Patent Description:
A sheet conveyor has been proposed that is disposed downstream from a drying device provided for an image forming apparatus and includes a cooling member. Such a sheet conveyor serves as an open and close device that conveys a sheet.

Such a sheet conveyor includes a pair of slidably rotatable conveying belts and rotates the conveying belts to convey, from upstream to downstream, a sheet nipped at the nip between the pair of conveying belts. One of the pair of conveying belts turns relative to the other conveying belt so as to be spaced from the other conveying belt, resulting in the achievement of the function of an open and close portion enabling exposure of the inside of the sheet conveyor. Opening between the conveying belts enables the handling of paper jam or the replacement of internal members.

For example, a sheet conveyor has been proposed that is provided with a tension spring to bias an upper conveying belt in the opening direction (see, for example, <CIT>). Typically, such a sheet conveyor is provided with a locking claw that locks the upper conveying belt shut to a lower conveying belt.

In the case where an open and close portion provided for an open and close device is large in weight, an operator needs a large manipulation force for open/shut operation. According to the above configuration of the sheet conveyor in the related art, the upper conveying belt is urged in the opening direction due to the biasing force in the direction of contraction of the tension spring, leading to a reduction in the manipulation force in the opening direction (see, for example, <CIT>). However, as the upper conveying belt turns in the direction of shutting, the stroke of the tension spring increases, and the biasing force in the opening direction increases. Such increases tend to require a large manipulation force to shut the upper conveying belt.

Embodiments of the present disclosure described herein provide an open and close device, a sheet conveyor, and an image forming apparatus. The open and close device includes an open and close portion to open or shut, a biasing mechanism to bias the open and close portion in an opening direction, and a holder to hold the open and close portion shut. The open and close device is characterised by, the biasing mechanism including a first spring whose biasing force is invariable regardless of a stroke of the first spring, and a second spring whose biasing force is variable due to a stroke of the second spring. The sheet conveyor includes the open and close device, and the open and close portion includes a conveyor to convey a sheet. The image forming apparatus includes the sheet conveyor.

According to one aspect of the present disclosure, the open/shut operation of an open and close portion can be easily carried out.

A more complete appreciation of embodiments and the many attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof, which is defined by the appended claims.

It will be further understood that the terms "includes" and/or "including", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In describing example embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the present disclosure is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have the same structure, operate in a similar manner, and achieve a similar result.

Embodiments of the present disclosure are described below with reference to the drawings.

<FIG> is a schematic diagram illustrating a configuration of an image forming apparatus <NUM> that adopts inkjet printing, according to an embodiment of the present disclosure.

Typically, an image forming apparatus <NUM> according to the present embodiment includes a feeder <NUM>, an image former <NUM>, a dryer <NUM>, and an ejector <NUM>. The dryer <NUM> is provided with a sheet conveyor <NUM> as an open and close device. The sheet conveyor <NUM> that serves as an open and close device according to the embodiments of the present disclosure conveys a sheet. As an example of such a sheet, there is a recording medium for recording an image. The sheet conveyor <NUM> according to the present embodiment conveys a sheet P that serves as such a recording medium.

In the image forming apparatus <NUM>, the image former <NUM> forms, with ink as liquid for image forming, an image onto the sheet P fed from the feeder <NUM>. In the image forming apparatus <NUM>, the dryer <NUM> dries the ink on the sheet P and then ejects the sheet P to the ejector <NUM>.

Typically, the feeder <NUM> includes a sheet feeding tray <NUM>, a feeding device <NUM>, and a pair of registration rollers <NUM>. A plurality of sheets P is stacked on the sheet feeding tray <NUM>. The feeding device <NUM> sends out sheets P one by one from the sheet feeding tray <NUM>. The pair of registration rollers <NUM> sends a sheet P into the image former <NUM>. The feeding device <NUM> may be any type of feeding device such as a feeding device including a roller or a rolling member or a feeding device with air suction. After the leading end of the sheet P sent out from the sheet feeding tray <NUM> by the feeding device <NUM> reaches the pair of registration rollers <NUM>, the pair of registration rollers <NUM> operates at a predetermined timing to feed the sheet P to the image former <NUM>. The feeder <NUM> may have any configuration, provided that a sheet P can be sent out to the image former <NUM>.

The image former <NUM> includes a receiving barrel <NUM> and a sheet bearing drum <NUM>. The receiving barrel <NUM> receives the fed sheet P. The sheet bearing drum <NUM> conveys the sheet P conveyed by the receiving barrel <NUM> while bearing the sheet P on its outer circumferential face. The image former <NUM> includes an ink discharger <NUM> and a delivery barrel <NUM>. The ink discharger <NUM> discharges ink to the sheet P borne on the sheet bearing drum <NUM>. The delivery barrel <NUM> delivers, to the dryer <NUM>, the sheet P conveyed by the sheet bearing drum <NUM>. The leading end of the sheet P conveyed from the feeder <NUM> to the image former <NUM> is gripped by a sheet gripper arranged on the surface of the receiving barrel <NUM>. Then, the sheet P is conveyed along with the movement of the surface of the receiving barrel <NUM>. The sheet P conveyed by the receiving barrel <NUM> is delivered to the sheet bearing drum <NUM> at a position at which the sheet P faces the sheet bearing drum <NUM>.

The sheet bearing drum <NUM> has a surface provided with a sheet gripper. The leading end of the sheet P is gripped by the sheet gripper. The sheet bearing drum <NUM> has a plurality of suction holes dispersed on its surface. A suction device <NUM> generates, to each suction hole, an air flow of suction to the inside of the sheet bearing drum <NUM>. The sheet P delivered from the receiving barrel <NUM> to the sheet bearing drum <NUM> is sucked on the surface of the sheet bearing drum <NUM> due to air flows of suction, with its leading end gripped by the sheet gripper. Then, the sheet P is conveyed along with the movement of the surface of the sheet bearing drum <NUM>.

The ink discharger <NUM> includes liquid discharge heads 220C, <NUM>, 220Y, and <NUM> for inks in four colors of cyan (C), magenta (M), yellow (Y), and black (K), in order to discharge the four color inks to form an image. The liquid discharge heads 220C, <NUM>, 220Y, and <NUM> may each have any configuration, provided that liquid can be discharged. For example, where appropriate, a liquid discharge head that discharges a special ink such as white ink, gold ink, or silver ink may be arranged, or a liquid discharge head that discharges liquid not for forming an image such as surface coating liquid may be arranged.

Due to drive signals based on image information, the liquid discharge heads 220C, <NUM>, 220Y, and <NUM> of the ink discharger <NUM> are controlled in the discharging operation. At the time of passage of the sheet P borne on the sheet bearing drum <NUM> through the region in which the sheet P faces the ink discharger <NUM>, the liquid discharge heads 220C, <NUM>, 220Y, and <NUM> discharge the respective color inks to form an image corresponding to the image information. The image former <NUM> may have any configuration, provided that the image former <NUM> causes liquid to adhere to a sheet P to form an image.

The dryer <NUM> includes a drying mechanism <NUM> and a conveying mechanism <NUM>. The drying mechanism <NUM> dries the ink adhering on the sheet P due to the image former <NUM>. The conveying mechanism <NUM> conveys the sheet P conveyed from the image former <NUM>. The sheet P conveyed from the image former <NUM> is received by the conveying mechanism <NUM> and then is conveyed while passing the drying mechanism <NUM>, followed by delivery to the sheet conveyor <NUM>. While the sheet P is passing the drying mechanism <NUM>, the ink on the sheet P is subjected to drying. Thus, a liquid component such as moisture, in the ink evaporates, so that the ink fastens on the sheet P and additionally the sheet P is prevented from curling.

The sheet conveyor <NUM> includes an upper conveyance module <NUM> and a lower conveyance module <NUM> that convey a sheet P. The sheet conveyor <NUM> according to the present embodiment serves as a cooling device that cools the sheet P having passed the drying mechanism <NUM>. The sheet conveyor <NUM> cools the sheet P being conveyed and delivers the cooled sheet P to the ejector <NUM> on the downstream side.

The upper conveyance module <NUM> and the lower conveyance module <NUM> are provided with a cooler <NUM> inside. The cooler <NUM> includes a plurality of cooling members <NUM>. Each cooling member <NUM> abuts on the inner face of an upper conveying belt <NUM> or a lower conveying belt <NUM>. Each cooling member <NUM> is coupled to the cooling device through a channel pipe and a tube. Due to a flow of cooling liquid as a coolant from the cooling device to each cooling member <NUM> through the channel pipe, the sheet P being conveyed by the upper conveying belt <NUM> and the lower conveying belt <NUM> is cooled.

The ejector <NUM> includes a sheet ejection tray <NUM> on which a plurality of sheets P can be stacked. The sheet P conveyed from the dryer <NUM> is stacked and retained in order on the sheet ejection tray <NUM>. The ejector <NUM> may have any configuration, provided that a sheet P can be ejected.

The image forming apparatus <NUM> according to the present embodiment that serves as an open and close device is provided with the sheet conveyor <NUM> that conveys a sheet. The sheet conveyor <NUM> is described below in detail with reference to <FIG>, <FIG>, <FIG>, and <FIG>.

<FIG> is a perspective view of the sheet conveyor <NUM> according to the present embodiment.

As illustrated in <FIG>, the sheet conveyor <NUM> includes the upper conveyance module <NUM> as an open and close portion, the lower conveyance module <NUM>, and a hoisting mechanism <NUM> as a biasing mechanism. The open and close portion according to the embodiments of the present disclosure serves as a conveyor that conveys a sheet. The open and close device according to the embodiments of the present disclosure is not limited to a sheet conveyor, and can be applied to any open and close device provided with an open and close portion.

The upper conveying belt <NUM> is stretched around a plurality of rollers <NUM> to <NUM>. The lower conveying belt <NUM> is stretched around a plurality of rollers <NUM> to <NUM>. The upper conveying belt <NUM> and the lower conveying belt <NUM> run circumferentially, so that the sheet P is conveyed in the direction of an arrow A while being nipped at the nip between the upper conveying belt <NUM> and the lower conveying belt <NUM>.

<FIG> is a side view of the sheet conveyor <NUM> of <FIG> with the upper conveyance module <NUM> shut, according to the present embodiment.

Each one of the multiple rollers <NUM> to <NUM> that stretch the upper conveying belt <NUM> has an end in the axial direction, and that end is supported by an upper front plate <NUM>. As illustrated in <FIG>, the other end of each one of the multiple rollers <NUM> to <NUM> is supported by an upper rear plate <NUM>. Each one of the multiple rollers <NUM> to <NUM> that stretch the upper conveying belt <NUM> has an end in the axial direction, and that end is supported by a lower front plate <NUM>. As illustrated in <FIG>, the other end of each one of the multiple rollers <NUM> to <NUM> is supported by a lower rear plate <NUM>. The upper conveyance module <NUM> includes, for example, the upper conveying belt <NUM>, the multiple rollers <NUM> to <NUM>, the upper front plate <NUM>, the upper rear plate <NUM>, and the cooling member <NUM> inside the upper conveying belt <NUM>. The lower conveyance module <NUM> includes, for example, the lower conveying belt <NUM>, the rollers <NUM> to <NUM>, the lower front plate <NUM>, the lower rear plate <NUM>, and the cooling member <NUM> inside the lower conveying belt <NUM>.

As illustrated in <FIG>, the upper front plate <NUM> is provided with a handle <NUM> and a pair of locking portions <NUM>. The handle <NUM> is provided at the center in the width direction of the upper front plate <NUM>. The hoisting mechanism <NUM> urges, through a wire <NUM> coupled to the upper front plate <NUM>, the upper conveyance module <NUM> upward against gravity.

As illustrated in <FIG>, each one of the pair of locking portions <NUM> is arranged around a rotation shaft 32a in a rotatable manner. The rotation shaft 32a has its axial direction identical to the direction perpendicular to the drawing plane of <FIG>. Each one of the pair of locking portions <NUM> has a locking hole 32b. The lower front plate <NUM> is provided with locking projections 29a. The pair of locking portions <NUM> provided for the upper front plate <NUM> are pressurized upward in <FIG> by the hoisting mechanism <NUM>. Accordingly, with the locking projections 29a disposed one-to-one in the locking holes 32b, the locking portions <NUM> abut on the respective locking projections 29a since the locking portions <NUM> are urged upward, so that the locking portions <NUM> lock due to the locking projections 29a. Thus, the upper conveyance module <NUM> is locked to the lower conveyance module <NUM>, so that the state in <FIG> is retained as the state where the upper conveyance module <NUM> is shut. The pair of locking portions <NUM> and the locking projections 29a serve as a holder that holds the open and close portion shut.

The lower rear plate <NUM> is provided with a rotation center <NUM>. The upper rear plate <NUM> is coupled to the rotation center <NUM>, and the upper conveyance module <NUM> turns around the rotation center <NUM>.

<FIG> is a side view of the sheet conveyor <NUM> of <FIG> with the upper conveyance module <NUM> unlocked, according to the present embodiment.

In order to open the upper conveyance module <NUM>, the handle <NUM> is turned upward while being gripped, so that the locking portions <NUM> turn around the rotation shaft 32a as in <FIG>. Due to such a configuration, the locking projections 29a are separated from the locking holes 32b, so that the upper conveyance module <NUM> is unlocked to the lower conveyance module <NUM>. The pair of locking portions <NUM> and the locking projections 29a serve as a latch mechanism that keeps the upper conveyance module <NUM> locked until unlocking due to a manipulation of the handle <NUM>.

<FIG> is a side view of the sheet conveyor <NUM> of <FIG> with the upper conveyance module <NUM> open, according to the present embodiment.

As illustrated in <FIG>, the upper conveyance module <NUM> turns in the opening direction around the rotation center <NUM> due to the biasing force T of the hoisting mechanism <NUM>. The biasing force T of the hoisting mechanism <NUM> is larger than the self-weight W of the upper conveyance module <NUM>. Thus, unlocking the upper conveyance module <NUM> to the lower conveyance module <NUM> causes the upper conveyance module <NUM> to turn automatically in the opening direction. Thus, the face for sheet conveyance between the upper conveying belt <NUM> and the lower conveying belt <NUM> is exposed outward, so that paper jam can be handled. In addition, members inside the sheet conveyor <NUM> can be replaced.

<FIG> is a perspective view of the hoisting mechanism <NUM>, according to the present embodiment.

The configuration or structure of the hoisting mechanism <NUM> is described below in detail with reference to <FIG>.

The hoisting mechanism <NUM> includes, for example, a first spring <NUM>, a second spring <NUM>, a sub-plate <NUM>, a slider <NUM>, and a wire <NUM> as a linear member. The first spring <NUM> serves as a constant load spring that is constant in biasing force (load) regardless of stroke. In the present embodiment, a conston spring is used for the first spring <NUM>. The second spring <NUM> serves as a spring that is variable in load due to stroke. A coil spring is used for the second spring <NUM>. In the present embodiment, such second springs <NUM> are arranged on both sides of the first spring <NUM>. The first spring <NUM> has an end to which the sub-plate <NUM> is attached. The sub-plate <NUM> is coupled to the slider <NUM> tabular in shape. Each second spring <NUM> has an end attached to the slider <NUM> and the other end secured to a housing <NUM> of the sheet conveyor <NUM>. The wire <NUM> has an end coupled to the upper front plate <NUM> and the other end coupled to the slider <NUM>.

The first spring <NUM> has both sides supported by the housing <NUM>. The first spring <NUM> is arranged so as to be rotatable around a rotation center 51a relative to the housing <NUM>. The first spring <NUM> rotates to wind up or off its spring portion. As described above, the first spring <NUM> according to the present embodiment is a winding spring such as a conston spring.

In the present embodiment, against the weight W of the upper conveyance module <NUM> illustrated in <FIG>, the hoisting mechanism <NUM> applies the biasing force T exceeding the weight W to bias the upper conveyance module <NUM> in the opening direction. The biasing force T is the sum of the biasing force of the first spring <NUM> as a constant load spring and the biasing force of the second springs <NUM> variable in load due to stroke.

As the upper conveyance module <NUM> moves in the opening direction, the stroke of each second spring <NUM> decreases, so that the biasing force in the opening direction due to the second springs <NUM> decreases. Accordingly, as the upper conveyance module <NUM> opens, the rate of opening decreases. Then, with the biasing force T and the weight W in balance, the movement of the upper conveyance module <NUM> in the opening direction stops.

In order to shut the upper conveyance module <NUM>, the operator turns the upper conveyance module <NUM> against the biasing force T until the state in <FIG> is obtained, and then hooks the locking portions <NUM> together with the locking projections 29a.

Due to such a configuration, the upper conveyance module <NUM> can be shut again. In both the state where the upper conveyance module <NUM> is shut in <FIG> and the state where the upper conveyance module <NUM> is open in <FIG>, the first spring <NUM> has the spring portion partially reeled out. Thus, the first spring <NUM> keeps biasing force applied to the upper conveyance module <NUM>.

As described above, according to the present embodiment, with a configuration in which the biasing force T is larger than the weight W of the upper conveyance module <NUM>, unlocking between the pair of locking portions <NUM> and the locking projections 29a enables the upper conveyance module <NUM> to move automatically in the opening direction. Accordingly, a series of operations to open the upper conveyance module <NUM> can be easily carried out. In particular, in the present embodiment, since the upper conveyance module <NUM> is provided with the cooling member <NUM> inside and the image forming apparatus <NUM> including the sheet conveyor <NUM> is a large printing machine, the upper conveyance module <NUM> is large in weight. However, the upper conveyance module <NUM> large in weight can be easily opened. The state where the upper conveyance module <NUM> is open can be retained without the application of external force, leading to the facilitation of working, such as handling of paper jam.

Furthermore, with a configuration in which biasing force is applied to the upper conveyance module <NUM> by the second springs <NUM> variable in load due to stroke, the rate in the opening direction of the upper conveyance module <NUM> can reduce, leading to a stop. Due to such a configuration, the rate of opening of the upper conveyance module <NUM> can be controlled, and the upper conveyance module <NUM> can be stopped at a predetermined position in the opening direction without any restricting members.

Since the first spring <NUM> as a constant load spring is provided, the manipulation force to shut the upper conveyance module <NUM> is small. In other words, the stroke and biasing force of the second springs <NUM> are in proportion. Thus, for example, in order to move the upper conveyance module <NUM> with only the second springs <NUM> for the state of opening in <FIG>, a large biasing force is required, leading to an increase in the spring constant of each second spring <NUM>. However, in this case, if the second springs <NUM> have a stoke quantity such that the upper conveyance module <NUM> transitions from the state in <FIG> to the state in <FIG>, the biasing force T in the state of opening in <FIG> is excessively larger than the weight W since the spring constant of each second spring <NUM> is large. In other words, the manipulation force to manipulate the upper conveyance module <NUM> into the state of opening is large. In the present embodiment, as the first spring <NUM>, which isa constant load spring, and the second springs <NUM> are used in combination, each one of the second springs <NUM> has a small spring constant. Thus, even when the stroke of the second springs <NUM> lengthens, the biasing force of the second springs <NUM> is kept small, so that the manipulation force to shut the upper conveyance module <NUM> is small.

As described above, in the present embodiment, the first spring <NUM>, which is a constant load spring, and the second springs <NUM> whose load is variable depending on the stroke bias the upper conveyance module <NUM> in the opening direction. Thus, the open/shut operation of the upper conveyance module <NUM> can be easily carried out.

In the present embodiment, as illustrated in <FIG>, the upper conveyance module <NUM> is positioned to the lower conveyance module <NUM> with a state where the lower wall face of the locking hole 32b of each one of the pair of locking portions <NUM> abuts on the corresponding locking projection 29a. Thus, the upper conveying belt <NUM> and the lower conveying belt <NUM> are disposed in a proper positional relationship, so that a conveyance nip is formed between the upper conveying belt <NUM> and the lower conveying belt <NUM> in the proper positional relationship.

As illustrated in <FIG>, the wire <NUM> partially abuts on a pulley <NUM> that serves as an abutment part. Since the wire <NUM> abuts on the pulley <NUM>, before and behind the pulley <NUM>, a change is made in the direction in which the wire <NUM> extends. Due to the pulley <NUM>, the direction in which the hoisting mechanism <NUM> applies biasing force to the wire <NUM> can be changed, and the degree of freedom with which the hoisting mechanism <NUM> is designed, such as the arrangement of the hoisting mechanism <NUM>, increases. Thus, the hoisting mechanism <NUM> can be disposed at a position to which the operator gains no access, so that, for example, the first spring <NUM> can be prevented from being touched by the operator. In the sheet conveyor <NUM> according to the present embodiment, because no member is allowed to be disposed in the region through which a sheet passes, hoisting with the wire <NUM> from above is favorable.

Due to the pulley <NUM> that rotates as an abutment part, the open/shut operation of the upper conveyance module <NUM> can be smoothly carried out with a low frictional force between the wire <NUM> and the pulley <NUM>. For example, a roller that does not rotate may be used as an abutment part.

<FIG> is a side view of a pair of guides <NUM> provided for the hoisting mechanism <NUM>, according to an embodiment of the present disclosure.

In the present embodiment, a guide is arranged that guides the slider <NUM> in the stroke direction of the first spring <NUM> or the second springs <NUM> to prevent the first spring <NUM> from twisting. Specifically, as illustrated in <FIG>, the slider <NUM> has an upper face abutting on a guide <NUM> through a rolling bearing <NUM> and a lower face abutting on the pair of guide <NUM> through a rolling bearing <NUM>. Thus, at the time of changes in the stroke quantities of the first spring <NUM> and the second springs <NUM>, the slider <NUM> can be guided along the surfaces of the pair of guides <NUM>, so that the first spring <NUM> can be restricted from twisting. In particular, since the slider <NUM> abuts on the rolling bearings <NUM>, the manipulation force for open/shut operation of the upper conveyance module <NUM> can be reduced with a low sliding resistance between the slider <NUM> and the guide <NUM>. The stroke direction of the first spring <NUM> or the second springs <NUM> in which the slider <NUM> is guided corresponds to the left-right direction of <FIG>.

<FIG> is a perspective view of the multiple bearings <NUM> provided for the slider <NUM>, according to an embodiment of the present disclosure.

As illustrated in <FIG>, rolling bearings <NUM> abut on the slider <NUM> at four places: two places on the left and right sides at the front of the slider <NUM> and two places on the left and right sides at the rear of the slider <NUM>. Such a configuration stabilizes the direction in which the slider <NUM> moves.

<FIG> is a side view of a pair of guides <NUM> according to an alternative embodiment of the present disclosure.

The pair of guides <NUM> that guide the slider <NUM> is not limited to a configuration or structure with the bearings <NUM> described above. For example, as illustrated in <FIG>, the pair of guides <NUM> may be arranged that slide above and blow the slider <NUM> to restrict the direction in which the slider <NUM> moves. In the present embodiment, the pair of guides <NUM> are formed of sheet metal. Such a configuration in which bearings are arranged as a guide as described above is preferable because of a low sliding resistance between the slider <NUM> and the guide. A guide may be achieved with the housing of a sheet conveyor. A type of bearing different from such a rolling bearing <NUM> may be adopted as a bearing.

As illustrated in <FIG>, the rotation center 51a of the first spring <NUM> is arranged on the same side as a winding portion 51b of the first spring <NUM> with respect to an extended plane B obtained by extending a coupling face 54a on which the wire <NUM> is coupled to the slider <NUM>. Thus, even when the stroke shortens due to the winding-up of the first spring <NUM>, the winding portion 51b of the first spring <NUM> can be prevented from expanding upward in <FIG>. Due to such a configuration, the winding portion 51b can be wound up smoothly, and the region that is occupied by the first spring <NUM> can be reduced. The winding portion 51b corresponds to a portion that is part of the spring portion of the first spring <NUM> and is disposed between a drum 51c for winding up the spring portion and the sub-plate <NUM> with the slider <NUM>. In other words, on the drawing plane of <FIG> that is a plane perpendicular to the virtual axial direction of the rotation center 51a of the first spring <NUM> (the direction perpendicular to the drawing plane of <FIG>), with respect to an extended line B resulting from extension of a portion 55a that the wire <NUM> has between the slider <NUM> and the pulley <NUM>, the rotation center 51a of the first spring <NUM> is arranged on the side on which the first spring <NUM> has the winding portion 51b. Thus, the winding portion 51b can be prevented from expanding upward in <FIG>.

<FIG> is a side view of the hoisting mechanism <NUM> according to an alternative embodiment of the present disclosure.

In the above embodiment of the present disclosure, a conston spring is used as the first spring that is a constant load spring. However, no limitation on the embodiments of the present disclosure is intended thereby. For example, a hoisting mechanism <NUM> according to the present embodiment described with reference to <FIG> includes a gas spring as a first spring <NUM>. In a similar manner to the above embodiment of the present disclosure, the biasing force in the direction of contraction of the first spring <NUM> is applied to an open and close portion through a wire <NUM>. In a similar manner to the case where a conston spring is used as the first spring, with the configuration of the hoisting mechanism <NUM> according to the present embodiment, the open/shut operation of the open and close portion can be easily carried out. Depending on the configuration of an open and close device, the use of a gas spring as the first spring enables a reduction in cost. The use of a conston spring as the first spring enables a long stroke.

<FIG> is a side view of an open and close device according to an alternative embodiment of the present disclosure.

In the open and close device according to the above embodiment of the present disclosure, the upper conveyance module <NUM>, which is the open and close portion, turns around the rotation center <NUM> to open or shut. However, no limitation on the embodiments of the present disclosure is intended thereby. For example, an open and close device <NUM> illustrated in <FIG> includes an open and close portion <NUM> that slides in the up-down direction, a fixed unit <NUM>, a holder that holds the open and close portion <NUM> at the position, at which the open and close portion <NUM> is shut, indicated with a solid line in <FIG>, and a hoisting mechanism <NUM> as a biasing mechanism. With biasing force T larger than the weight W of the open and close portion <NUM>, the hoisting mechanism <NUM> urges the open and close portion <NUM>. Due to the biasing force T, the open and close portion <NUM> opens to the position indicated with a dotted line in <FIG>. The operator manipulates the open and close portion <NUM> to the position indicated with the solid line in <FIG> such that the open and close portion <NUM> is held by the holder, so that the open and close portion <NUM> is shut. In a similar manner to the above embodiment of the present disclosure, the open/shut operation of the open and close portion <NUM> according to the present embodiment can be easily carried out.

Although the image forming apparatus <NUM> according to the above embodiments of the present disclosure includes the feeder <NUM>, the image former <NUM>, the dryer <NUM>, and the ejector <NUM>, other functions may be appropriately added to the image forming apparatus <NUM>. For example, a pre-processing unit that performs pre-processing for image forming can be added between the feeder <NUM> and the image former <NUM> or a post-processing unit that performs post-processing for image forming can be added between the dryer <NUM> and the ejector <NUM>.

An exemplary pre-processing unit performs treatment-liquid coating to coat, onto a sheet P, treatment liquid that reacts with ink to prevent blurring. The pre-processing to be performed by the pre-processing unit is not limited to any particular processing. An exemplary post-processing unit performs sheet reversing and conveying to reverse the sheet on which an image is formed by the image former <NUM> and convey the reversed sheet to the image former <NUM> again for double-sided image forming to the sheet. Another exemplary post-processing unit performs processing to bind a plurality of sheets each having an image formed. The post-processing units may be, for example, a correction mechanism that corrects sheet deformation and a cooling mechanism that cools a sheet. The post-processing to be performed by the post-processing unit is not limited to any particular processing.

In the present embodiment, an exemplary inkjet image forming apparatus is described. The image forming apparatus is not limited to an apparatus including a liquid discharge head that discharges liquid to the dried face of a recording medium to visualize a meaningful image such as a character or a figure. Examples of the "image forming apparatus" include an apparatus that forms a meaningless pattern. The material of such a recording medium is not limited and may be any material to which liquid can adhere even temporarily such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramic. The material may be any of the materials used for film products, cloth products such as clothes, construction materials, such as wallpaper and flooring, and leather products. The image forming apparatus may include, for example, means for feeding, conveying, and ejecting a medium to which liquid can adhere, a pre-processing device, and a post-processing device.

The term "liquid" may have any viscosity or surface tension as long as the liquid can be discharged from a head, and is not limited to any particular liquid. Preferably, such liquid to be discharged has a viscosity equal to or lower than <NUM> mPa·s at normal temperature and under normal atmospheric pressure or due to heating or cooling. More specific examples of the liquid include a solution, a suspension, and an emulsion that contain a solvent, such as water or an organic solvent, a colorant, such as dye or pigment, a functional material, such as a polymerizable compound, resin, or a surfactant, a biocompatible material, such as deoxyribonucleic acid (DNA), an amino acid, protein, or calcium, or an edible material such as a natural pigment. Such a solution, a suspension, and an emulsion can be used, for example, for inkjet inks and surface treatment liquids.

The image forming apparatus may be, but is not limited to, an apparatus in which a liquid discharge head and a recording medium move relatively. Concrete examples of such an apparatus include, for example, a serial head apparatus that moves a liquid discharge head and a line head apparatus that does not move a liquid discharge head.

The liquid discharge head is a functional component that discharges/j ets liquid through a discharge hole (nozzle). As a source that generates energy to discharge liquid, used can be means for generating energy for discharge, such as a piezoelectric actuator (laminated piezoelectric element or thin-film piezoelectric element), a thermal actuator including an electrothermal conversion element such as a heating resistive element, and an electrostatic actuator including a diaphragm and opposed electrodes. The means to be used for generating energy for discharge is not limited.

Furthermore, the open and close device embodiments of the present disclosure may be applied to the configuration or structure of, for example, a sheet conveyor provided for an electrophotographic image forming apparatus.

Note that numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the embodiments of the present disclosure may be practiced otherwise than as specifically described herein. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the appended claims.

Claim 1:
An open and close device (<NUM>, <NUM>) comprising:
an open and close portion (<NUM>, <NUM>, <NUM>) to open or shut;
a biasing mechanism (<NUM>) to bias the open and close portion (<NUM>, <NUM>, <NUM>) in an opening direction; and
a holder (29a, <NUM>) to hold the open and close portion (<NUM>, <NUM>, <NUM>) shut,
the open and close device (<NUM>, <NUM>) being characterised by the biasing mechanism (<NUM>) including a first spring (<NUM>, <NUM>) whose biasing force is invariable regardless of a stroke of the first spring (<NUM>, <NUM>), and a second spring (<NUM>) whose biasing force is variable due to a stroke of the second spring (<NUM>).