gripped by a sheet gripper as a gripper included in the transfer cylinder <NUM>, and the sheet S is conveyed with the rotation of the transfer cylinder <NUM>. The sheet S is transferred to the drum <NUM> at a position where the transfer cylinder <NUM> and the drum <NUM> face each other. A sheet gripper as a gripper is disposed on the outer peripheral surface of the drum <NUM> in the same manner as the transfer cylinder <NUM>, and the leading end of the sheet S is gripped by the sheet gripper. A plurality of suction holes are dispersedly formed on the outer peripheral surface of the drum <NUM>, and airs flow sucked into the drum <NUM> from suction holes can be generated by a suction device. As a result, the sheet S is attracted by the outer peripheral surface of the drum <NUM> to be borne thereon. The sheet S is conveyed with the rotation of the drum <NUM> while being borne on the outer peripheral surface of the drum <NUM> by an attracting action of the sheet gripper and the air flow.

Then, when the sheet S on the drum <NUM> is conveyed to a position facing each of the liquid discharge units 15C, <NUM>, 15Y, and <NUM>, ink is discharged from each of the liquid discharge units 15C, <NUM>, 15Y, and <NUM> onto the sheet S. Each of the liquid discharge units 15C, <NUM>, 15Y, and <NUM> includes, for example, a head module <NUM> including a full-line head as illustrated in <FIG>. Specifically, the head module <NUM> includes a base <NUM> and a plurality of liquid discharge heads <NUM> alternately arranged on the base <NUM>. The liquid discharge heads <NUM> each includes a plurality of nozzle rows including a plurality of nozzles <NUM> arrayed in a sheet width direction (lateral direction in <FIG>) orthogonal to a sheet conveyance direction A.

As illustrated in <FIG>, when the sheet S is conveyed to a position facing each of the liquid discharge units 15C, <NUM>, 15Y, and <NUM>, discharge drive of each of the liquid discharge units 15C, <NUM>, 15Y, and <NUM> is controlled by a drive signal based on image information, and the ink is discharged from each of the liquid discharge units 15C, <NUM>, 15Y, and <NUM> onto the sheet S. As a result, an image corresponding to the image information is formed on the sheet S. The sheet S is transferred from the drum <NUM> to the transfer cylinder <NUM>, and then transferred from the transfer cylinder <NUM> to the upstream conveyance belt <NUM>.

The drying unit <NUM> includes the drying device <NUM> that heats the sheet S to dry the ink on the sheet S. The drying device <NUM> includes a first heating unit <NUM> that heats the sheet S borne on the transfer cylinder <NUM>, a second heating unit <NUM> that heats the sheet S again after the heating by the first heating unit <NUM>, the upstream conveyance belt <NUM> as a first conveyance member to which the sheet S is transferred from the transfer cylinder <NUM>, and a downstream conveyance belt <NUM> as a second conveyance member that conveys the sheet S on a downstream side in the sheet conveyance direction with respect to the upstream conveyance belt <NUM>. The first heating unit <NUM> and the second heating unit <NUM> are dryers that heat the sheet S to dry the ink, and the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM> form a conveyance device <NUM> that conveys the sheet S in the drying device <NUM>.

When the sheet S is borne on the transfer cylinder <NUM>, the sheet S is heated by the first heating unit <NUM>. While being heated on the transfer cylinder <NUM>, the sheet S is transferred from the transfer cylinder <NUM> to the upstream conveyance belt <NUM> at a position where the transfer cylinder <NUM> faces the upstream conveyance belt <NUM>. The sheet S is further transferred from the upstream conveyance belt <NUM> to the downstream conveyance belt <NUM>. When the sheet S reaches a position facing the second heating unit <NUM> along with the conveyance of the downstream conveyance belt <NUM>, the sheet S is heated by the second heating unit <NUM>. In this manner, the sheet S is heated by the first heating unit <NUM> and the second heating unit <NUM>, so that the drying of the ink on the sheet S is promoted.

The sheet reversing device <NUM> reverses the front side and the back side of the sheet S to convey to the image forming device <NUM> again in a case of duplex printing. Specifically, the sheet reversing device <NUM> includes a switchback conveyor <NUM> that conveys the sheet S in an opposite direction by a switchback system, and a duplex conveyor <NUM> that conveys the switch-backed sheet S to an upstream side from the transfer cylinder <NUM> in the sheet conveyance direction. In the case of forming images on both sides of the sheet S, after an image is formed on the front side of the sheet S in the image forming device <NUM>, the sheet S is conveyed to the sheet reversing device <NUM> after a drying process in the drying unit <NUM>, and conveyed in the opposite direction by the switchback conveyor <NUM>. The sheet S is conveyed to the upstream side from the transfer cylinder <NUM> through the duplex conveyor <NUM>. As a result, the sheet S is supplied to the image forming device <NUM> in a state of being reversed. Then, after an image is formed on the back side of the sheet S in the image forming device <NUM>, the sheet S is conveyed from the sheet reversing device <NUM> to the sheet ejection device <NUM> through the drying process by the drying unit <NUM>.

The sheet S on one side or both sides of which an image is formed is ejected to the sheet ejection device <NUM>. The sheet ejection device <NUM> includes an ejection tray <NUM> on which the ejected sheets S are stacked. When the sheet S is conveyed from the sheet reversing device <NUM> to the sheet ejection device <NUM>, the sheets S are sequentially stacked and placed on the ejection tray <NUM>.

An overall configuration of the drying device <NUM> according to the present embodiment is described below with reference to <FIG>.

As illustrated in <FIG>, the first heating unit <NUM> included in the drying device <NUM> includes a warm air generator <NUM>. The warm air generator <NUM> is disposed in a non-contact manner so as to face the outer peripheral surface of the transfer cylinder <NUM>. The warm air generator <NUM> is provided with a heater that generates hot air and a nozzle that blows the generated hot air as warm air toward the transfer cylinder <NUM>. By the warm air blown from the nozzle to the outer peripheral surface of the transfer cylinder <NUM>, the outer peripheral surface of the transfer cylinder <NUM> is warmed. As a result, the sheet S on the transfer cylinder <NUM> is heated, and an ink drying process is performed.

The warm air generator <NUM> can adjust the temperature of the warm air in the rage from room temperature to about <NUM> based on the temperature detected by a temperature detection sensor mounted thereon. The temperature of the warm air can be optionally set according to information such as the amount of liquid (ink) adhered to a sheet S and the type (material) of sheet. From the viewpoint of reducing waviness (cockling) of a sheet due to application of liquid such as ink, low-temperature warm air is preferably blown, for example, with the heater turned off.

As illustrated in <FIG>, the second heating unit <NUM> included in the drying device <NUM> includes a plurality of ultraviolet irradiators <NUM> arranged in the sheet conveyance direction A. The ultraviolet irradiators <NUM> are arranged above the downstream conveyance belt <NUM> so as to face the downstream conveyance belt <NUM>, and irradiates a sheet S conveyed by the downstream conveyance belt <NUM> with ultraviolet rays to heat the sheet S.

As illustrated in <FIG>, the ultraviolet irradiator <NUM> includes an irradiation surface 34a on which a plurality of granular ultraviolet-light-emitting diode (UV-LED) light emitting elements <NUM> are arranged. Since each UV-LED light emitting element <NUM> emits light with the same illuminance, the irradiation surface 34a uniformly emits light as a whole. As ultraviolet light (UV light), for example, one having a peak wavelength of <NUM> and a full width at half maximum of about <NUM> as the wavelength distribution is used. However, the peak wavelength and wavelength distribution of the UV light are not limited thereto.

As illustrated in <FIG>, the drying device <NUM> includes the conveyance device <NUM> including the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM>. The upstream conveyance belt <NUM> is wound and supported around a plurality of support rollers <NUM> in endless form. When at least one of the plurality of support rollers <NUM> functions as a drive roller, the upstream conveyance belt <NUM> rotates (circulates). Although the upstream conveyance belt <NUM> is supported by the two support rollers <NUM> in the present embodiment, in some embodiments, the number of support rollers <NUM> supporting the upstream conveyance belt <NUM> may be two or more. In the present embodiment, as the upstream conveyance belt <NUM>, a mesh belt or a plain-woven belt provided with a large number of holes on a conveyance surface (outer peripheral surface) 18a that holds the sheet S is used. The term "conveyance surface" as used herein means a portion forming a planar conveyance path, on which a sheet being an object to be conveyed is held or placed. The portion contacting the sheet is not necessarily a surface, and may be, for example, a mesh. A suction chamber <NUM> including a blower or a fan as a suction device is arranged inside the upstream conveyance belt <NUM>. As a result, when the suction chamber <NUM> is driven and air is sucked from a large number of holes on the conveyance surface 18a of the upstream conveyance belt <NUM>, the sheet S is attracted to the conveyance surface 18a by the sucked air. The upstream conveyance belt <NUM> rotates in a state in which the sheet S is attracted, so that the sheet S is conveyed downstream.

The downstream conveyance belt <NUM> arranged downstream from the upstream conveyance belt <NUM> in the sheet conveyance direction is basically configured in the same manner as the upstream conveyance belt <NUM>. In other words, the downstream conveyance belt <NUM> is endlessly wound around a plurality of support rollers <NUM>, and at least one of the support rollers <NUM> functions as a drive roller to rotate (circulate). In the present embodiment, the downstream conveyance belt <NUM> is supported by the two support rollers <NUM>. However, in some embodiments, the number of support rollers <NUM> supporting the downstream conveyance belt <NUM> may be two or more. A suction chamber <NUM> is disposed inside the loop of the downstream conveyance belt <NUM>. When the suction chamber <NUM> is driven and air is sucked from a large number of holes on a conveyance surface 19a of the downstream conveyance belt <NUM>, the sheet S is attracted to the conveyance surface 19a by the sucked air. When the downstream conveyance belt <NUM> rotates with the sheet S attracted on the conveyance surface 19a, the sheet S is conveyed downstream.

A mechanism for attracting the sheet S to the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM> is not limited to the mechanism using the airflow as described above, and may be an electrostatic attraction mechanism for attracting the sheet to the belt using static electricity. A grip unit such as a gripper may be disposed on each of the conveyance belts <NUM> and <NUM>, and the sheet may be gripped by the grip unit.

As illustrated in <FIG>, a guide <NUM> is arranged between the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM>. That is, the conveyance device <NUM> according to the present embodiment includes the guide <NUM> that guides the sheet S from the upstream conveyance belt <NUM> to the downstream conveyance belt <NUM> in addition to the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM>. The guide <NUM> is arranged close to the conveyance surfaces 18a and 19a of the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM>, respectively, so as not to come into contact with them.

The drying device <NUM> configured as described above operates as follows.

First, when the sheet S is borne on the transfer cylinder <NUM>, the heat of the transfer cylinder <NUM> heated by the warm air generator <NUM> to the sheet S is applied to the sheet S and the sheet S is heated. As a result, the drying of the ink on the sheet S is promoted, and a first drying process is performed on the sheet S. The sheet S is transferred to the upstream conveyance belt <NUM> while being heated on the transfer cylinder <NUM>, and is conveyed by the upstream conveyance belt <NUM>. Thereafter, the sheet S is guided to the downstream conveyance belt <NUM> via the guide <NUM>, and is conveyed by the downstream conveyance belt <NUM>. When the sheet S reaches a position facing each ultraviolet irradiator <NUM> along with the conveyance of the downstream conveyance belt <NUM>, each ultraviolet irradiator <NUM> irradiates the sheet S with ultraviolet rays to heat the sheet S. Therefore, a second drying process is performed on the sheet S.

In this manner, in the drying device <NUM> according to the present embodiment, after the first drying process of heating the sheet S by the heat of the transfer cylinder <NUM> heated by the warm air generator <NUM> is performed, the second drying process of heating the sheet S by the ultraviolet rays from each ultraviolet irradiator <NUM> is performed. Thus, the ink on the sheet S can be effectively dried.

In the drying device <NUM> according to the present embodiment, since the ultraviolet irradiator <NUM> is used as a heating device for performing the second drying process, only an image portion (portion to which the ink is applied) of the sheet S can be selectively heated. As a result, the temperature of a non-image portion (portion to which no ink is applied) of the sheet S does not rise more than necessary, and excessive evaporation of moisture contained in the non-image portion can be reduced, so that waviness of the sheet S can be reduced.

As a heating device for heating the sheet S, in addition to the ultraviolet irradiator, an infrared irradiator for emitting infrared rays to heat an object such as an IR lamp may be used, but the ultraviolet irradiator is more preferable than the infrared irradiator from the viewpoint of appropriately maintaining the moisture amount of the sheet after the drying process. In fact, when a test was conducted in which the sheet was heated using the infrared irradiator and the ultraviolet irradiator and surface temperature of the sheet after heating was measured, there was a large difference in temperature of the non-image portion of the sheet after the drying process between a case of using the infrared irradiator and a case of using the ultraviolet irradiator. In general, in order to dry aqueous ink, it is necessary to raise the temperature of the image portion of the sheet to about <NUM>, so that in this test, it was heated so that the temperature of the image portion reached <NUM> in both cases of using the infrared irradiator and using the ultraviolet irradiator. As a result, in a case of using the infrared irradiator, the temperature of the non-image portion of the sheet reached <NUM>, whereas in a case of using the ultraviolet irradiator, the temperature of the non-image portion of the sheet was <NUM>, which was lower by <NUM> than that in a case of using the infrared irradiator. When the water content of the non-image portion was measured, the water content of the non-image portion decreased from <NUM>% to <NUM>% in the case of using the infrared irradiator, whereas the water content of the non-image portion merely decreased from <NUM>% to <NUM>% in the case of using the ultraviolet irradiator. That is, it was confirmed that the moisture content of the non-image portion can be kept high in the case of using the ultraviolet irradiator as compared with the case of using the infrared irradiator. From this result also, it can be said that the ultraviolet irradiator is more preferable than the infrared irradiator in order to appropriately maintain the moisture amount of the sheet after the drying process.

In the drying device <NUM> according to the present embodiment, a belt endlessly wound around a plurality of support rollers is used as the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM>. As such endless belt, in addition to a seamless belt including no j oint, a belt including a joint in a part in the rotation direction can be used. In particular, the type that can be separated at a joint portion has an advantage that the belt can be easily removed at the time of replacement work or maintenance work of the belt and other components. Therefore, in the present embodiment, a separable belt including the joint in a part in the rotation direction is used as the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM>.

Specifically, as illustrated in <FIG>, both ends 90b and 90c of the belt <NUM> are connected using a connecting member <NUM> such as a pin to make the belt <NUM> endless. In a case of such belt <NUM>, the belt <NUM> can be easily attached by connecting both ends 90b and 90c of the belt <NUM> after winding the belt <NUM> around a plurality of support rollers, and conversely, the belt <NUM> can be easily detached by releasing the connection between both ends 90b and 90c. In <FIG>, a case where a mesh-shaped belt is used is taken as an example, but a flat belt may be used. As a material of the belt, a material having heat resistance such as a fluorine-based material or a silicone-based material is preferable.

As described above, in a case of the belt that can be separated at the joint portion, there is an advantage of being excellent in replacement work or maintenance work of components. However, such belt has the following disadvantage in relation to the guide.

<FIG> is a diagram illustrating a positional relationship between the belt <NUM> including a joint J and a guide <NUM> arranged close to the belt <NUM>.

The guide <NUM> illustrated in <FIG> is a member for receiving an object conveyed by the belt <NUM> and guiding the object to the downstream side. Therefore, a leading end 80a of the guide <NUM> is arranged close to a conveyance surface (outer peripheral surface) 90a of the belt <NUM> so that the object to be conveyed can be favorably received from the belt <NUM>. In the case where the object to be conveyed is a thin member such as a sheet, it is preferable to minimize a distance D between the leading end 80a of the guide <NUM> and the conveyance surface 90a of the belt <NUM> so that the object (sheet) does not enter between the guide <NUM> and the belt <NUM>.

However, as illustrated in <FIG>, in the case of the belt <NUM> including the joint J, since a connecting member <NUM> connecting both ends of the belt <NUM> is inserted at the joint J, a portion of the joint J protrudes in a direction perpendicular to the conveyance surface 90a (toward the outer peripheral surface of the belt <NUM>) than any other portion. Therefore, the guide <NUM> needs to be arranged with a large distance D with respect to the conveyance surface 90a secured so as not to interfere with the portion of the joint J. Therefore, the belt including the joint has a problem of difficulty in reducing the distance between the leading end of the guide and the conveyance surface of the belt as compared with a seamless belt including no joint.

Therefore, in the present embodiment, the guide has the following configuration so that the distance between the surface of the conveyance belt and the leading end of the guide can be reduced even with the conveyance belt including the joint. Hereinafter, a configuration of the guide according to an embodiment of the present disclosure will be described in detail.

<FIG> is a perspective view illustrating a configuration of a guide <NUM> included in the conveyance device <NUM> according to the present embodiment and a peripheral portion thereof.

As illustrated in <FIG>, the guide <NUM> is formed of a plate member extending in a width direction of the upstream conveyance belt <NUM> or the downstream conveyance belt <NUM>. The guide <NUM> includes a guide surface 29b arranged substantially flush with the conveyance surface 18a of the upstream conveyance belt <NUM> and the conveyance surface 19a of the downstream conveyance belt <NUM> (upper surfaces of the conveyance belts <NUM> and <NUM> in <FIG>), and the sheet S is guided from the upstream conveyance belt <NUM> to the downstream conveyance belt <NUM> along the guide surface 29b. Here, the "width direction of the upstream conveyance belt <NUM> or the downstream conveyance belt <NUM>" means a direction orthogonal to the sheet conveyance direction A along the conveyance surface of the conveyance belt. In the present embodiment, since the guide <NUM> is longitudinally formed in the width direction of the conveyance belt, a direction in which the guide <NUM> extends in the width direction of the conveyance belt is referred to as a "longitudinal direction" of the guide <NUM> in the following description.

The width of the guide <NUM> in the longitudinal direction is set to be equal to or larger than the width of a conveyance region E in which the sheet S is conveyed and equal to or smaller than each of the width of the upstream conveyance belt <NUM> and the width of the downstream conveyance belt <NUM>. As the material of the guide <NUM>, a commonly-used material can be applied as long as the sliding resistance with respect to the sheet S is small. Examples of the material used for the guide <NUM> include, but not limited to, stainless used steel (SUS), an electrogalvanized steel sheet such as silver top, and an uneven steel sheet. Further, ribs may be disposed on the guide <NUM>. The material of the guide <NUM> is preferably the same as that of the upstream conveyance belt <NUM> or the downstream conveyance belt <NUM>. In addition, it is preferable that the surface roughness and the hardness of the guide <NUM> are substantially the same as those of the upstream conveyance belt <NUM> or the downstream conveyance belt <NUM>.

As illustrated in <FIG>, a pair of frame members <NUM> that supports the conveyance belts <NUM> and <NUM>, and the support rollers <NUM> and <NUM> in addition to the guide <NUM> is disposed on both ends in the longitudinal direction of the guide <NUM>. The guide <NUM> is attached to each frame member <NUM> so as to be swingable in a direction of an arrow B in <FIG>. Specifically, the guide <NUM> is rotatably supported around a support shaft <NUM> arranged on a rear end 29c side of the guide <NUM>. As a result, the leading end 29a (end on a side opposite to the rear end 29c) of the guide <NUM> is configured to be swingable in a direction to approach and a direction to move away from the conveyance surface 18a of the upstream conveyance belt <NUM>.

A pair of rotators <NUM> in contact with the conveyance surface 18a of the upstream conveyance belt <NUM> is disposed at both ends in the longitudinal direction of the guide <NUM>. Each rotator <NUM> is arranged outside a conveyance region E where the sheet S is conveyed so as not to come into contact with the sheet S to be conveyed. In a state in which each rotator <NUM> is in contact with the conveyance surface 18a of the upstream conveyance belt <NUM>, the leading end 29a of the guide <NUM> is arranged to approach (so as not to be in contact with) the conveyance surface 18a of the upstream conveyance belt <NUM>.

<FIG> is a cross-sectional view of the guide <NUM> as seen in the longitudinal direction thereof.

As illustrated in <FIG>, the guide <NUM> is attached to and held by a movable stay <NUM>, which is a guide holding member. The movable stay <NUM> includes the support shaft <NUM>, which is the swing center of the guide <NUM>, and when the movable stay <NUM> rotates about the support shaft <NUM>, the guide <NUM>, together with the movable stay <NUM>, swings in a direction intersecting the conveyance surface 18a of the upstream conveyance belt <NUM> (direction of arrow B in <FIG>). The movable stay <NUM> is rotatably attached to a fixed stay <NUM> as a supporting member via the support shaft <NUM>. In the present embodiment, the support shaft <NUM> is attached to the fixed stay <NUM> so as to be movable in the axial direction (so as to have a backlash) so that even if the guide <NUM> and the movable stay <NUM> thermally expand in the longitudinal direction by the heat of the drying device <NUM>, the support shaft <NUM> does not interfere with the fixed stay <NUM> to limit the swing of the guide <NUM> or damage the members. The fixed stay <NUM> is fixed so as not to be movable with respect to the frame member <NUM>.

A rotator holding member <NUM> that rotatably holds the rotator <NUM> is attached to the movable stay <NUM>. The rotator <NUM> is arranged so as to protrude toward the upstream conveyance belt <NUM> beyond the leading end 29a of the guide <NUM>. Therefore, in a state in which the rotator <NUM> is in contact with the conveyance surface 18a of the upstream conveyance belt <NUM>, the leading end 29a of the guide <NUM> is arranged so as not to be in contact with the conveyance surface 18a.

A spring <NUM> as a biasing member is attached between the rotator holding member <NUM> and the fixed stay <NUM>. The spring <NUM> is provided to bias the rotator <NUM> toward the upstream conveyance belt <NUM>. As a result, the rotator <NUM> is held in a state of being in contact with the conveyance surface 18a of the upstream conveyance belt <NUM>.

<FIG> is a plan view illustrating a configuration of one end side in the longitudinal direction of the guide <NUM>.

As illustrated in <FIG>, a hole 29d into which a fixing member <NUM> such as a screw is inserted is disposed on one end side in the longitudinal direction of the guide <NUM>. The hole 29d is also disposed on an opposite end side (the other end side in the longitudinal direction) of the one end side in the longitudinal direction of the guide <NUM> illustrated in <FIG>. When the fixing member <NUM> is inserted into each hole 29d and attached to the movable stay <NUM>, the guide <NUM> is fixed to the movable stay <NUM>.

The hole 29d is formed of a long hole extending along the guide surface 29b in a direction (vertical direction in <FIG>) intersecting the longitudinal direction of the guide <NUM>. Therefore, when the guide <NUM> is moved in a direction in which the hole 29d extends, a fixing position of the guide <NUM> can be changed to an upward direction or a downward direction in <FIG>. That is, the guide <NUM> can be moved in the direction to approach and the direction to move away from the conveyance surface 18a of the upstream conveyance belt <NUM>. Accordingly, it is possible to adjust the distance D between the leading end 29a of the guide <NUM> and the conveyance surface 18a.

Subsequently, the operation of the guide <NUM> according to the present embodiment will be described with reference to <FIG> and <FIG>. In <FIG> and <FIG>, the downstream conveyance belt <NUM> is not illustrated.

As illustrated in <FIG>, in a state in which the leading end 29a of the guide <NUM> is arranged so as to approach the conveyance surface 18a of the upstream conveyance belt <NUM>, the rotator <NUM> is held in a state of being in contact with the conveyance surface 18a by a biasing force of the spring <NUM>. When the upstream conveyance belt <NUM> rotates from this state, the rotator <NUM> also rotates accordingly. In this case, since the rotator <NUM> is a circular rotator having a constant distance from a rotation center P to the outer peripheral surface, even when the rotator <NUM> rotates, a distance between the leading end 29a of the guide <NUM> and the conveyance surface 18a of the upstream conveyance belt <NUM> is maintained constant.

Thereafter, as illustrated in <FIG>, when the joint J reaches a position facing the rotator <NUM> along with the rotation of the upstream conveyance belt <NUM>, the rotator <NUM> comes into contact with the portion of the joint J, so that the guide <NUM> swings in a direction of arrow B1 in <FIG>. In other words, when the portion of the joint J comes into contact with the rotator <NUM>, the rotator <NUM> is pushed and moved in a direction away from the conveyance surface 18a, so that the leading end 29a of the guide <NUM> also swings in a direction away from the conveyance surface 18a (direction of arrow B1) in conjunction with displacement of the rotator <NUM>. As a result, a distance between the leading end 29a of the guide <NUM> and an outer peripheral surface of the support roller <NUM> increases, and a distance necessary for the joint J to pass is secured, so that the portion of the joint J can be avoided from coming into contact with the leading end 29a of the guide <NUM>. When the leading end 29a of the guide <NUM> swings in the direction away from the conveyance surface 18a, the distance between the leading end 29a of the guide <NUM> and the portion of the joint J may be larger than or the same as the distance between the leading end 29a of the guide <NUM> and the conveyance surface 18a in the portion other than the joint J. In short, it is sufficient that the guide <NUM> can swing in such a manner that the leading end 29a of the guide <NUM> can avoid the contact with the portion of the joint J.

Thereafter, when the portion of the joint J passes through the position facing the rotator <NUM>, the leading end 29a of the guide <NUM> swings in a direction to approach the conveyance surface 18a (a direction opposite to the arrow B1 direction in <FIG>), and the guide <NUM> and the rotator <NUM> are returned to the original positions (positions illustrated in <FIG>).

As described above, in the present embodiment, the guide <NUM> is displaced (swung) in conjunction with the displacement of the rotator <NUM> due to the contact between the portion of the joint J and the rotator <NUM>, so that the contact of the guide <NUM> with the portion of the joint J can be avoided. As a result, it is not necessary to set the distance between the leading end 29a of the guide <NUM> and the conveyance surface 18a to be large in consideration of interference between the guide <NUM> and the portion of the joint J, so that the distance can be set to be small. Therefore, according to the configuration of the present embodiment, even with the conveyance belt including the joint, the distance between the surface of the conveyance belt and the leading end of the guide can be reduced, and entrance of the sheet between the guide and the conveyance belt can be reduced. As a result, the sheet can be smoothly and reliably guided by the guide.

In the present embodiment, since the guide <NUM> is configured to swing about the support shaft <NUM> to approach and move away from the conveyance surface 18a, displacement of the rear end 29c side of the guide <NUM> can be reduced as compared with a configuration in which the guide <NUM> linearly slides to approach and move away from the conveyance surface 18a. Therefore, in the present embodiment, the guide <NUM> (rear end 29c) can be arranged close to the conveyance surface 19a of the downstream conveyance belt <NUM>, and the sheet can be smoothly and reliably transferred between the guide <NUM> and the downstream conveyance belt <NUM>.

The present disclosure does not exclude a configuration in which the guide linearly slides to approach and move away from the conveyance surface of the conveyance belt. When there is no member arranged close to the rear end of the guide, it is not necessary to consider interference between the member and the rear end of the guide, so that it is also possible to adopt a configuration in which the guide is linearly slid. On the other hand, in the configuration in which the guide <NUM> is arranged between the upstream conveyance belt <NUM> and the downstream conveyance belt <NUM> and it is difficult to secure a space for linearly moving the guide <NUM> as in the present embodiment, it is preferable to adopt the configuration in which the guide is swung.

As illustrated in <FIG>, as seen in an axial direction of the support roller <NUM>, the position of the leading end 29a of the guide <NUM> is preferably set on a straight line L passing through a rotation center Q of the support roller <NUM> (specifically, the support roller <NUM> which the rotator <NUM> faces via the upstream conveyance belt <NUM>) and the rotation center P of the rotator <NUM>. By arranging the leading end 29a of the guide <NUM> at such a position, the leading end 29a of the guide <NUM> can be greatly swung (retracted) in accordance with a timing at which the portion of the joint J reaches the position of the leading end 29a of the guide <NUM>, so that interference between the leading end 29a of the guide <NUM> and the portion of the joint J can be more reliably avoided.

As in the example illustrated in <FIG>, a plurality of rotators 40A and 40B may be arranged side by side in the sheet conveyance direction. In the example illustrated in <FIG>, the two rotators 40A and 40B are arranged at the position of the leading end 29a of the guide <NUM> and a position on the upstream side of the leading end in the sheet conveyance direction. In this case, as illustrated in <FIG>, when the portion of the joint J comes into contact with a first rotator 40A (upstream side), the guide <NUM> swings in the direction away from the conveyance surface 18a in conjunction with the displacement of the rotator 40A due to the contact. Subsequently, as illustrated in <FIG>, the portion of the joint J comes into contact with a second rotator 40B (downstream side), so that the guide <NUM> is held in a state of being swung in the direction away from the conveyance surface 18a. That is, before the portion (protrusion) of the joint J completely passes through the contact position with the first rotator 40A, the portion of the joint J comes into contact with the second rotator 40B, so that the guide <NUM> is held in a swinging state. Therefore, in this case, the guide <NUM> is held in a state of being swung in the direction away from the conveyance surface 18a until the portion of the joint J passes through the second rotator 40B after coming into contact with the first rotator 40A. As a result, the guide <NUM> can be continuously retracted from a stage earlier than the reach of the portion of the joint J, so that the contact between the guide <NUM> and the portion of the joint J can be more reliably avoided. The number of rotators arranged in the sheet conveyance direction is not limited to two, and may be three or more. The rotators may be arranged not only at a position on the upstream side in the sheet conveyance direction with respect to the position of the leading end 29a of the guide <NUM> but also at a position on the downstream side. When a plurality of rotators are mounted, the position of the leading end 29a of the guide <NUM> is preferably set on the straight line L passing the rotation center P of any one of the rotators and the rotation center Q of the support roller <NUM> when viewed from the axial direction of the support roller <NUM>, as in the embodiment of <FIG>. In other words, the rotation center P of any one of the rotators is preferably disposed on the straight line L passing the leading end 29a of the guide <NUM> and the rotation center Q of the support roller <NUM> when viewed from the axial direction of the support roller <NUM>. Thus, the leading end 29a of the guide <NUM> can be greatly swung (retracted) in accordance with a point in time at which the portion of the joint J reaches the position of the leading end 29a of the guide <NUM>, so that interference between the leading end 29a of the guide <NUM> and the portion of the joint J can be more reliably avoided.

In the above-described embodiment, the configuration in which the leading end 29a of the guide <NUM> swings in the direction to approach and the direction to move away from the conveyance surface 18a of the upstream conveyance belt <NUM> is taken as an example, but as in the example illustrated in <FIG>, the leading end 29a of the guide <NUM> may be arranged to approach the conveyance surface 19a of the downstream conveyance belt <NUM>. In this case, when the portion of the joint J of the downstream conveyance belt <NUM> comes into contact with the rotator <NUM>, the leading end 29a of the guide <NUM> swings in the direction away from the conveyance surface 19a as in the above-described embodiment, so that the interference between the leading end 29a of the guide <NUM> and the joint portion can be avoided.

Embodiments of the present disclosure are not limited to the configuration using the conveyance belt in which the joint portion protrudes as described above, and are also applicable to a configuration using a conveyance belt in which the joint portion is recessed in a concave shape as compared with other portions.

In the configuration using the conveyance belt in which the joint portion has the concave shape, the distance between the guide and the conveyance belt increases at the joint portion as opposed to the case where the joint portion has a convex shape, so that there is a possibility that a disadvantage might occur that the sheet enters between the guide and the conveyance belt. However, even in such a configuration, according to an embodiment of the present disclosure, entry of the sheet at the joint portion can be reduced. For example, according to an embodiment of the present disclosure, the guide is displaced in the direction to approach the conveyance surface in accordance with the shape of the joint portion, so that the distance between the guide and the conveyance belt at the joint portion can be reduced, and the entry of the sheet between the guide and the conveyance belt can be reduced.

The present disclosure is also applicable to the following drying device. Hereinafter, a configuration of the drying device according to another embodiment of the present disclosure will be described.

In the drying device <NUM> illustrated in <FIG>, the first heating unit <NUM> includes an infrared irradiator <NUM> in addition to the warm air generator <NUM>. Except for this, the drying device has the same configuration as the drying device according to the above-described embodiment (refer to <FIG>).

In this case, when the sheet S is borne on the transfer cylinder <NUM>, the sheet S is heated by the heat of the warm air generator <NUM> and is heated by the infrared rays emitted from the infrared irradiator <NUM>. As a result, the drying of the ink on the sheet S can be promoted as compared with the drying device according to the above-described embodiment.

Subsequently, in the drying device <NUM> illustrated in <FIG>, a blower fan <NUM> as a cooling device is disposed at a position facing the upstream conveyance belt <NUM>. Air is blown from the blower fan <NUM> to the upstream conveyance belt <NUM> to cool the upstream conveyance belt <NUM>, so that a temperature rise of the upstream conveyance belt <NUM> is reduced. In this case, since the temperature rise of the sheet S conveyed by the upstream conveyance belt <NUM> is also reduced, the occurrence of waviness of the sheet S can also be reduced in addition to density unevenness due to movement of pigment of the ink.

In the drying device <NUM> illustrated in <FIG>, the second heating unit <NUM> includes a heating element <NUM> that heats the downstream conveyance belt <NUM> in addition to a plurality of ultraviolet irradiators <NUM>. The heating element <NUM> is, for example, an infrared heater (IR lamp), and is arranged in the support roller <NUM> on the upstream side that supports the downstream conveyance belt <NUM>. When the heating element <NUM> generates heat, the downstream conveyance belt <NUM> is heated via the support roller <NUM>.

Therefore, when the sheet S is held on the downstream conveyance belt <NUM>, the sheet S is heated by the heat of the heated downstream conveyance belt <NUM>. Furthermore, since the sheet S is irradiated by each ultraviolet irradiator <NUM> with ultraviolet rays, drying of the ink on the sheet S is effectively promoted. Except for the configuration described above, the configuration is the same as that of the drying device illustrated in <FIG>, so that the description thereof is omitted.

In the above-described embodiment, the case where the conveyance device according to the present disclosure is mounted on the inkjet image forming apparatus being an example of a liquid discharge apparatus has been described as an example, but the conveyance device according to the present disclosure is also applicable to other liquid discharge apparatuses.

The "liquid discharge apparatus" means an apparatus that includes a liquid discharger and drives the liquid discharger to discharge liquid onto a sheet. Therefore, the "liquid discharge apparatus" is not limited to one that visualizes a meaningful image such as a character or a figure by the discharged liquid. Examples of the "liquid discharge apparatus" include an apparatus that forms a pattern having no meaning in itself, an apparatus that forms a three-dimensional image, and a treatment liquid discharge apparatus that discharges a treatment liquid onto a surface of a sheet for the purpose of modifying the surface of the sheet.

The "liquid discharge apparatus" to which the conveyance device according to the present disclosure is applied may include devices to feed, convey, and eject the sheet, a pretreatment device, and a post-processing device.

In the "liquid discharge apparatus", the liquid discharger may move relative to the sheet, or the liquid discharger is not necessarily move relative to the sheet. Specific examples of the "liquid discharge apparatus" include a serial type apparatus that moves the liquid discharge head (liquid discharger) or a line type apparatus that does not move the liquid discharge head (liquid discharger).

The above-described "sheet" represents a sheet on which liquid can be at least temporarily adhered, and includes a sheet on which liquid is adhered and fixed, or a sheet to which liquid is adhered to permeate. Specific examples thereof include a recording medium such as paper, recording paper, a recording sheet, a film, and cloth, and an electronic substrate. The "sheet" may be a long sheet (roll paper) wound in a roll shape in addition to a sheet (cut paper) cut into a predetermined size in the sheet conveyance direction in advance.

Examples of the material of the "sheet" include any material on which liquid can be adhered even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramic.

"Liquid" discharged by the "liquid discharge apparatus" is not limited to a particular liquid as long as the liquid has a viscosity or surface tension dischargeable from the liquid discharger. However, preferably, the viscosity of the liquid is not greater than <NUM> mPa·s under ordinary temperature and ordinary pressure or by heating or cooling. More specific examples thereof include solutions, suspensions, and emulsions containing solvents such as water and organic solvents, colorants such as dyes and pigments, function-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as deoxyribonucleic acid (DNA), amino acids, proteins, and calcium, and edible materials such as natural pigments. These can be used for, for example, inkjet ink, surface treatment liquid, electronic element, constituent parts of light emitting element, liquid for forming electronic circuit resist pattern, and material liquid for three-dimensional modeling.

The conveyance device according to an embodiment of the present disclosure is not limited to a device mounted on a liquid discharge apparatus such as an inkjet image forming apparatus. For example, embodiments of the present disclosure are also applicable to a conveyance device mounted on an electrophotographic image forming apparatus that forms an image using toner, or a conveyance device mounted on a belt conveyor that conveys an object other than a sheet.

Claim 1:
A conveyance device (<NUM>), comprising:
a conveyance belt (<NUM>) having a conveyance surface with a joint, the conveyance belt (<NUM>) to convey an object to be conveyed, with the object on the conveyance surface;
characterized by further comprising:
a guide (<NUM>) to approach the conveyance surface and guide the object from or to the conveyance belt (<NUM>); and
a rotator (<NUM>) to contact the conveyance surface (18a),
the guide (<NUM>) to displace in a direction perpendicular to the conveyance surface, in conjunction with displacement of the rotator when the rotator contacts the joint.