Patent Description:
In recent years, there are cases where an image is printed on any of media having various thicknesses and shapes such as metal, glass, and tile.

<CIT> discloses a printer that forms an image on a disc while transporting the disc placed on a transport table together with the transport table.

<CIT> discloses an additive manufacturing system for printing a three-dimensional part using electrophotography. The additive manufacturing system includes a rotatable photoconductor component, first and second development stations configured to develop layers of materials on a surface of the rotatable photoconductor component while the rotatable photoconductor component rotates in opposing rotational directions, and a platen configured to operably receive the developed layers in a layer-by-layer manner to print the three-dimensional part from at least a portion of the received layers.

In a case where an image is formed on any of media having various thicknesses and shapes by a method of transferring an image by bringing a transfer unit into contact with a medium, print quality may undesirably decrease, for example, due to misregistration of the medium that occurs due to a shock caused by the contact of the transfer unit with the medium.

Accordingly, it is an object of the present invention to provide an image forming apparatus adopting a technique of keeping a decrease in print quality small in a case where an image is printed on any of media having various thicknesses and shapes, as compared with a configuration in which a medium directly placed on a transport unit such as a transport belt is transported.

The present invention is provided by the appended claims. The following disclosure serves a better understanding of the present invention.

According to the present invention, there is provided an image forming apparatus including a transfer unit that transfers an image onto an object by making contact with the object; an attachment table to which the object is attached and that changes a height thereof in accordance with force by which the transfer unit makes contact with the object; and a transport unit that transports the attachment table to which the object has been attached along a transport path.

The image forming apparatus is configured such that the attachment table fixes the object at least in a transport direction in which the object is transported by the transport unit.

The image forming apparatus is configured to further include a jig that fastens at least a portion of the object other than a surface on which an image is to be transferred, wherein the attachment table includes a fastener that positions and fixes the jig.

The image forming apparatus is configured such that the jig fastens the object at least from a front side in the transport direction in which the object is transported by the transport unit; and the transfer unit starts transfer of an image by making contact with the object after making contact with the jig before the start of the transfer of the image.

The image forming apparatus is configured such that a portion of the jig located on the front side in the transport direction is inclined downward toward the front side in the transport direction.

The image forming apparatus is configured such that the attachment table changes the height thereof while being inclined in accordance with force applied when the transfer unit makes contact with the object.

The image forming apparatus is configured such that the attachment table includes a mobile part that is moved along the transport path by the transport unit and a table part on which the object is placed; and the table part is supported on the mobile part by elastic bodies independently at a plurality of positions.

The image forming apparatus is configured such that the attachment table includes a mobile part that is moved along the transport path by the transport unit, a table part on which the object is placed, and a plate-shaped elastic member sandwiched between the table part and the mobile part.

A decrease in print quality that occurs when the object is shifted due to a shock can be kept small as compared with a configuration in which a medium placed on a transport unit is transported.

According to the present invention, misregistration of the object that occurs due to contact with the transfer unit when the object is transported can be kept small as compared with the configuration in which a medium placed on a transport unit is transported.

According to the present invention, objects having various shapes and sizes can be easily attached to the attachment table by using jigs according to the objects as compared with a configuration in which the object is attached to the attachment table without a jig.

According to the present invention, a shock caused when the transfer unit makes contact with the object can be lessened as compared with a configuration in which the transfer unit makes contact with the object without making contact with the jig.

According to the present invention, a shock caused when the transfer unit makes contact with the jig can be lessened as compared with a configuration in which the jig does not have an inclined portion.

According to the present invention, a shock caused when the object and the transfer unit make contact with each other as compared with a case where the attachment table is not inclined.

According to the present invention, the table part is independently supported by elastic bodies at plural positions. With this configuration, the elastic bodies individually sink down. This allows the table part to move up and down while being inclined.

According to the present invention, the plate-shaped elastic body is sandwiched. This allows the table part to move up and down while being inclined depending on a position of contact between the object and the transfer unit.

An exemplary embodiment of the present disclosure is described in detail below with reference to the attached drawings. An image forming apparatus according to the present exemplary embodiment is an image forming apparatus employing digital printing. Although an electrophotographic system, an inkjet system, and the like are known as digital printing systems, the electrophotographic system is assumed in the present exemplary embodiment. In the electrophotographic system, a transfer unit and a medium are brought into contact with each other when an image is transferred onto the medium. Furthermore, in the present exemplary embodiment, any of media having various thicknesses and shapes such as metal, glass, and tile is assumed as an object on which an image is to be printed. Apparatus Configuration.

<FIG> illustrates a configuration of an image forming apparatus to which the present exemplary embodiment is applied. The image forming apparatus <NUM> includes a transfer unit <NUM>, a fixing unit <NUM>, a medium attaching detaching unit <NUM>, and a transport mechanism <NUM>. Furthermore, the image forming apparatus <NUM> includes a controller (not illustrated) having one or more processors, which are computing units, a memory serving as a working region in data processing, and a storage device that holds a program and data. The controller may be a single controller that controls operation of the whole image forming apparatus <NUM> or may be controllers individually provided in units such as the transfer unit <NUM>, the fixing unit <NUM>, and the transport mechanism <NUM>.

The transfer unit <NUM> is a unit that transfers an image formed with particles such as toner onto a medium <NUM>. The fixing unit <NUM> is a unit that fixes, on a surface of the medium <NUM>, an image transferred by the transfer unit <NUM> by heating the medium <NUM>. The medium attaching detaching unit <NUM> is a unit in which a user of the image forming apparatus <NUM> attaches the medium <NUM> to an attachment table (described later) provided in the transport mechanism <NUM>. The transport mechanism <NUM> is provided across the transfer unit <NUM>, the fixing unit <NUM>, and the medium attaching detaching unit <NUM>, and transports the medium <NUM> on which an image is to be printed to the units <NUM>, <NUM>, and <NUM> as indicated by the arrow in <FIG>.

The medium attaching detaching unit <NUM> is a housing having an opening through which the medium <NUM> can be carried into and out of the medium attaching detaching unit <NUM>. In the medium attaching detaching unit <NUM>, one end portion of a transport rail <NUM> that constitutes the transport mechanism <NUM> is located, and a transport start position and a transport end position are set. This will be described in detail later. In the present exemplary embodiment, the transport start position and the transport end position are set at the same position. In an initial state, an attachment table <NUM> that constitutes the transport mechanism <NUM> is disposed at the position of the transport rail <NUM> set as the transport start position and the transport end position. The user attaches a jig <NUM> holding the medium <NUM> to the attachment table <NUM> by putting the jig <NUM> into the housing of the medium attaching detaching unit <NUM> through the opening, thereby making the medium <NUM> transportable by the transport mechanism <NUM>. After an image is transferred onto the medium <NUM> by the transfer unit <NUM> and fixed by the fixing unit <NUM>, the attachment table <NUM> on which the medium <NUM> is placed moves along the transport rail <NUM> and reaches the transport end position. In this state, the user detaches the jig <NUM> holding the medium <NUM> from the attachment table <NUM> and takes the jig <NUM> out through the opening of the housing of the medium attaching detaching unit <NUM>.

<FIG> illustrates a configuration of the transfer unit <NUM>. The transfer unit <NUM> forms an image with charged particles and transfers the image onto the medium <NUM> by generating an electric field. The transfer unit <NUM> includes a developing device <NUM>, a first transfer roll <NUM>, and an intermediate transfer belt <NUM>. The intermediate transfer belt <NUM> is tensioned between the developing device <NUM> and a position where an image is transferred onto the medium <NUM> by rollers <NUM> and <NUM> and a backup roll <NUM>. Furthermore, the transfer unit <NUM> includes a cleaning device <NUM> for removing particles attached to the intermediate transfer belt <NUM>.

The developing device <NUM> is a unit that forms, on a photoreceptor, an electrostatic latent image of an image to be transferred and develops the image by attaching charged particles to the electrostatic latent image on the photoreceptor. As the developing device <NUM>, an existing device used in an electrophotographic image forming apparatus can be used. <FIG> illustrates an example of a configuration employed in a case where color image formation processing is performed by using four colors, that is, three colors: yellow, magenta, and cyan, and an additional one color: black. The developing device <NUM> is provided for each of these colors, and the developing devices <NUM> for yellow, magenta, cyan, and black are given suffixes Y, M, C, and K indicative of the colors in <FIG>. In the following description, the suffixes are omitted in a case where the colors of the developing devices <NUM> need not be distinguished although the suffixes Y, M, C, and K are given to the reference signs in a case where the colors are distinguished.

The first transfer roll <NUM> is a unit used to transfer (first transfer) an image formed by the developing device <NUM> onto the intermediate transfer belt <NUM>. The first transfer roll <NUM> is disposed so as to face the photoreceptor of the developing device <NUM>, and the intermediate transfer belt <NUM> is located between the developing device <NUM> and the first transfer roll <NUM>. The first transfer roll <NUM> is provided corresponding to each of the developing devices 110Y, <NUM>, 110C, and <NUM>. In <FIG>, the first transfer rolls <NUM> corresponding to the developing devices 110Y, <NUM>, 110C, and <NUM> of the respective colors are given suffixes Y, M, C, and K indicative of the colors. In the following description, the suffixes are omitted in a case where the colors of the first transfer rolls <NUM> need not be distinguished although the suffixes Y, M, C, and K are given to the reference signs in a case where the colors are distinguished.

The intermediate transfer belt <NUM>, the rollers <NUM> and <NUM>, and the backup roll <NUM> are units used to transfer an image formed by the developing device <NUM> onto the medium <NUM>. As illustrated in <FIG>, the intermediate transfer belt <NUM> rotates in a direction indicated by the arrows in <FIG> (a counterclockwise direction in the example illustrated in <FIG>) while being suspended around the rollers <NUM> and <NUM> and the backup roll <NUM> in a tensioned state. For example, one or both of the rollers <NUM> and <NUM> is(are) a roller(s) that is(are) driven to rotate, and the intermediate transfer belt <NUM> is pulled by rotation of this(these) roller(s). In this way, the intermediate transfer belt <NUM> rotates.

An outer surface of the intermediate transfer belt <NUM> in the example of the configuration in <FIG> is a surface (hereinafter referred to as a "transfer surface") on which an image is held. An image is transferred from the photoreceptor of the developing device <NUM> onto the transfer surface of the intermediate transfer belt <NUM> when the intermediate transfer belt <NUM> passes between the developing device <NUM> and the first transfer roll <NUM>. In the example of the configuration illustrated in <FIG>, images of the respective colors: yellow (Y), magenta (M), cyan (C), and black (K) are superimposed on the transfer surface by the developing devices 110Y, <NUM>, 110C, and <NUM> and the first transfer rolls 120Y, <NUM>, 120C, and <NUM>, and thus a multi-color image is formed.

The backup roll <NUM> transfers (second transfer) the image onto the medium <NUM> by bringing the transfer surface of the intermediate transfer belt <NUM> into contact with the medium <NUM>. A predetermined voltage is applied to the backup roll <NUM> when the image is transferred. This generates an electric field (hereinafter referred to as a "transfer electric field") in a range including the backup roll <NUM> and the medium <NUM>, thereby transferring the image formed with charged particles from the intermediate transfer belt <NUM> onto the medium <NUM>. As described above, to transfer an image from the intermediate transfer belt <NUM> onto the medium <NUM>, an electric current need to flow from the backup roll <NUM> to the medium <NUM> through the intermediate transfer belt <NUM>. In a case where the medium <NUM> is a conductor such as a metal, an electric current flows through the medium <NUM> itself, and therefore an image is transferred onto a surface of the medium <NUM> by generating a transfer electric field. On the other hand, in a case where the medium <NUM> is not a conductor, no electric current flows through the medium, and therefore an image cannot be transferred in this state. In view of this, in a case where the medium <NUM> is not a conductor, an electric current is passed through the medium <NUM> by taking a measure such as forming a layer made of an electrically conductive material (hereinafter referred to as an "electrically conductive layer") in advance in at least a region on the surface of the medium <NUM> where an image is to be formed.

A procedure of transfer of an image by the intermediate transfer belt <NUM> is described. When the intermediate transfer belt <NUM> rotates, images of the respective colors: yellow (Y), magenta (M), cyan (C), and black (K) are sequentially superimposed on the transfer surface (outer surface in <FIG>) of the intermediate transfer belt <NUM> by the developing devices 110Y, <NUM>, 110C, and <NUM> and the first transfer rolls 120Y, <NUM>, 120C, and <NUM>, and thus a multi-color image is formed. When the intermediate transfer belt <NUM> further rotates, the image formed on the transfer surface of the intermediate transfer belt <NUM> reaches a position (hereinafter referred to as a "transfer position") where the intermediate transfer belt <NUM> makes contact with the medium <NUM>. As described above, a voltage is applied to the backup roll <NUM>. This generates a transfer electric field, thereby transferring the image from the intermediate transfer belt <NUM> onto the medium <NUM>.

The cleaning device <NUM> is a unit that removes particles attached to the transfer surface of the intermediate transfer belt <NUM>. The cleaning device <NUM> is provided at a position on a downstream side relative to the transfer position and an upstream side relative to the developing device 110Y and the first transfer roll 120Y in a direction in which the intermediate transfer belt <NUM> rotates. With this configuration, particles remaining on the transfer surface of the intermediate transfer belt <NUM> are removed by the cleaning device <NUM> after the image is transferred from the intermediate transfer belt <NUM> onto the medium <NUM>. In a next operation cycle, an image is newly transferred (first transfer) onto the transfer surface from which particles have been removed.

An attachment structure for attachment of the medium <NUM> is described. In the present exemplary embodiment, it is assumed that the medium <NUM> can have various thicknesses and shapes. In a case where the medium <NUM> directly placed on a transport path constituted by a belt and a roller is transported, it is difficult to appropriately bring the intermediate transfer belt <NUM> into contact with the medium <NUM> since a height of the medium <NUM> relative to the transport path varies at the transfer position of the transfer unit <NUM> in a case where a thickness and a shape of the medium <NUM> vary. Specifically, such a situation can occur in which the medium <NUM> does not make contact with the intermediate transfer belt <NUM> in a case where the height of the medium <NUM> is low, and a strong shock is caused when the medium <NUM> makes contact with the intermediate transfer belt <NUM> in a case where the height of the medium <NUM> is high. In view of this, the transport mechanism <NUM> according to the present exemplary embodiment has the attachment table <NUM> having a height controller and transports the medium <NUM> placed on the attachment table <NUM> together with the attachment table <NUM>.

The transport mechanism <NUM> includes the transport rail <NUM> that specifies a transport path for the medium <NUM> and the attachment table <NUM> that moves on the transport rail <NUM> (see <FIG>). The attachment table <NUM> includes a leg part <NUM> attached to the transport rail <NUM> and a table part <NUM> on which the medium <NUM> is to be placed. Furthermore, the jig <NUM> that holds the medium <NUM> on the table part <NUM> is attached to the table part <NUM>. The transport mechanism <NUM> is an example of a transport unit.

In the example of the configuration illustrated in <FIG>, the transport rail <NUM> is disposed so as to extend from the medium attaching detaching unit <NUM> to the transfer unit <NUM> while passing the fixing unit <NUM>. An end portion of the transport rail <NUM> on a medium attaching detaching unit <NUM> side is the transport start position and the transport end position. The attachment table <NUM> is transported leftward in <FIG> from the transport start position of the medium attaching detaching unit <NUM>, and an image is transferred onto the medium <NUM> in the transfer unit <NUM>. After the image transfer, the attachment table <NUM> is transported rightward in <FIG>, and reaches the transport end position of the medium attaching detaching unit <NUM> after the image is fixed on the medium <NUM> in the fixing unit <NUM>.

The leg part <NUM> is attached to the transport rail <NUM> and moves on the transport rail <NUM>. The leg part <NUM> is an example of a mobile part. A mechanism for moving the leg part <NUM> on the transport rail <NUM> is not limited in particular. For example, the leg part <NUM> may be provided with a driving device so as to be movable on its own or the transport rail <NUM> may be provided with a unit that pulls the leg part <NUM>. Furthermore, the leg part <NUM> has a height controller that controls a height of the table part <NUM>. A configuration of the height controller is not limited in particular. For example, the table part <NUM> may be moved up and down by rack and pinion and a drive motor. Alternatively, the height of the table part <NUM> may be controlled by manually operating a gear that is linked with the height of the table part <NUM>. Furthermore, various methods can be used as an operation method for controlling the height. For example, an input interface for input to a controller of the drive motor may be prepared, and an operator of the image forming apparatus <NUM> may manually input and set height data by using the input interface. Alternatively, the height of the medium <NUM> attached to the attachment table <NUM> may be automatically detected by using a sensor, and the drive motor may be controlled so that the medium <NUM> is located at an appropriate height.

The table part <NUM> is a table that is attached to the leg part <NUM> and on which the medium <NUM> is placed with the jig <NUM> interposed therebetween. The table part <NUM> is provided with a fastener (not illustrated) for positioning the jig <NUM>. Any jigs <NUM> compatible with this fastener can be positioned and attached to the table part <NUM> irrespective of shapes thereof.

Furthermore, the table part <NUM> is attached so as to float up and sink down with respect to the leg part <NUM> in accordance with a pressure applied from an upper side. The configuration in which the table part <NUM> floats up and sinks down is, for example, realized by interposing an elastic body at a portion where the table part <NUM> and the leg part <NUM> are joined. By employing such a configuration, a shock caused when the medium <NUM> held by the jig <NUM> attached to the table part <NUM> makes contact with the intermediate transfer belt <NUM> of the transfer unit <NUM> is lessened.

The jig <NUM> is a device for holding the medium <NUM> and is attached to the table part <NUM>. A portion of the jig <NUM> attached to the table part <NUM> has a shape and a structure compatible with the fastener of the table part <NUM>. Furthermore, the jig <NUM> has a shape for holding the medium <NUM>. Therefore, media <NUM> having various shapes and sizes can be placed on the attachment table <NUM> by preparing jigs <NUM> compatible with the shapes and sizes of the media <NUM>.

The image forming apparatus <NUM> according to the present exemplary embodiment has the transport mechanism <NUM> configured as above and therefore can print an image on any of the media <NUM> having various shapes and sizes. However, before start of image transfer operation, the height of the table part <NUM> is controlled in order to prevent a strong shock from being caused by contact of the medium <NUM> with the intermediate transfer belt <NUM> of the transfer unit <NUM> or prevent failure to bring the medium <NUM> into contact with the intermediate transfer belt <NUM> when an image is transferred onto the medium <NUM>.

<FIG> illustrate operation of the transport mechanism <NUM> before start of image formation by the transfer unit <NUM>. <FIG> illustrates how the height is controlled, <FIG> illustrates a state where the attachment table <NUM> has retreated to a preparation position after the height control, and <FIG> illustrates a state where the transfer unit <NUM> starts transfer of an image.

In a case where an image is formed on the medium <NUM>, first, the medium <NUM> held by the jig <NUM> is placed on the attachment table <NUM> at the transport start position of the medium attaching detaching unit <NUM>. Then, the medium <NUM> is lowered to a height at which the medium <NUM> does not make contact with the intermediate transfer belt <NUM> of the transfer unit <NUM> by the height controller of the attachment table <NUM>, and then the attachment table <NUM> on which the medium <NUM> is placed is moved to a position below the transfer position of the transfer unit <NUM>.

Next, the height of the attachment table <NUM> is controlled so that the medium <NUM> makes contact with the intermediate transfer belt <NUM> with a strength appropriate for transfer of the image at the transfer position (arrow a in <FIG>). When the height is controlled, information on an appropriate height (hereinafter referred to as a "transfer execution height") thus obtained is held, for example, in the memory of the controller. Then, the attachment table <NUM> is lowered to a height where the medium <NUM> does not make contact with the intermediate transfer belt <NUM> and moves to the preparation position for transfer operation (arrow b in <FIG>).

When the attachment table <NUM> moves to the preparation position, the height of the attachment table <NUM> is adjusted to the transfer execution height on the basis of the information obtained in the height control. Then, the attachment table <NUM> moves to the transfer position (arrow c in <FIG>), and transfer of the image starts when the medium <NUM> makes contact with the intermediate transfer belt <NUM> at the transfer position (<FIG>).

After the image is transferred onto the medium <NUM> in the transfer unit <NUM>, the image is fixed in the fixing unit <NUM>. In the present exemplary embodiment, an image is formed on any of the media <NUM> having various thicknesses and shapes, and therefore the fixing processing is performed by a non-contact-type device. The fixing unit <NUM> melts particles forming the image transferred onto the medium <NUM> by heating the particles and thereby fixes the particles on the surface of the medium <NUM>.

<FIG> illustrate a configuration and operation of the fixing unit <NUM>. <FIG> illustrates a state where openings of the fixing unit <NUM> are closed, and <FIG> illustrates a state where the openings of the fixing unit <NUM> are opened. The fixing unit <NUM> includes a carry-in opening <NUM>, which is an opening through which the medium <NUM> is carried into the fixing unit <NUM>, and a carry-out opening <NUM>, which is an opening through which the medium <NUM> is carried out of the fixing unit <NUM>. Furthermore, the carry-in opening <NUM> and the carry-out opening <NUM> of the fixing unit <NUM> according to the present exemplary embodiment are provided with an opening and closing member and are configured to be opened when the medium <NUM> is carried into or out of the fixing unit <NUM> and be closed when the fixing processing is performed.

In this example, an opening on a side where the medium <NUM> is carried into the fixing unit <NUM> when image fixing processing is performed by the fixing unit <NUM> is the carry-in opening <NUM>, and an opening on a side where the medium <NUM> is carried out of the fixing unit <NUM> is the carry-out opening <NUM>. In other words, an opening in a side surface that faces the transfer unit <NUM> is the carry-in opening <NUM>, and an opening in a side surface that faces the medium attaching detaching unit <NUM> is the carry-out opening <NUM>. In the example illustrated in <FIG>, an opening on a left side is the carry-in opening <NUM>, and an opening on a right side is the carry-out opening <NUM>. In the image forming apparatus <NUM> according to the present exemplary embodiment, the medium <NUM> passes through the fixing unit <NUM> when the medium <NUM> is transported from the transport start position of the medium attaching detaching unit <NUM> to the transfer unit <NUM>. In this case, the medium <NUM> enters the fixing unit <NUM> through the carry-out opening <NUM> and exits the fixing unit <NUM> through the carry-in opening <NUM>, in a manner opposite to the case where the fixing processing is performed. However, in the present exemplary embodiment, the carry-in opening <NUM> and the carry-out opening <NUM> are set as described above on the basis of operation performed when the fixing processing is performed in the fixing unit <NUM>.

The fixing unit <NUM> includes a heat source <NUM> for thermal fixation. The heat source <NUM> can be, for example, any of various existing heat sources such as a halogen lamp, a ceramic heater, and an infrared lamp. Instead of the heat source <NUM>, a device that heats particles forming the image by emitting infrared laser may be used. The fixing unit <NUM> according to the present exemplary embodiment is provided with a member that can cover the heat source <NUM>, and is configured so that the heat source <NUM> is exposed when the fixing processing is performed.

In the example illustrated in <FIG>, roll-up shutters <NUM> and <NUM> are provided as the opening and closing members of the carry-in opening <NUM> and the carry-out opening <NUM>. The shutters <NUM> and <NUM> are closed (see <FIG>) except when the medium <NUM> is carried into and out of the fixing unit <NUM> and thereby prevent a decrease in internal temperature. The shutter <NUM> of the carry-in opening <NUM> opens when the medium <NUM> is carried into the fixing unit <NUM>, and the shutter <NUM> of the carry-out opening <NUM> opens when the medium <NUM> is carried out of the fixing unit <NUM> (see <FIG>).

In the example illustrated in <FIG>, a roll-up shutter <NUM> is provided as the covering member that covers the heat source <NUM>. The shutter <NUM> closes in a case where the shutter <NUM> of the carry-in opening <NUM> and/or the shutter <NUM> of the carry-out opening <NUM> open(s) (see <FIG>). This may keep a decrease in temperature of the heat source <NUM> small even in a case where the carry-in opening <NUM> and/or the carry-out opening <NUM> open(s) and the internal temperature decreases.

In the example illustrated in <FIG>, a state where both of the shutter <NUM> of the carry-in opening <NUM> and the shutter <NUM> of the carry-out opening <NUM> are opened is illustrated for convenience of description. In actual operation, the shutter <NUM> of the carry-out opening <NUM> remains closed when the medium <NUM> is carried into the fixing unit <NUM>, and the shutter <NUM> of the carry-in opening <NUM> remains closed when the medium <NUM> is carried out of the fixing unit <NUM>. This keeps a decrease in internal temperature small.

The shutters <NUM>, <NUM>, and <NUM> illustrated in <FIG> are an example of the opening and closing members of the carry-in opening <NUM> and the carry-out opening <NUM> and the covering member of the heat source <NUM>. The opening and closing members and covering member are not limited to the above configuration, as long as the opening and closing members and covering member keep a decrease in internal temperature of the fixing unit <NUM> and temperature of the heat source <NUM> small. For example, an opening and closing door may be provided instead of the shutters <NUM>, <NUM>, and <NUM> illustrated in <FIG>. As the opening and closing member of the carry-out opening <NUM> through which the medium <NUM> passes after the fixing processing is finished, a curtain made of a heat insulating material or air curtain may be used to prevent leakage of internal air. Configuration of Attachment Table <NUM>.

Next, a configuration of the attachment table <NUM> is described in more detail. As described with reference to <FIG>, the image forming apparatus <NUM> according to the present exemplary embodiment transfers an image formed on the intermediate transfer belt <NUM> of the transfer unit <NUM> onto the medium <NUM> by bringing the intermediate transfer belt <NUM> into contact with the medium <NUM>. Furthermore, as described above, the elastic body is interposed between the leg part <NUM> and the table part <NUM> of the attachment table <NUM> so that the table part <NUM> floats up and sinks down, and thereby a shock caused by contact of the medium <NUM> with the intermediate transfer belt <NUM> is lessened. In other words, the attachment table <NUM> changes a height thereof in accordance with force by which the intermediate transfer belt <NUM> makes contact with the medium <NUM>. This configuration for changing the height of the table part <NUM> is described by giving a specific example.

<FIG> illustrate a structure of the attachment table <NUM>. <FIG> illustrates a first configuration example, and <FIG> illustrates a second configuration example. In the first configuration example illustrated in <FIG>, the table part <NUM> is supported on an upper surface of the leg part <NUM> with use of plural springs <NUM>. The springs <NUM> are compression springs, and are coiled springs in the example illustrated in <FIG>. When the attachment table <NUM> receives a pressure from an upper side, the springs <NUM> contract in accordance with the received pressure, and thereby the table part <NUM> sinks down. When the pressure from the upper side acting on the attachment table <NUM> decreases, the table part <NUM> is pushed up due to repulsion of the springs <NUM>. The plural springs <NUM> are independent of one another and individually support the table part <NUM>. Accordingly, the table part <NUM> is inclined depending on a position where a pressure is received instead of merely sinking down. The springs <NUM> are an example of the elastic body.

In the second configuration example illustrated in <FIG>, an elastic sheet <NUM> is provided between the table part <NUM> and the leg part <NUM>. In a case where the sheet <NUM> is interposed between the table part <NUM> and the leg part <NUM>, when the attachment table <NUM> receives a pressure from an upper side, the sheet <NUM> is crushed in accordance with the received pressure, and the table part <NUM> sinks down accordingly. When the pressure from the upper side acting on the attachment table <NUM> decreases, the table part <NUM> is pushed up due to elasticity of the sheet <NUM>. The sheet <NUM> is partially crushed in accordance with a local pressure at and around a portion receiving the pressure. Accordingly, the table part <NUM> is inclined depending on a position where a pressure is received instead of merely sinking down. Although a single plate-shaped sheet <NUM> is illustrated in the example illustrated in <FIG>, plural sheets made of different materials may be laminated to obtain elasticity and flexibility suitable for supporting the table part <NUM>. The sheet <NUM> is an example of the elastic member.

<FIG> illustrate how the height of the attachment table <NUM> changes when transfer is performed. <FIG> illustrates a state at start of the transfer, <FIG> illustrates a state during the transfer, and <FIG> illustrates a state at end of the transfer. <FIG> illustrates an example in which the attachment table <NUM> in which the table part <NUM> is supported with the use of the springs <NUM> illustrated in <FIG> is used. In the example illustrated in <FIG>, a case where the transfer unit <NUM> transfers an image by making contact with the medium <NUM> as the attachment table <NUM> on which the medium <NUM> is placed moves from left to right (see the arrows) in <FIG> is illustrated.

At the start of the transfer, first, a leading end portion of the medium <NUM> in the transport direction makes contact with the intermediate transfer belt <NUM> of the transfer unit <NUM>. Since the position of the intermediate transfer belt <NUM> is fixed by the backup roll <NUM>, a portion of the medium <NUM> with which the intermediate transfer belt <NUM> makes contact receives a downward pressure when the intermediate transfer belt <NUM> and the medium <NUM> make contact with each other. As a result, a front end side of the table part <NUM> of the attachment table <NUM> in the transport direction sinks down due to the springs <NUM>, and the whole table part <NUM> is inclined, as illustrated in <FIG>.

When the transfer of the image onto the medium <NUM> proceeds, a position of contact of the medium <NUM> with the intermediate transfer belt <NUM> moves in a direction opposite to the transfer direction. Accordingly, as illustrated in <FIG>, the whole table part <NUM> of the attachment table <NUM> sinks down due to the springs <NUM>. Then, at the end of the transfer, a rear end side of the table part <NUM> of the attachment table <NUM> in the transport direction sinks down, and the whole table part <NUM> is inclined, as illustrated in <FIG>.

The table part <NUM> of the attachment table <NUM> changes the height thereof while being inclined in accordance with force applied by contact between the transfer unit <NUM> and the medium <NUM> as described above, and thereby force by which the transfer unit <NUM> pushes the medium <NUM> when an image is transferred falls within a certain range. Furthermore, a shock caused when the transfer unit <NUM> makes contact with the medium <NUM> is lessened.

The image forming apparatus <NUM> according to the present exemplary embodiment attaches the medium <NUM> to the attachment table <NUM> by holding the medium <NUM> on the jig <NUM> configured according to a shape and a size of the medium <NUM> and attaching the jig <NUM> to the table part <NUM>. The jig <NUM> holds the medium <NUM> by fastening at least a portion of the medium <NUM> other than a surface onto which an image is to be transferred. The jig <NUM> may be any jig that stably attaches the medium <NUM> to the attachment table <NUM>, and is configured in various manners in accordance with the shape and size of the medium <NUM>. The jig <NUM> is described below by giving some specific examples.

<FIG> illustrate a first configuration example of the jig <NUM>. Fig. A is a side view, and <FIG> is a plan view. The jig <NUM> includes a base plate 423a on which the medium <NUM> is placed and a fastening part 423b that fastens the medium <NUM> placed on the base plate 423a. The fastening part 423b is provided so as to fasten and fix the medium <NUM> at least from a front side in the transport direction in a state where the medium <NUM> is placed on the base plate 423a. In the configuration example illustrated in <FIG>, the jig <NUM> fixes the medium <NUM> by fastening the medium <NUM> from front and rear sides in the transport direction (from left and right in <FIG>). In this way, the position of the medium <NUM> is less likely to be shifted in the transport direction due to a shock caused by contact between the transfer unit <NUM> and the medium <NUM>.

Furthermore, the fastening part 423b of the jig <NUM> has a specific height according to the height of the medium <NUM> placed on the base plate 423a. Since the table part <NUM> of the attachment table <NUM> floats up and sinks down as described with reference to <FIG> and <FIG> when an image is transferred onto the medium <NUM> by the transfer unit <NUM>, the intermediate transfer belt <NUM> first makes contact with the fastening part 423b of the jig <NUM> on the front side in the transport direction and then makes contact with the medium <NUM>. Accordingly, the height of the fastening part 423b is set to such a degree that a shock caused by contact of the transfer unit <NUM> does not affect an image formed on the intermediate transfer belt <NUM>.

<FIG> illustrate how the jig <NUM> and the medium <NUM> make contact with the intermediate transfer belt <NUM> of the transfer unit <NUM> at the start of transfer. <FIG> illustrates a state where the jig <NUM> and the intermediate transfer belt <NUM> are in contact with each other, and <FIG> illustrates a state where the medium <NUM> and the intermediate transfer belt <NUM> are in contact with each other. As illustrated in <FIG>, when the jig <NUM> holding the medium <NUM> is attached to the table part <NUM> of the attachment table <NUM> and is transported, first, the fastening part 423b of the jig <NUM> on the front side in the transport direction makes contact with the intermediate transfer belt <NUM> (<FIG>). Then, when the attachment table <NUM> further moves, an end portion of the medium <NUM> on the front side in the transport direction makes contact with the intermediate transfer belt <NUM> (<FIG>), and transfer of an image starts. If a difference in height between the medium <NUM> and the fastening part 423b is large, a shock caused by the contact is large on both of the medium <NUM> and the intermediate transfer belt <NUM>. In view of this, the difference in height between the medium <NUM> and the fastening part 423b is set equal to or less than a certain value. For example, an upper limit of the difference in height between the medium <NUM> and the fastening part 423b may be a smaller one of <NUM>/<NUM> of the height of the medium <NUM> and <NUM>.

<FIG> illustrate a second configuration example of the jig <NUM>. <FIG> is a side view, and <FIG> is a plan view. In the example illustrated in <FIG>, the medium <NUM> is a plate-shaped member and has a protruding portion on one surface side, and an image is formed on the other surface side. An example of such a medium <NUM> is a name tag having, on a rear surface thereof, an attachment part to be attached to clothes or the like. The jig <NUM> illustrated in <FIG> has, on the base plate 423a, a groove 423c in which the protruding portion of the medium <NUM> is accommodated. Although a space for evacuation of the protruding portion on the one surface of the medium <NUM> is created by the groove 423c provided on the base plate 423a of the jig <NUM> in the example illustrated in <FIG>, the protruding portion of the medium <NUM> may be fixed by the groove 423c. For example, the groove 423c may include a claw that is caught on the protruding portion of the medium <NUM> or a gripping unit that grips the protruding portion of the medium <NUM>, and the medium <NUM> may be fixed to the jig <NUM> by fitting the protruding portion into the groove 423c.

<FIG> illustrate a third configuration example of the jig <NUM>. <FIG> is a side view, and <FIG> is a plan view. In the example illustrated in <FIG>, an end portion of the fastening part 423b on a side that does not make contact with the medium <NUM> is inclined. Specifically, the fastening part 423b of the jig <NUM> on the front side in the transport direction is inclined downward toward the front side in the transport direction, and the fastening part 423b of the jig <NUM> on the rear side in the transport direction is inclined downward toward the rear side in the transport direction. According to such a configuration, a shock caused when the fastening part 423b and the intermediate transfer belt <NUM> of the transfer unit <NUM> make contact is further lessened, as described with reference to <FIG>. Although both of the fastening part 423b on the front side and the fastening part 423b on the rear side of the medium <NUM> in the transport direction are inclined in the example illustrated in <FIG>, it is only necessary that the fastening part 423b on the front side in the transport direction is inclined.

<FIG> illustrate a fourth configuration example of the jig <NUM>. <FIG> is a side view, and <FIG> is a plan view. In the example illustrated in <FIG>, it is assumed that at least end portions of the medium <NUM> on the front side and the rear side in the transport direction cannot be exposed when an image is transferred. In this case, one option is to hold the medium <NUM> by the jig <NUM> having the fastening parts 423b whose height is equal to or higher than a height of the end portions of the medium <NUM>, as illustrated in <FIG>. The image forming apparatus <NUM> according to the present exemplary embodiment can transfer an image even in a case where the height of the fastening parts 423b is higher than the height of the end portions of the medium <NUM> as illustrated in <FIG> since the table part <NUM> of the attachment table <NUM> floats up and sinks down as described with reference to <FIG> and <FIG>.

<FIG> illustrate how the jig <NUM> and the medium <NUM> make contact with the intermediate transfer belt <NUM> of the transfer unit <NUM> in a case where the jig <NUM> according to the fourth configuration example is used. <FIG> illustrates a state where the jig <NUM> and the intermediate transfer belt <NUM> are in contact with each other, and <FIG> illustrates a state where the medium <NUM> and the intermediate transfer belt <NUM> are in contact with each other. As illustrated in <FIG>, when the jig <NUM> holding the medium <NUM> is attached to the table part <NUM> of the attachment table <NUM> and is transported, first, the fastening part 423b of the jig <NUM> on the front side in the transport direction makes contact with the intermediate transfer belt <NUM> (<FIG>). Then, when the attachment table <NUM> further moves, the medium <NUM> makes contact with the intermediate transfer belt <NUM> (<FIG>), and transfer of an image starts. Since the table part <NUM> of the attachment table <NUM> is pushed up due to repulsive force of the springs <NUM> or the sheet <NUM> described with reference to <FIG> and <FIG>, even the medium <NUM> whose height is lower than the fastening part 423b of the jig <NUM> makes contact with the intermediate transfer belt <NUM>.

Also in the example illustrated in <FIG>, if a difference in height between the medium <NUM> and the fastening part 423b is large, a shock caused when the medium <NUM> and the intermediate transfer belt <NUM> make contact with each other is large although the shock is not as large as that in the example described with reference to <FIG>. In view of this, the difference in height between the medium <NUM> and the fastening part 423b is set equal to or smaller than a certain value. For example, an upper limit of the difference in height between the medium <NUM> and the fastening part 423b may be a smaller one of <NUM>/<NUM> of the height of the medium <NUM> and <NUM>. Furthermore, in the example illustrated in <FIG>, an end portion of the fastening part 423b of the jig <NUM> on a side that makes contact with the medium <NUM> is inclined. With this configuration, a shock caused when the fastening part 423b and the medium <NUM> make contact with each other is further lessened.

Although the jig <NUM> can have shapes corresponding to the individual media <NUM>, a uniform attachment structure is employed for attachment to the table part <NUM> of the attachment table <NUM>. This makes it possible to attach the media <NUM> having various shapes and sizes to the attachment table <NUM> by interposing the jig <NUM> therebetween. The attachment structure of the jig <NUM> is not limited in particular, as long as the attachment structure is a structure that positions and fixes the jig <NUM> on the table part <NUM>. As an example, one or both of the table part <NUM> and the jig <NUM> may be provided with a fastener or the like so as to be engaged with each other and fixed. The following describes the attachment structure of the jig <NUM> using a fastener by giving some specific examples.

<FIG> illustrate an example of a fastener that attaches the jig <NUM> to the table part <NUM> of the attachment table <NUM>. <FIG> is a side view, and <FIG> is a plan view. In the example illustrated in <FIG>, a butting part 422a that fastens an outer periphery of the jig <NUM> is provided as the fastener on the table part <NUM>. In this example, it is assumed that an external shape of the jig <NUM> is rectangular. The butting part 422a stands on an upper surface of the table part <NUM> at positions corresponding to four corners of the jig <NUM> in a state where the jig <NUM> is placed on the table part <NUM>. As illustrated in <FIG>, each of the butting parts 422a has an L shape that matches a corresponding corner of the jig <NUM>. The four corners of the jig <NUM> are accommodated within these four butting parts 422a, and thereby the jig <NUM> is positioned on the table part <NUM>, and movement of the jig <NUM> in a direction parallel with the surface of the table part <NUM> is regulated. In a case where the jig <NUM> is attached to the table part <NUM>, the jig <NUM> is placed from above the table part <NUM> while adjusting positions of the corners of the jig <NUM> so that the jig <NUM> is accommodated within the four butting parts 422a.

Although the butting parts 422a are disposed corresponding to the four corners of the jig <NUM> in the example illustrated in <FIG>, layout of the butting parts 422a is not limited to the example illustrated in <FIG> as long as the jig <NUM> is positioned and movement thereof is regulated. For example, plate-shaped butting parts 422a may be disposed at positions corresponding to four sides of the jig <NUM> in a state where the jig <NUM> is placed on the table part <NUM>. Even in a case where the external shape of the jig <NUM> is a shape other than a rectangular shape, the jig <NUM> can be attached to the table part <NUM> by disposing the butting parts 422a in accordance with the shape.

<FIG> illustrate another example of a fastener that attaches the jig <NUM> to the table part <NUM> of the attachment table <NUM>. <FIG> is a side view, and <FIG> is a plan view. In the example illustrated in <FIG>, a pin 422b that connects the table part <NUM> and the jig <NUM> is provided as the fastener. In this example, a hole is provided at each of positions of the table part <NUM> and corresponding positions of the jig <NUM>. One end side of the pin 422b is inserted into each of the holes of the table part <NUM>, and the other end side of the pin 422b is inserted into a corresponding hole of the jig <NUM>. In this way, the jig <NUM> is positioned on the table part <NUM>, and movement thereof in a direction parallel with the surface of the table part <NUM> is regulated. In a case where the jig <NUM> is attached to the table part <NUM>, the pin 422b is inserted into each of the holes of the table part <NUM>, and the jig <NUM> is placed on the table part <NUM> while adjusting the positions of the holes of the jig <NUM> to the positions of the pins 422b.

In the example illustrated in <FIG>, holes are provided in both of the table part <NUM> and the jig <NUM>, and the pins 422b are inserted into the holes. Alternatively, it is also possible to employ a configuration in which a protruding pin 422b is provided on the upper surface of the table part <NUM> and the pin 422b is inserted into a hole formed in the jig <NUM> corresponding to the position of the pin 422b. Conversely, it is also possible to employ a configuration in which a protruding pin 422b is provided on a lower surface of the jig <NUM> and the pin 422b is inserted into a hole formed in the table part <NUM> corresponding to the position of the pin 422b. Although the pins 422b and holes are disposed so that the four pins 422b form four vertexes of a rectangle in the example illustrated in <FIG>, layout of the pins 422b is not limited to the example illustrated in <FIG>, as long as the jig <NUM> is positioned and movement thereof is regulated. In a case where the pins 422b are used as the fastener, the external shape of the jig <NUM> is not restricted since the outer peripheral part of the jig <NUM> is not fastened unlike the butting parts 422a described with reference to <FIG>.

<FIG> illustrate another example of the fastener that attaches the jig <NUM> to the table part <NUM> of the attachment table <NUM>. <FIG> is a side view, and <FIG> is a plan view. In the example illustrated in <FIG>, a claw 422c that is caught on the outer peripheral part of the jig <NUM> is provided as the fastener on the table part <NUM>. In this example, it is assumed that the external shape of the jig <NUM> is rectangular. The jig <NUM> has, on a front side and a rear side in the transport direction on the outer circumference of the jig <NUM>, a protruding side 423d on which the claw 422c is caught. The claw 422c is located so as to fasten the protruding side 423d of the jig <NUM> from the front and rear sides in the transport direction in a state where the jig <NUM> is placed on the table part <NUM>. The claws 422c are configured to open upward in sync with one another or individually. By placing the jig <NUM> on the table part <NUM> and then closing the claws 422c, the jig <NUM> is positioned on the table part <NUM>, and movement of the jig <NUM> in the transport direction and in an upward direction is regulated.

Although the claws 422c fasten the jig <NUM> from the front and rear sides in the transport direction in the example illustrated in <FIG>, a claw 422c that fastens the jig <NUM> from a direction crossing the transport direction may be additionally provided. Furthermore, although the protruding side 423d of the jig <NUM> is provided throughout sides of the jig <NUM> on the front and rear sides in the transport direction in the example illustrated in <FIG>, the protruding side 423d may be provided only at positions fastened by the claws 422c.

Claim 1:
An image forming apparatus (<NUM>) comprising:
a transfer unit (<NUM>) configured to transfer an image onto an object (<NUM>) by making contact with the object (<NUM>);
an attachment table (<NUM>) to which the object (<NUM>) is attached and that is configured to change a height thereof in accordance with force by which the transfer unit (<NUM>) makes contact with the object (<NUM>); and
a transport unit (<NUM>) configured to transport the attachment table (<NUM>) to which the object (<NUM>) has been attached along a transport path,
the image forming apparatus (<NUM>) being characterized by:
further comprising a jig (<NUM>) configured to fasten at least a portion of the object (<NUM>) other than a surface on which an image is to be transferred,
and in that the attachment table (<NUM>) includes a fastener configured to position and fixes the jig (<NUM>), and a portion of the jig (<NUM>) located on the front side in a transport direction in which the object (<NUM>) is transported by the transport unit (<NUM>) is inclined downward toward the front side in the transport direction.