Patent Description:
In recent years, images may be printed, for example, on metal, glass, and tile (hereinafter referred to as "objects"). These objects have various thicknesses and shapes. Therefore, the image quality of the objects needs to be checked, and the settings of the objects need to be adjusted.

A technique of the related art is disclosed in <CIT>.

In an existing image forming system, a transferred image is fixed onto an object even in image quality adjustment. However, the per-unit price of metal, glass, tile, or the like is more expensive than that of paper. Therefore, disposal of objects used in image quality adjustment causes a large burden in view of cost. <CIT> discloses a shutter device for a fixing device which applies predetermined heat and pressure to an image forming medium that is transferred after a developer is attached in correspondence with an electrostatic latent image. In the fixing unit of the image forming apparatus which fixes the formed image by fixing the formed image, a means for covering the area other than the entrance for the image forming medium in a substantially tight funnel shape, and a shutter. <CIT> discloses an image forming apparatus including a recording material feeding portion; an image forming portion configured to form an image with a liquid developer containing toner and an ultraviolet curable agent; an ultraviolet irradiating portion; a heating portion configured to heat the recording material on a feeding path of the recording material from a recording material feeding position where the recording material feeding portion feeds the recording material to an ultraviolet irradiation position. <CIT> discloses a transportation device including a first transporter, a second transporter movable between a contact position and a separate position toward and away from the first transporter to hold a to-be-transported object between the second transporter and the first transporter in the contact position, and a transportation unit that transports the to-be-transported object to a nip area where the first transporter and the second transporter hold the to-be-transported object therebetween while the second transporter is located in the separate position. <CIT> discloses an image forming apparatus with a sheet supply cassette which can contain a plurality of recording members and can be removably mounted within the image forming apparatus, an image forming device for forming an image on the recording member with toner to form a toner image, fixing rollers having a heater for thermally fixing the toner image on the recording member, remaining amount detecter means. <CIT> discloses an electrophotographic machine having a transfer paper fixing mode and an unfixing mode. When a toner image is fixed on transfer paper, a discharge part is placed in a state that the upper surface of a transportation belt and a discharge roll, and the upper surface of the transportation belt are not positioned on the same plane, and a control circuit attain a fixing mode. When the transfer paper is discharged in an unfixed state, the upper surface of the transportation belt is positioned so as to be positioned on almost the same horizontal surface as the upper surface of the transportation belt, also a discharge roll is spaced from the discharge roll, the control circuit attains a non-fixing mode, a fixing operation inhibiting signal is applied to a fixing device, and the transportation belt operates from the time point when the tip of the transfer paper reaches the discharge part to stop the transportation feet at the time point when the rear end of unfixed transfer paper reaches the discharge part. <CIT> discloses a composite image forming apparatus employing a combination of an inkjet printing method and an electrophotographic printing method and a printing method using the same. <CIT> discloses a recording apparatus having an emergency stop function for stopping the driving of the recording apparatus from the outside. When an instruction for an emergency stop is received during the paper transporting operation, a process is immediately performed by regarding a jam.

The following disclosure serves a better understanding of the present invention. Accordingly, it is an object of the present disclosure to provide a technique for achieving reduction of wasteful objects compared with the case in which an image transferred for image quality adjustment is fixed onto an object.

The invention is defined by independent claims <NUM> and <NUM>, dependent claims <NUM>-<NUM> define preferred embodiments.

The subject-matter of claims <NUM> and <NUM> each enable reduction of wasteful objects compared with the case in which a transferred image is fixed onto an object even in the image-quality adjustment mode.

The subject-matter of claim <NUM> enables reliable avoidance of an unintended operation of fixing an image.

The subject-matter of claims <NUM> and <NUM> each further enable a worker not to need to specify the adjustment mode.

Referring to the drawings, exemplary embodiments of the present disclosure will be described below.

<FIG> is a diagram for describing a schematic configuration of an image forming apparatus <NUM> which is assumed in a first exemplary embodiment. The image forming apparatus <NUM> is an exemplary image forming system.

In the first exemplary embodiment, an object to be printed on is referred to as a medium <NUM>. The material of a medium <NUM> is, for example, metal, glass, tile, ceramic, or wood, and has a standardized size. That is, the image forming apparatus <NUM> in the first exemplary embodiment forms images, one by one, on the surfaces of media <NUM> having the same material and shape. <FIG> illustrates the case of a flat-shaped medium <NUM>.

In the first exemplary embodiment, a length in the Z-axis direction in the figures is referred to as a "height" or "thickness"; transporting a medium <NUM> in the Z-axis direction is referred to as "raising/lowering".

A plane defined by the X axis and the Y axis in the figures is horizontal to the floor. In the first exemplary embodiment, transporting a medium <NUM> in the X-axis direction is referred to as "transporting in the horizontal direction".

The image forming apparatus <NUM> illustrated in <FIG> includes three housings 10A, 10B, and 10C. The image forming apparatus <NUM> may appear as if it has a single housing.

The housing 10A contains a transfer unit <NUM> and a processing unit <NUM>. The housing 10B contains a fixing unit <NUM>. The housing 10C is provided to take in and out a medium <NUM>. To do this, an opening (not illustrated) is disposed on the top surface of the housing 10C.

The image forming apparatus <NUM> includes a transporter <NUM> which extends across the three housings 10A, 10B, and 10C. The transporter <NUM> is an exemplary transporter.

The transfer unit <NUM> transfers, onto a medium <NUM>, an image formed by using toner or powder particles. That is, the transfer unit <NUM> in the first exemplary embodiment forms an image by using an electrophotographic system.

The fixing unit <NUM> heats toner or the like, which has been transferred by the transfer unit <NUM>, to fix the toner or the like onto the surface of the medium <NUM>. The first exemplary embodiment employs a contactless heating system. In the first exemplary embodiment, a heat source is used to heat the surface of a medium <NUM> and the toner or the like at the same time.

<FIG> is a diagram illustrating an exemplary configuration of the transfer unit <NUM>. The transfer unit <NUM> forms an image with charged particles, and generates an electric field to transfer the image onto a medium <NUM>.

The transfer unit <NUM> includes developing devices <NUM>, first-transfer rolls <NUM>, and an intermediate transfer belt <NUM>. The intermediate transfer belt <NUM>, which is stretched around driving rolls <NUM> and <NUM> and a backup roll <NUM>, travels cyclically.

Additionally, the transfer unit <NUM> has a cleaning device <NUM> which removes particles having been attached to the intermediate transfer belt <NUM>.

Each developing device <NUM> is a unit which forms an electrostatic latent image of an image on its photoreceptor, and which attaches charged particles to the electrostatic latent image on the photoreceptor to develop the image. The developing devices <NUM> illustrated in <FIG> support four colors, which are black as well as three colors of yellow, magenta, and cyan.

In <FIG>, units corresponding to the colors of yellow, magenta, cyan, and black are labeled with Y, M, C, and K indicating the respective colors. When the colors are not necessary to be discriminated, the units are not labeled with Y, M, C, and K.

The first-transfer rolls <NUM> are used to transfer, onto the intermediate transfer belt <NUM>, images formed on the developing devices <NUM>. The transfer using the first-transfer rolls <NUM> is called "first transfer".

The first-transfer rolls <NUM> are disposed so as to be opposite the respective developing devices <NUM> with the intermediate transfer belt <NUM> interposed in between. The first-transfer rolls <NUM> bring the outer surface of the intermediate transfer belt <NUM> in contact with the developing devices <NUM>.

The first-transfer rolls <NUM> are provided for the respective developing devices 110Y, <NUM>, 110C, and <NUM>. <FIG> illustrates the first-transfer rolls <NUM>, which correspond to the respective colors, with the labels of 120Y, <NUM>, 120C, and <NUM>.

In <FIG>, the intermediate transfer belt <NUM> travels in the direction indicated by the arrow (that is, the counterclockwise direction). For example, either one or both of the driving rolls <NUM> and <NUM> cause the intermediate transfer belt <NUM> to travel.

In <FIG>, images formed by the developing devices <NUM> are transferred onto the outer surface of the intermediate transfer belt <NUM>. That is, the intermediate transfer belt <NUM> holds formed images. Hereinafter, the outer surface of the intermediate transfer belt <NUM> is referred to as a "transfer surface".

In the configuration illustrated in <FIG>, the intermediate transfer belt <NUM> passes the developing devices 110Y, <NUM>, 110C, and <NUM> sequentially so that a multicolor image, in which yellow, magenta, cyan, and black are stacked on the transfer surface from the bottom layer in this sequence, is formed.

The backup roll <NUM> is a roller which brings the transfer surface of the intermediate transfer belt <NUM> in contact with a medium <NUM> to transfer the image onto the surface of the medium <NUM>. The transfer using the backup roll <NUM> is called "second transfer".

In second transfer, a predetermined voltage is applied to the backup roll <NUM>. Application of the voltage causes an electric field (hereinafter referred to as a "transfer electric field") to occur between the backup roll <NUM> and a medium <NUM> so that the image formed with charged particles is transferred from the intermediate transfer belt <NUM> to the medium <NUM>.

Thus, transfer of an image from the intermediate transfer belt <NUM> to a medium <NUM> needs a current which flows from the backup roll <NUM> through the intermediate transfer belt <NUM> to the medium <NUM>.

When a medium <NUM> is a conductor such as metal, since a current flows through the medium <NUM> itself, an image is transferred onto the surface of the medium <NUM> through occurrence of a transfer electric field.

In contrast, when a medium <NUM> is a nonconductor, an image is not transferred onto the surface of the medium <NUM> unless additional configuration is provided. Therefore, when a medium <NUM> is a nonconductor, a layer (hereinafter referred to as a "conductive layer") of a conductive member is formed in advance at least in a portion, in which an image is to be formed, to provide a path through which a current flows. Thus, an image may be also transferred onto a nonconductor.

The procedure of image transfer using the intermediate transfer belt <NUM> will be described simply.

Images of the colors are sequentially transferred onto the transfer surface of the intermediate transfer belt <NUM> passing the developing devices 110Y, <NUM>, 110C, and <NUM>. As a result, a multicolor image is held on the transfer surface of the intermediate transfer belt <NUM>.

When the intermediate transfer belt <NUM> further rotates, the multicolor image held on the transfer surface of the intermediate transfer belt <NUM> reaches the position (hereinafter referred to as the "transfer position") where the multicolor image is in contact with a medium <NUM>.

In this state, when the voltage is applied to the backup roll <NUM> and a transfer electric field occurs, the image is transferred from the intermediate transfer belt <NUM> to the medium <NUM>.

The cleaning device <NUM> is a unit which removes particles remaining on the transfer surface of the intermediate transfer belt <NUM> which has passed the transfer position.

The cleaning device <NUM> is disposed between the transfer position and the developing device 110Y in the rotation direction of the intermediate transfer belt <NUM>. In other words, the cleaning device <NUM> is disposed downstream of the transfer position and upstream of the developing device 110Y.

Removal of particles by the cleaning device <NUM> provides preparation for the next cycle. That is, transfer of a new image onto the transfer surface is ready.

An exemplary configuration of the transporter <NUM> which transports a medium <NUM> will be described.

As described above, the image forming apparatus <NUM> in the first exemplary embodiment is used to form images on media <NUM> having various thicknesses. Therefore, the height of the mounting surface on the transporter <NUM> side needs to be adjusted.

Thus, the transporter <NUM> in the first exemplary embodiment has a mechanism for raising/lowering a medium <NUM> in the vertical direction in addition to a mechanism for transporting a medium <NUM> in the horizontal direction.

In <FIG>, the transporter <NUM> (see <FIG>) includes a transport rail <NUM> which defines a transport path for a medium <NUM>, and a mount <NUM> which moves along the transport rail <NUM>.

The mount <NUM> has a leg <NUM> which moves along the transport rail <NUM>, and a pedestal <NUM> on which a medium <NUM> is mounted. Among these, the leg <NUM> has a mechanism for raising/lowering the pedestal <NUM> in the vertical direction. In this sense, the leg <NUM> is an exemplary transporter and an exemplary raising/lowering unit. In a broad sense, the leg <NUM> and the pedestal <NUM> are referred to as a transporter.

On the pedestal <NUM>, a medium <NUM> may be mounted directly, or a jig <NUM> may be mounted. The jig <NUM> is a member used to hold a medium <NUM>, and is mounted on the mounting surface of the pedestal <NUM> for use. Therefore, the jig <NUM> may be freely attached to/detached from the mounting surface of the pedestal <NUM>.

The transport rail <NUM> is installed through the three housings 10A to 10C.

The transport rail <NUM> has one end portion disposed in the housing 10C where a transport operation starts and where a transport operation ends. The transport rail <NUM> has the other end portion disposed in the housing 10A in which the transfer unit <NUM> is disposed.

The mount <NUM>, on which a medium <NUM> is mounted, is transported from the housing 10C, in which one end portion is present, to the housing 10A, in which the other end portion is present. In the transport operation, an operation of adjusting the height of the top of the medium <NUM> to the elevation of the intermediate transfer belt <NUM> is also performed. The end portion of the transport rail <NUM> in the housing 10A is spaced apart from the transfer position by a predetermined distance. The distance refers to a minimum distance necessary to accelerate the mount <NUM>, which is in the halt state, to a target speed. Actually, the speed of the mount <NUM> needs to be maintained at the target speed. Thus, not only the distance for acceleration but also the distance for checking if the mount <NUM> moves at the target speed is necessary. The target speed is the traveling speed of the intermediate transfer belt <NUM>.

After the mount <NUM>, which starts moving from the end portion in the housing 10A, passes the transfer unit <NUM>, the mount <NUM> is transported to the fixing unit <NUM>. The fixing unit <NUM> fixes the image which has been transferred onto the medium <NUM>. After completion of the fixing, the mount <NUM> is transported to the housing 10C. The medium <NUM>, on which the image has been formed, is taken out through the opening provided for the housing 10C.

The mechanism for implementing a move of the mount <NUM> along the transport rail <NUM> is not particularly limited to this configuration. For example, a configuration in which the leg <NUM> provided with a motor or another driving device moves by itself may be employed. Alternatively, a motor or another driving device which pulls the leg <NUM> may be provided for the transport rail <NUM>.

In addition, the mechanism for raising/lowering the pedestal <NUM> is not limited to this configuration. For example, a configuration in which a rack and pinion and a motor are used to raise/lower the pedestal <NUM> may be provided for the leg <NUM>. A gear or another mechanism which is interlocked with the elevation of the pedestal <NUM> may be provided for the leg <NUM>, and the elevation of the pedestal <NUM> may be adjusted manually.

In height adjustment using a motor or another driving device, information about the height of the mounting surface which is specified by a user may be used, or information about the thickness of a medium <NUM> which is input by a user may be used. Alternatively, a sensor output may be used. The sensor output includes output of a relative height with respect to a reference height, and information such as a pressure and a distortion which are applied to the leg <NUM> when a medium <NUM> is pressed against the intermediate transfer belt <NUM>.

The pedestal <NUM> may be provided, for example, with a groove, a protrusion, or a fastener which is used to position a medium <NUM> or the jig <NUM>. These are exemplary structures or mechanisms for positioning. A combination of these may be provided for the pedestal <NUM>.

For example, when the pedestal <NUM> is provided with a fastener, the jig <NUM> may be fixed to the mounting surface regardless of the shape of the jig <NUM>. The fastener makes an integral unit constituted by the jig <NUM> and the pedestal <NUM>, achieving reduction of transfer misalignment of an image.

In addition, the pedestal <NUM> is mounted so as to be able to rise and fall with respect to the leg <NUM> in accordance with a pressure from above. A mechanism for enabling the pedestal <NUM> to rise and fall is implemented, for example, by disposing a rubber, a spring, or another elastic body in a joint portion between the pedestal <NUM> and the leg <NUM>. Employment of this kind of configuration causes an impact, which occurs when a medium <NUM> comes in contact with the intermediate transfer belt <NUM> of the transfer unit <NUM>, to be softened.

The jig <NUM> is a tool attached to the pedestal <NUM> when necessary. The jig <NUM> has a shape, a structure, and a mechanism in accordance with the structure and the mechanism of the mounting surface of the pedestal <NUM>. For example, a hole for inserting a screw into a tapped hole provided on the mounting surface, a hole for inserting a pin provided on the mounting surface, or a protrusion or a groove for positioning is formed on the bottom surface or a side surface of the jig <NUM>.

A shape, a structure, or a mechanism, which is suitable to hold a medium <NUM> which is an object to be mounted, is provided on the top surface of the jig <NUM>. A jig <NUM> may be prepared for each medium <NUM> which is an object to be mounted, or a jig <NUM> which may support multiple shapes and sizes may be prepared.

The configuration of the fixing unit <NUM> will be described.

In the first exemplary embodiment, both a medium <NUM> before transfer of an image and a medium <NUM> after transfer of an image pass through the fixing unit <NUM>.

The fixing unit <NUM> in the first exemplary embodiment is provided with, not only an operation mode (hereinafter referred to as the "fixing mode") in which a transferred image is fixed on a medium <NUM>, but also an operation mode (hereinafter referred to as the "non-fixing mode") in which a transferred image is passed without being fixed.

<FIG> is a diagram for describing an exemplary configuration of the fixing unit <NUM>. <FIG> illustrates the case in which openings <NUM> and <NUM>, which are doorways of the housing 10B, are open.

The opening <NUM> is opened when a medium <NUM> is taken in/out between the housing 10A and the housing 10B, and is closed when a transferred image is to be fixed onto a medium <NUM>.

The opening <NUM> is opened when a medium <NUM> is taken in/out between the housing 10C and the housing 10B, and is closed when a transferred image is to be fixed onto a medium <NUM>.

In <FIG>, a roll-up shutter <NUM> serving as an opening/closing member is attached to the opening <NUM>. A roll-up shutter <NUM> serving as an opening/closing member is attached to the opening <NUM>. In <FIG>, the openings <NUM> and <NUM> are open. Thus, both the roll-up shutters <NUM> and <NUM> are rolled up. When the openings <NUM> and <NUM> are closed, the end portions of the shutters <NUM> and <NUM> are pulled out to positions near the transport rail <NUM>.

When a medium <NUM> is transported into the fixing unit <NUM> to fix an image, only the shutter <NUM> on the opening <NUM> side is opened, and the shutter <NUM> of the opening <NUM> on the opposite side remains closed. Thus, a decrease of the temperature in the fixing unit <NUM> is reduced. In contrast, when a medium <NUM> having a fixed image is to be taken out, only the shutter <NUM> on the opening <NUM> side is opened, and the shutter <NUM> of the opening <NUM> on the opposite side may remain closed or may be opened.

The fixing unit <NUM> (see <FIG>) in the first exemplary embodiment employs a contactless heating system. Therefore, images may be fixed onto media <NUM> having various thicknesses and shapes.

In <FIG>, a heat source <NUM> is attached to the ceiling of the fixing unit <NUM>. The heat source <NUM> may be attached, not limited to the ceiling, to a wall or both the ceiling and a wall.

For example, a halogen lamp, a ceramic heater, or an infrared lamp is used as the heat source <NUM>. In the first exemplary embodiment, particles melted through heating are fixed onto the surface of a medium <NUM>.

In <FIG>, a roll-up shutter <NUM> is attached between the heat source <NUM> and a space (hereinafter referred to as a "heating chamber") through which a medium <NUM> passes. <FIG> illustrates the state in which the roll-up shutter <NUM> is pulled out, that is, the state in which the heat source <NUM> is separated from the heating chamber. For the shutter <NUM>, a material having the heat insulation property is used.

In <FIG>, the heating chamber contains a temperature sensor <NUM>. The ambient temperature measured by the temperature sensor <NUM> is output to the processing unit <NUM> (see <FIG>).

When the ambient temperature in the heating chamber is greater than or equal to a temperature (hereinafter referred to as a "reference value") at which an image may be fixed, a transferred image is fixed onto a medium <NUM>. In contrast, when the ambient temperature is less than the reference value, a transferred image fails to be fixed onto a medium <NUM>. The reference value is influenced, for example, by the type of transferred particles or the thermal conductivity of a medium <NUM>. In fixing an image, not only the ambient temperature but also the time in which a medium <NUM> stays in the heating chamber is to be considered.

In the first exemplary embodiment, the processing unit <NUM> (see <FIG>) is disposed in the housing 10A (see <FIG>) in which the transfer unit <NUM> (see <FIG>) is disposed. The processing unit <NUM> may be disposed in the housing 10B in which the fixing unit <NUM> (see <FIG>) is disposed, or the housing 10C having the opening through which a medium <NUM> is taken in/out. The processing unit <NUM> may be provided for the housings 10A, 10B, and 10C of the image forming apparatus <NUM> as an external unit, or may be disposed on a network communicatively.

<FIG> is a diagram for describing an exemplary configuration of the processing unit <NUM>.

The processing unit <NUM> includes a processor <NUM>, a read only memory (ROM) <NUM> which stores, for example, a basic input output system (BIOS), a random access memory (RAM) <NUM> which is used as a work area of the processor <NUM>, an auxiliary storage unit <NUM>, a user interface <NUM>, a communication interface <NUM>, and an input/output (I/O) interface <NUM>. The processor <NUM> is connected to the other devices through a bus or another signal line <NUM>.

The processor <NUM> is a device for implementing various functions through execution of programs. The processor <NUM>, the ROM <NUM>, and the RAM <NUM> function as a computer.

The auxiliary storage unit <NUM> is configured, for example, by a hard disk device or a semiconductor storage. The auxiliary storage unit <NUM> stores programs and various types of data. A program herein is used as a general term for an operating system (OS), firmware, and an application program.

In the first exemplary embodiment, the auxiliary storage unit <NUM> is contained in the housing 10A. Alternatively, the auxiliary storage unit <NUM> may be provided, as an external unit, for the housing 10A through the I/O interface <NUM>, or may be a portable memory which may be attached to and detached from the housing 10A. The auxiliary storage unit <NUM> may be present on a network connected to the communication interface <NUM>.

The user interface <NUM> includes, for example, a touch panel, operation buttons, and a speaker which are used in display of an image for operation and in reception of operations. The touch panel is configured by a liquid-crystal display, an organic light-emitting diode (OLED) display, or another display, and an electrostatic-capacity sensor which detects a change in electrostatic capacity.

The communication interface <NUM> is an interface for communicating with terminals on a network. The communication interface <NUM> supports various types of communication standards. The communication standards include, for example, Ethernet™, Wi-Fi™, and a mobile communication system.

The I/O interface <NUM> is an interface for communicating with the transfer unit <NUM> (see <FIG>), the fixing unit <NUM> (see <FIG>), and the transporter <NUM> (see <FIG>).

As described above, media <NUM> have various thicknesses and shapes. Therefore, before images are continuously formed on media <NUM> having the same thickness and shape, an adjustment operation is performed. Specifically, the height of the top of a medium <NUM> is adjusted to the height of the transfer position of the intermediate transfer belt <NUM>.

<FIG> is a diagram for describing an exemplary adjustment operation.

In a height calibration P1, a medium <NUM>, which has been taken in through the opening of the housing 10C, is mounted on the mounting surface of the mount <NUM>. In the example in <FIG>, the jig <NUM> is attached to the top surface of the pedestal <NUM>, and the medium <NUM> is attached to the top surface of the jig <NUM>.

When the medium <NUM> is attached to the jig <NUM>, the height calibration P1 starts. On start of the height calibration P1, the leg <NUM> is lowered from its initial position. The leg <NUM> is lowered in order that, when the mount <NUM> is horizontally moved to the intermediate transfer belt <NUM>, the top of the medium <NUM> does not come in contact with the lower end of the intermediate transfer belt <NUM>. The amount of lowering is predetermined. For example, the mount <NUM> is moved to the lowermost end of the movable range of the leg <NUM>. Hereinafter, the height of the mount <NUM> after the lowering is referred to as the "transport height".

When the mount <NUM> is lowered to the transport height, transporting the mount <NUM> in the horizontal direction starts. The mount <NUM> passes through the fixing unit <NUM>, and is transported to the position where the mount <NUM> faces the intermediate transfer belt <NUM>.

When the mount <NUM> arrives at the target position, transporting the mount <NUM> in the horizontal direction is temporarily stopped.

At this position, the leg <NUM> is raised, and the height (hereinafter also referred to as the "transfer height") at which the top of the medium <NUM> is in contact with the lower end of the intermediate transfer belt <NUM> is detected. This detection operation is referred to as the height calibration P1.

The medium <NUM>, which has been positioned at the transfer height, is pressed against the intermediate transfer belt <NUM> with a strength suitable for transfer.

The transfer height is stored as the height of the leg <NUM> in the RAM <NUM> (see <FIG>) or the auxiliary storage unit <NUM> (see <FIG>) of the processing unit <NUM>.

On completion of the height calibration P1, the leg <NUM> is lowered again to the transport height so that the medium <NUM> is not in contact with the intermediate transfer belt <NUM>. In <FIG>, the raising/lowering operation is indicated by arrow a.

The mount <NUM>, which has been lowered to the transport height, is transported to the preparation position for transfer. In <FIG>, the transport operation is indicated by arrow b.

When the mount <NUM> arrives at the preparation position, transporting the mount <NUM> in the horizontal direction is temporarily stopped.

At this position, the leg <NUM> is raised, and the top of the medium <NUM> is positioned at the transfer height. The positioning operation is referred to as a transfer preparation operation P2. The positioning operation is indicated by arrow a.

When the mount <NUM> is positioned at the transfer height, a transfer operation P3 starts.

On start of the transfer operation P3, the mount <NUM> is transported in the horizontal direction in conjunction with image formation on the intermediate transfer belt <NUM>. In <FIG>, the transport operation is indicated by arrow c.

The images, which have been subjected to first transfer onto the intermediate transfer belt <NUM>, are positioned at the lowermost point of the intermediate transfer belt <NUM> at the time point at which the medium <NUM> has been transported to the transfer position. Therefore, as the medium <NUM> is transported in the horizontal direction, all the images are transferred onto the medium <NUM>.

<FIG> is a diagram for describing an operation performed by the fixing unit <NUM> when an image is to be fixed. In <FIG>, parts corresponding to those in <FIG> are designated with the corresponding reference numerals.

In the first exemplary embodiment, a medium <NUM> is stopped in the heating chamber. The medium <NUM> may continue to move at a low speed in the direction to the housing 10C.

The fixing unit <NUM> raises the ambient temperature in the heating chamber to a reference value or more through heating so that an image is fixed onto the surface of the medium <NUM>. Therefore, the end portion of the shutter <NUM> and that of the shutter <NUM> are lowered to positions near the transport rail <NUM>. As a result, the opening <NUM> and the opening <NUM> are closed. Thus, the ambient temperature in the heating chamber reaches the reference value or more which is suitable for fixing.

<FIG> is a diagram for describing an operation performed by the fixing unit <NUM> when an image is not to be fixed. In <FIG>, parts corresponding to those in <FIG> are designated with the corresponding reference numerals.

For example, when an image is to be formed on a new medium <NUM>, the image quality may be checked by using so-called test printing. However, the per-unit price of a medium <NUM> assumed in the first exemplary embodiment is comparatively expensive. Thus, the following operation mode is prepared for the so-called test printing: an image is transferred onto a medium <NUM>, but the transferred image is not fixed onto the medium <NUM>. That is, the non-fixing mode is prepared.

Therefore, in the non-fixing mode illustrated in <FIG>, the shutter <NUM> and the shutter <NUM> are rolled up, and both the opening <NUM> and the opening <NUM> are open. Since both the opening <NUM> and the opening <NUM> are open, outside air flows into the heating chamber, and, instead, the high-temperature air flows out. Thus, the ambient temperature is decreased. In <FIG>, the shutter <NUM> is pulled out to separate the heat source <NUM> from the heating chamber. Thus, the ambient temperature in the heating chamber is easy to be lower than the reference value. In the case of test printing, control is exerted so that the openings <NUM> and <NUM> are open before an image is transferred onto a medium <NUM>, so that the ambient temperature is lower than the reference value.

In this state, the transporter <NUM> causes the medium <NUM> to pass through the fixing unit <NUM> without stopping. Thus, transferred toner or the like is not fixed onto the surface of the medium <NUM>. As a result, after the image quality of the medium <NUM> taken out from the housing 10C is checked, the transferred toner or the like is removed, enabling reuse of the medium <NUM>.

<FIG> is a flowchart of an exemplary control operation performed by the processor <NUM> (see <FIG>). The symbol, S, illustrated in <FIG> means a step.

The processor <NUM>, which has started running a program, determines whether a user has instructed that the non-fixing mode is to be used (step <NUM>).

The "non-fixing mode" may be accepted as "printing without fixing an image" which is literally meant, or may be accepted as "test printing". Printing with fixing an image is handled as the "fixing mode" even if it is literally "test printing".

If a positive result is obtained in step <NUM>, the processor <NUM> sets the operation mode to the non-fixing mode (step <NUM>). If the non-fixing mode is set, the processor <NUM> maintains the open state of the opening <NUM> and the opening <NUM> of the fixing unit <NUM> even after start of the height calibration P1. In addition, the processor <NUM> pulls out the shutter <NUM> to stop heating the heating chamber by the heat source <NUM>.

The processor <NUM> transfers an image onto a medium <NUM> (step <NUM>).

After that, the processor <NUM> determines whether the temperature in the fixing unit <NUM> is greater than or equal to the reference value (step <NUM>). The temperature is the ambient temperature in the heating chamber which is measured by the temperature sensor <NUM> (see <FIG>).

If a positive result is obtained in step <NUM>, the processor <NUM> temporarily stops taking the medium, onto which the image has been transferred, into the fixing unit <NUM> (step <NUM>). After that, the processor <NUM> returns to the determination in step <NUM>. While a positive result is obtained in step <NUM>, the processor <NUM> repeatedly performs the processes in step <NUM> and step <NUM>.

When the temperature in the fixing unit <NUM> is lower than the reference value, a negative result is obtained in step <NUM>. When a negative result is obtained in step <NUM>, the processor <NUM> transports the medium, onto which the image has been transferred, to the discharge position without stopping the medium in the fixing unit <NUM> (step <NUM>). In this case, since the temperature in the fixing unit <NUM> is less than the reference value and the medium <NUM> passes through the fixing unit <NUM> without stopping in the fixing unit <NUM>, the image, which has been transferred onto the surface of the medium <NUM>, is not fixed.

If a negative result is obtained in step <NUM>, the processor <NUM> determines whether a user instructs that the medium <NUM> is to be changed (step <NUM>).

Even when the user specifies the fixing mode, if the user instructs that the thickness or shape of the medium <NUM> is to be changed, the height calibration and the like are highly likely to be necessary.

Therefore, in the first exemplary embodiment, if a positive result is obtained in step <NUM>, the processor <NUM> sets the operation mode to the non-fixing mode (step <NUM>). After that, steps <NUM> to <NUM> are performed.

In contrast, if a negative result is obtained in step <NUM>, the processor <NUM> sets the operation mode to the fixing mode (step <NUM>).

Then, the processor <NUM> transfers an image onto the medium <NUM> (step <NUM>).

After that, the processor <NUM> takes the medium, onto which the image has been transferred, into the fixing unit <NUM> for heating (step <NUM>). Since it is in the fixing mode, the temperature in the heating chamber is greater than or equal to the reference value. Therefore, the image is fixed onto the surface of the medium <NUM>.

After that, the processor <NUM> transports the medium <NUM>, on which the image has been fixed, to the discharge position (step <NUM>).

In a second exemplary embodiment, the case in which an infrared laser or an ultraviolet laser is used to fix an image will be described.

<FIG> is a diagram for describing a schematic configuration of a fixing unit 200A used in the image forming apparatus <NUM> assumed in the second exemplary embodiment. In <FIG>, parts corresponding to those in <FIG> are designated with the corresponding reference numerals.

The fixing unit 200A in <FIG> includes a laser source 210A which emits laser light for melting particles transferred onto a medium <NUM>.

In the case of use of the laser source 210A, a local portion of the surface of a medium <NUM> is heated. Thus, the shutters <NUM>, <NUM>, and <NUM> are not provided. In addition, the temperature sensor <NUM> is also unnecessary.

In the second exemplary embodiment, the laser source 210A emits laser light in the fixing mode, and a local portion of the surface of the medium <NUM> taken into the fixing unit 200A is heated. Toner or the like melted through heating causes the image to be fixed on the surface of the medium <NUM>.

In contrast, in the non-fixing mode, emission of laser light by the laser source 210A is stopped. Therefore, even when a medium <NUM>, onto which an image has been transferred, passes through the fixing unit 200A, the image is not fixed on the medium <NUM>.

In a third exemplary embodiment, the case in which an image is fixed through contact with a medium <NUM> will be described.

<FIG> are diagrams for describing a schematic configuration of a fixing unit 200B used in the image forming apparatus <NUM> assumed in the third exemplary embodiment. In <FIG>, parts corresponding to those in <FIG> are designated with the corresponding reference numerals.

The fixing unit 200B in <FIG> includes a fixing roller 210B which applies a pressure or heat to toner or the like transferred onto a medium <NUM> for melting.

<FIG> is a diagram illustrating the mode M1 for describing the position of the fixing roller 210B in the fixing mode. In the fixing mode, the fixing roller 210B is lowered to the height at which the fixing roller 210B is in contact with the surface of a medium <NUM> which moves in the horizontal direction.

<FIG> is a diagram illustrating the mode M2 for describing the position of the fixing roller 210B in the non-fixing mode. In the non-fixing mode, the fixing roller 210B is raised to a height at which the fixing roller 210B is not in contact with the surface of a medium <NUM> which moves in the horizontal direction. That is, the fixing roller 210B is evacuated from the transport path.

Claim 1:
An image forming system (<NUM>), comprising:
a transporter (<NUM>) that transports an object (<NUM>);
a transfer unit (<NUM>) that transfers an image onto the object (<NUM>) transported by the transporter (<NUM>);
a fixing unit (<NUM>) that fixes, onto the object (<NUM>), the image transferred by the transfer unit (<NUM>); and
a processor (<NUM>) configured to:
in a first mode, exert control to transfer the image onto the object (<NUM>) such that the image is fixed onto the object (<NUM>) by the fixing unit (<NUM>);
in a second mode, exert control to transfer the image onto the object (<NUM>) such that the image is not fixed onto the object (<NUM>) by the fixing unit (<NUM>),
characterized in that
the processor (<NUM>) is further configured to:
when an instruction to change the object (<NUM>) so as to transfer the image onto another object, wherein the thickness or the shape is changed, is received through an operation unit (<NUM>), make a transition to the second mode.