Image forming apparatus

Abstract

To allow, in printing on a medium having a circumferential surface, printing an image on the circumferential surface along a circumference compared with a case where the medium is fixed to and conveyed by conveying means for the printing.SOLUTION: An image forming apparatus comprises: a transfer unit 100 that is brought into contact with a medium 500 to transfer an image to the medium 500; a jig that holds the medium 500 having a circumferential surface so that the circumferential surface rotates along a transfer direction of the transfer unit 100; and a conveying mechanism 400 that conveys the jig holding the medium 500 along a conveyance path. The transfer unit 100 is brought into contact with the circumferential surface of the medium 500 maintained at a transfer position, and transfers the image to the circumferential surface of the medium 500 in a circumferential direction accompanying the rotation of the medium 500.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] In recent years, there has been a case of printing an image on a medium having various thicknesses and shapes such as metal, glass, and tile as an object.

[0003] Patent Document 1 discloses a printing apparatus that places a disk on a conveyance table and forms an image on the disk while conveying the disk together with the conveyance table.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a printing method in which an image is transferred by bringing a transfer unit into contact with an object, it has been difficult to transfer an image along the circumference of a circumferential surface such as a cylinder or a sphere.

[0006] An object of the present invention is to enable printing an image along the circumference of a circumferential surface in printing on a medium having a circumferential surface, as compared with a configuration in which the medium is fixed to a conveyance means and conveyed and printed.

Means for Solving the Problems

[0007] The present invention according to claim 1 is A transfer unit that comes into contact with an object and transfers an image onto the object, A holding unit that holds the object having a circumferential surface such that the circumferential surface rotates along the transfer direction of the transfer unit, The system comprises a transport unit that transports the holding unit holding the object along a transport path, The transfer unit contacts the circumferential surface of the object maintained in the transfer position, and as the object rotates, transfers an image to the circumferential surface of the object in the circumferential direction. The holding unit includes a movable base unit that moves along the transport path by the transport unit, A support portion is provided on the movable base portion so as to be movable in the opposite direction to the transport direction by the transport portion, and rotatably supports the object, This is an image forming apparatus characterized by further comprising the following features. Claim 2 The present invention relating to this invention is The holding portion is further characterized by comprising a drive mechanism that moves the support portion relative to the movable base portion in the opposite direction to the transport direction by the transport portion and at the same speed as the transport speed by the transport portion, as per the claim. 1 This is the image forming apparatus described in [reference]. The present invention according to claim 3 is A transfer unit that comes into contact with an object and transfers an image onto the object, A holding unit that holds the object having a circumferential surface such that the circumferential surface rotates along the transfer direction of the transfer unit, The system comprises a transport unit that transports the holding unit holding the object along a transport path, The transfer unit contacts the circumferential surface of the object maintained in the transfer position, and as the object rotates, transfers an image to the circumferential surface of the object in the circumferential direction. The holding part includes a support base that supports the object in the state in which it is placed, The support base is provided with a roller that has a rotation axis substantially perpendicular to the conveying direction of the conveying unit and supports the circumferential surface of the object, The roller of the support base is provided to support the object in an area other than the image area on which the image of the object is transferred, It is an image forming apparatus. Claim 4 The present invention relating to this invention is The support base is characterized by comprising a driving means for rotating the roller so that the object rotates at a speed corresponding to the image transfer speed by the transfer unit, claim 3 This is the image forming apparatus described in [reference]. Claim 5 The present invention relating to this invention is The image forming apparatus according to claim 1, characterized in that the holding portion includes a pivot portion that supports the object with the central axis of the circumferential surface containing the image region on which the image is transferred as the axis of rotation. Claim 6 The present invention relating to this invention is The claim is characterized by comprising a driving means for driving the rotation axis so that the object rotates at a speed corresponding to the image transfer speed by the transfer unit. 5 This is the image forming apparatus described in [reference]. [Effects of the Invention]

[0008] According to the invention of claim 1, compared with the configuration of fixing a medium to a conveying means and conveying and printing it, an image can be printed along the circumference with respect to the circumferential surface. Claim 2 According to the invention, compared with the configuration without using a driving means, an object can be stably held at a transfer position. Claim 3 According to the invention, unlike the configuration in which a roller is provided at a position corresponding to an image area, an image can be transferred over the entire circumferential surface of an object. Claim 4 According to the invention, compared with the configuration of rotationally driving an object passively according to the operation of a transfer unit, an image can be transferred by stably rotating the object regardless of the material of the object. Claim 5 According to the invention, compared with the configuration of fixing a medium to a conveying means, by setting a rotation axis, an object can be rotated to transfer an image onto a circumferential surface. Claim 6 According to the invention, compared with the configuration of rotationally driving an object passively according to the operation of a transfer unit, an image can be transferred by stably rotating the object regardless of the material of the object.

Brief Description of Drawings

[0009] [Figure 1] It is a diagram showing the configuration of an image forming apparatus to which this embodiment is applied. [Figure 2] It is a diagram showing the configuration of a transfer unit. [Figure 3] It is a diagram showing the operation of a conveying mechanism before image formation by a transfer unit is started. FIG. 3(A) is a diagram showing a state of performing height control, FIG. 3(B) is a diagram showing a state of retreating to a preparation position after height control, and FIG. 3(C) is a diagram showing a state where image transfer by a transfer unit is started. [Figure 4] It is a diagram showing the configuration and operation of a fixing unit. FIG. 4(A) is a diagram showing a state where an opening of the fixing unit is closed, and FIG. 4(B) is a diagram showing a state where the opening of the fixing unit is open. [Figure 5]This diagram illustrates a method for transferring an image to a medium having a circumferential surface. Figure 5(A) shows the state at the start of the transfer, Figure 5(B) shows the state during the transfer, and Figure 5(C) shows the state at the end of the transfer. [Figure 6] This figure shows an example of the configuration of a jig for rotatably holding a medium. Figure 6(A) shows the jig and medium viewed in a direction parallel to the medium's axis of rotation, and Figure 6(B) shows the relationship between the medium and the rollers of the jig in a direction perpendicular to the medium's axis of rotation. [Figure 7] Figure 7(A) shows another example configuration of a jig for rotatably holding a medium, with the jig and medium viewed parallel to the axis of rotation of the medium, and Figure 7(B) showing the jig and medium viewed perpendicular to the axis of rotation of the medium. [Figure 8] These figures illustrate examples of media with a circumferential surface; Figure 8(A) shows a spherical media, and Figure 8(B) shows a frustoconical media. [Figure 9] These diagrams show the movement of the jig. Figure 9(A) shows the state at the start of the transfer, Figure 9(B) shows the state during the transfer, and Figure 9(C) shows the state at the end of the transfer. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the attached drawings. The image forming apparatus of this embodiment is an image forming apparatus that uses digital printing. Digital printing methods include electrophotography and inkjet, but in this embodiment, the electrophotography method is assumed. In the electrophotography method, the transfer unit and the medium come into contact when an image is transferred to the medium. In this embodiment, the object to be printed is assumed to be a medium having various thicknesses and shapes, such as metal, glass, and tiles.

[0011] <Device configuration> Figure 1 shows the configuration of an image forming apparatus to which this embodiment is applied. The image forming apparatus 10 comprises a transfer unit 100, a fixing unit 200, a media attachment / detachment unit 300, and a transport mechanism 400. Although not specifically shown, the image forming apparatus 10 also comprises a control unit having one or more processors as computing means, memory as a work area for data processing, and a storage device for holding programs and data. The control unit may be a single unit that controls the operation of the entire image forming apparatus 10, or it may be provided individually for each of the transfer unit 100, fixing unit 200, transport mechanism 400, etc.

[0012] The transfer unit 100 is a unit that transfers an image formed from particles such as toner onto the medium 500. The fixing unit 200 is a unit that fixes the image transferred by the transfer unit 100 to the surface of the medium 500 by heating the medium 500. The medium attachment / detachment unit 300 is a unit in which the user of the image forming apparatus 10 attaches the medium 500 to a mounting base (described later) provided on the transport mechanism 400. The transport mechanism 400 is provided throughout the transfer unit 100, the fixing unit 200, and the medium attachment / detachment unit 300, and transports the medium 500 to be printed to each unit 100, 200, and 300 as shown by the arrows in Figure 1.

[0013] The media loading / unloading section 300 is a housing that has an opening in part of it through which the media 500 can be loaded and unloaded. As will be described in more detail later, the inside of the media loading / unloading section 300 contains a portion of the transport rail 410 that constitutes the transport mechanism 400, and the transport start position and transport end position are set there. In this embodiment, the transport start position and the transport end position are set to the same location. In the initial state, the mounting base 420 that constitutes the transport mechanism 400 is placed at the location of the transport rail 410 that is set as the transport start position and the transport end position. When the user inserts the jig 423 holding the media 500 through the opening of the housing of the media loading / unloading section 300 and attaches it to the mounting base 420, the transport mechanism 400 becomes capable of transporting the media 500. After the image is transferred to the media 500 by the transfer section 100 and the fixing process is performed by the fixing section 200, the mounting base 420 on which the media 500 is placed moves along the transport rail 410 to reach the transport end position. In this state, the user removes the jig 423 holding the media 500 from the mounting base 420 and takes it out through the opening in the housing of the media attachment / detachment section 300.

[0014] <Configuration of the transfer unit 100> Figure 2 shows the configuration of the transfer unit 100. The transfer unit 100 forms an image with charged particles and generates an electric field to transfer the image to the medium 500. The transfer unit 100 comprises a developing device 110, a primary transfer roll 120, and an intermediate transfer belt 131. The intermediate transfer belt 131 is stretched between the developing device 110 and the position where the transfer to the medium 500 takes place, by rollers 132, 133 and a backup roll 140. The transfer unit 100 also includes a cleaning device 150 for removing particles adhering to the intermediate transfer belt 131.

[0015] The developing unit 110 is a unit that forms an electrostatic latent image of the image to be transferred onto a photoreceptor and develops the image by attaching charged particles to this electrostatic latent image on the photoreceptor. Existing devices used in electrophotographic image forming apparatuses can be used as the developing unit 110. Figure 2 shows an example configuration for color image forming processing using four colors: yellow, magenta, cyan, and black. A separate developing unit 110 is provided for each of these colors, and in Figure 2, the developing units 110 for yellow, magenta, cyan, and black are indicated with the subscripts Y, M, C, and K, respectively, to represent the corresponding color. In the following description, when distinguishing between the colors in relation to the developing unit 110, the subscripts Y, M, C, and K are added to the symbols; however, when it is not necessary to distinguish between the colors, the subscripts are omitted.

[0016] The primary transfer roll 120 is a unit used to transfer (primary transfer) the image formed in the developing unit 110 to the intermediate transfer belt 131. The primary transfer roll 120 is positioned opposite the photoreceptor of the developing unit 110, and the intermediate transfer belt 131 is positioned between the developing unit 110 and the primary transfer roll 120. The primary transfer roll 120 is provided in correspondence to each of the developing units 110Y, 110M, 110C, and 110K. In Figure 2, each primary transfer roll 120 corresponding to the developing unit 110Y, 110M, 110C, and 110K for each color is indicated with the subscripts Y, M, C, and K to indicate the corresponding color. In the following description, when distinguishing each color with respect to the primary transfer roll 120, the subscripts Y, M, C, and K are added to the symbols, but when it is not necessary to distinguish each color, the subscripts are omitted.

[0017] The intermediate transfer belt 131, rollers 132 and 133, and backup roll 140 are units used to transfer the image formed in the developing apparatus 110 to the medium 500. As shown in Figure 2, the intermediate transfer belt 131 is stretched over the rollers 132 and 133 and the backup roll 140 and rotates in the direction of the arrow in Figure 2 (counterclockwise in the illustrated example). The rotation of the intermediate transfer belt 131 is achieved, for example, by using a roller that rotates one or both of the rollers 132 and 133, and pulling the intermediate transfer belt 131 with the rotation of this roller.

[0018] In the configuration example shown in Figure 2, the outer surface of the intermediate transfer belt 131 is the surface that holds the image (hereinafter referred to as the "transfer surface"). As the intermediate transfer belt 131 passes between the developing device 110 and the primary transfer roll 120, the image is transferred from the photoreceptor of the developing device 110 to the transfer surface of the intermediate transfer belt 131. In the configuration example shown in Figure 2, a multicolor image is formed by superimposing images of yellow (Y), magenta (M), cyan (C), and black (K) onto the transfer surface using the developing devices 110Y, 110M, 110C, 110K and the primary transfer rolls 120Y, 120M, 120C, 120K.

[0019] The backup roll 140 brings the transfer surface of the intermediate transfer belt 131 into contact with the medium 500, transferring the image to the medium (secondary transfer). When transferring the image, a predetermined voltage is applied to the backup roll 140. This generates an electric field (hereinafter referred to as the "transfer electric field") in the area including the backup roll 140 and the medium 500, and the image formed by the charged particles is transferred from the intermediate transfer belt 131 to the medium 500. In this way, in order to transfer the image from the intermediate transfer belt 131 to the medium 500, current must flow from the backup roll 140 through the intermediate transfer belt 131 to the medium 500. If the medium 500 is a conductor such as a metal, current flows through the medium 500 itself, generating a transfer electric field and transferring the image to the surface of the medium 500. On the other hand, if the medium 500 is not a conductor, current does not flow through the medium, and therefore the image cannot be transferred as is. Therefore, when a non-conductor material is used as the medium 500, measures are taken beforehand to allow current to flow through the medium 500, such as forming a layer of conductive material (hereinafter referred to as the "conductive layer") in at least the region on the surface of the medium 500 where the image is to be formed.

[0020] The procedure for transferring an image using the intermediate transfer belt 131 will now be described. As the intermediate transfer belt 131 rotates, the developing devices 110Y, 110M, 110C, 110K and the primary transfer rolls 120Y, 120M, 120C, 120K sequentially superimpose images of yellow (Y), magenta (M), cyan (C), and black (K) onto the transfer surface of the intermediate transfer belt 131 (the outer surface in Figure 2), forming a multicolor image. As the intermediate transfer belt 131 rotates further, the image formed on the transfer surface of the intermediate transfer belt 131 reaches the position where the intermediate transfer belt 131 contacts the medium 500 (hereinafter referred to as the "transfer position"). At this point, as described above, a voltage is applied to the backup roll 140 to generate a transfer electric field, and the image is transferred from the intermediate transfer belt 131 to the medium 500. Furthermore, the direction of travel of the intermediate transfer belt 131 at the transfer position is parallel to the transport direction of the mounting base 420 by the transport mechanism 400, and coincides with the transport direction when the image is transferred to the medium 500.

[0021] The cleaning device 150 is a unit that removes particles adhering to the transfer surface of the intermediate transfer belt 131. The cleaning device 150 is located downstream of the transfer position in the rotational direction of the intermediate transfer belt 131 and upstream of the developing device 110Y and the primary transfer roll 120Y. As a result, after the image is transferred from the intermediate transfer belt 131 to the medium 500, any particles remaining on the transfer surface of the intermediate transfer belt 131 are removed by the cleaning device 150. Then, in the next operation cycle, a new image is transferred (primary transfer) to the transfer surface from which the particles have been removed.

[0022] <Configuration of the transport mechanism 400 and mounting structure of the media 500> Here, the mounting structure for the medium 500 will be described. In this embodiment, we assume that the medium 500 has various thicknesses and shapes. When the medium 500 is directly placed on a transport path composed of belts and rollers and transported, if the thickness and shape of the medium 500 differ, the height of the medium 500 relative to the transport path will differ at the transfer position of the transfer section 100, making it difficult to properly bring the intermediate transfer belt 131 into contact with the medium 500. Specifically, if the height of the medium 500 is low, the medium 500 will not contact the intermediate transfer belt 131, and if the height of the medium 500 is high, a strong impact may occur when the medium 500 contacts the intermediate transfer belt 131. Therefore, in this embodiment, the transport mechanism 400 places the medium 500 on a mounting base 420 equipped with height control means, and transports the medium 500 together with this mounting base 420.

[0023] Referring to Figure 2, the transport mechanism 400 includes a transport rail 410 that specifies the transport path for the medium 500, and a mounting base 420 that moves along the transport rail 410. The mounting base 420 includes legs 421 attached to the transport rail 410 and a base 422 for placing the medium 500 on. A jig 423 for holding the medium 500 on the base 422 is attached to the base 422. The transport mechanism 400 is an example of a transport unit. The mounting base 420 is an example of a holding unit.

[0024] In the configuration example shown in Figure 1, the transport rail 410 is installed from the media attachment / detachment section 300 through the fixing section 200 to the transfer section 100. The end of the transport rail 410 on the media attachment / detachment section 300 side is the transport start position and the transport end position. The mounting base 420 is transported from the transport start position of the media attachment / detachment section 300 to the left in Figure 1, and the image is transferred to the media 500 in the transfer section 100. After the image transfer, the mounting base 420 is transported to the right in Figure 1, and after the image is fixed to the media 500 in the fixing section 200, it reaches the transport end position of the media attachment / detachment section 300.

[0025] The leg portion 421 is attached to the transport rail 410 and moves along the transport rail 410. The mechanism for the leg portion 421 to move along the transport rail 410 is not particularly limited. For example, the leg portion 421 may be equipped with a drive device to allow it to move on its own, or the transport rail 410 may be equipped with a means for pulling the leg portion 421. The leg portion 421 also has a height control means for controlling the height of the base portion 422. The configuration of the height control means is not particularly limited. For example, it may be configured to raise and lower the base portion 422 using a rack and pinion and a drive motor. Alternatively, it may be configured to control the height of the base portion 422 by manually operating a gear that is linked to the height of the base portion 422. Furthermore, various methods can be used for operating the height control. For example, an input interface to the control unit of the drive motor may be provided, and the operator of the image forming apparatus 10 may manually input and set the height data using the input interface. Alternatively, a sensor may be used to automatically detect the height of the medium 500 mounted on the mounting base 420, and the drive motor may be controlled so that the medium 500 is at an appropriate height.

[0026] The base portion 422 is attached to the leg portion 421 and is a platform on which the medium 500 is placed via the jig 423. The base portion 422 is provided with fasteners (not shown) for positioning the jig 423. Any jig 423 that fits these fasteners can be positioned and attached to the base portion 422 regardless of the shape of the jig 423 itself. The leg portion 421 and the base portion 422 are examples of a movable base portion.

[0027] Furthermore, the base portion 422 is mounted so as to rise and fall relative to the leg portion 421 in response to pressure from above. The rising and falling of the base portion 422 is achieved, for example, by interposing an elastic body at the joint between the base portion 422 and the leg portion 421. With this configuration, the impact when the medium 500 held by the jig 423 attached to the base portion 422 comes into contact with the intermediate transfer belt 131 of the transfer portion 100 is mitigated.

[0028] The jig 423 is a device that holds the medium 500 and is attached to the base portion 422. The part of the jig 423 that is attached to the base portion 422 has a shape and structure that fits the fasteners of the base portion 422. The jig 423 also has a shape for holding the medium 500. Therefore, by preparing a jig 423 according to the shape and size of the medium 500, various shapes and sizes of medium 500 can be placed on the mounting base 420. In this embodiment, the medium 500 that is the target of image formation is assumed to be a medium 500 having a circumferential surface, and the transfer portion 100 transfers the image to the circumferential surface of the medium 500 along the circumferential direction. For this reason, the jig 423 used has the function of bringing the circumferential surface of the medium 500 into contact with the intermediate transfer belt 131 of the transfer portion 100 along the circumferential direction. Details of such a jig 423 will be described later. The jig 423 is an example of a support portion, support base, and pivot support portion.

[0029] <Pre-processing for image formation> The image forming apparatus 10 of this embodiment has a transport mechanism 400 configured as described above, and can therefore print on media 500 of various shapes and sizes. However, in order to prevent problems such as strong impacts occurring due to contact between the media 500 and the intermediate transfer belt 131 of the transfer unit 100, or failure to make contact, when transferring an image to the media 500, the height of the base unit 422 is controlled before the image transfer operation begins.

[0030] Figure 3 shows the operation of the transport mechanism 400 before image formation by the transfer unit 100 begins. Figure 3(A) shows the height control process, Figure 3(B) shows the mechanism retracted to the preparation position after height control, and Figure 3(C) shows the state when image transfer by the transfer unit 100 begins.

[0031] When image formation is performed on the medium 500, first, at the transport start position of the medium attachment / detachment unit 300, the medium 500 held by the jig 423 is set on the mounting base 420. Then, the height control means of the mounting base 420 lowers the medium 500 to a height where it does not come into contact with the intermediate transfer belt 131 of the transfer unit 100, and then the mounting base 420 with the medium 500 on it moves to below the transfer position of the transfer unit 100.

[0032] Next, the height of the mounting base 420 is controlled so that the medium 500 contacts the intermediate transfer belt 131 with an appropriate strength for transferring the image at the transfer position (arrow a in Figure 3(A)). Once the height control is performed, the information of the obtained appropriate height (hereinafter referred to as the "transfer execution height") is stored in the memory of the control unit. Then, the mounting base 420 is lowered to a height where the medium 500 does not contact the intermediate transfer belt 131 and moves to the preparation position for the transfer operation (arrow b in Figure 3(A)).

[0033] When the mounting base 420 moves to the preparation position, the height of the mounting base 420 is adjusted to the transfer execution height based on the information obtained from the height control. After this, the mounting base 420 moves to the transfer position (arrow c in Figure 3(B)), and when the medium 500 comes into contact with the intermediate transfer belt 131 at the transfer position, the transfer of the image begins (Figure 3(C)).

[0034] <Configuration of the fixing unit 200> Once the image is transferred to the medium 500 in the transfer unit 100, the image is then fixed in the fixing unit 200. In this embodiment, since images are formed on mediums 500 of various thicknesses and shapes, a non-contact fixing process is performed. The fixing unit 200 heats and melts the particles that form the image transferred to the medium 500 and fixes them to the surface of the medium 500.

[0035] Figure 4 shows the configuration and operation of the fixing unit 200. Figure 4(A) shows the fixing unit 200 with its opening closed, and Figure 4(B) shows the fixing unit 200 with its opening open. The fixing unit 200 includes an inlet 201 for loading the medium 500 and an outlet 202 for unloading the medium 500. In addition, the inlet 201 and outlet 202 of the fixing unit 200 in this embodiment are provided with opening and closing members, which are configured to open when loading and unloading the medium 500 and to close when performing the fixing process.

[0036] Here, the opening into which the medium 500 is brought in when the image fixing process is performed by the fixing unit 200 is designated as the inlet 201, and the opening out on the side from which the medium 500 is discharged is designated as the outlet 202. In other words, the opening on the side facing the transfer unit 100 is designated as the inlet 201, and the opening on the side facing the medium attachment / detachment unit 300 is designated as the outlet 202. In the example shown in Figures 4(A) and (B), the opening on the left is the inlet 201, and the opening on the right is the outlet 202. In this embodiment of the image forming apparatus 10, when the medium 500 is transported from the transport start position of the medium attachment / detachment unit 300 to the transfer unit 100, the medium 500 passes through the fixing unit 200. At this time, the medium 500 enters the fixing unit 200 from the outlet 202 and exits from the inlet 201, the opposite of when the fixing process is performed. However, in this embodiment, the inlet 201 and outlet 202 were set as described above based on the operation when the fixing process is performed in the fixing unit 200.

[0037] The fixing unit 200 is equipped with a heat source 210 for heat fixing. Various existing heat sources such as halogen lamps, ceramic heaters, and infrared lamps can be used as the heat source 210. Alternatively, instead of the heat source 210, a device that heats the particles forming the image by irradiating them with an infrared laser may be used. The fixing unit 200 in this embodiment is provided with a covering member that can cover the heat source 210, and is configured to expose the heat source 210 when performing the fixing process.

[0038] In the example shown in Figures 4(A) and (B), retractable shutters 220 and 230 are provided as opening and closing members for the loading entrance 201 and the loading exit 202. The shutters 220 and 230 are kept closed except when loading or unloading the medium 500 (see Figure 4(A)) to prevent the internal temperature from dropping. When loading the medium 500, the shutter 220 of the loading entrance 201 opens, and when unloading the medium 500, the shutter 230 of the loading exit 202 opens (see Figure 4(B)).

[0039] Furthermore, in the examples shown in Figures 4(A) and (B), a retractable shutter 240 is provided as a covering member to cover the heat source 210. The shutter 240 closes when the shutters 220 and 230 of the entrance 201 and exit 202 are opened (see Figure 4(B)). This makes it possible to suppress the temperature drop of the heat source 210 even when the temperature inside drops due to the opening of the entrance 201 and exit 202.

[0040] In the example shown in Figure 4(B), both the shutter 220 of the loading entrance 201 and the shutter 230 of the loading exit 202 are shown open, but this is for the sake of explanation. In actual operation, the shutter 230 of the loading exit 202 is kept closed when loading the media 500, and the shutter 220 of the loading entrance 201 is kept closed when loading the media 500. This prevents the internal temperature from dropping.

[0041] The shutters 220, 230, and 240 shown in Figures 4(A) and (B) are examples of opening and closing members for the loading entrance 201 and loading exit 202, and covering members for the heat source 210. These opening and closing members and covering members only need to suppress the decrease in temperature inside the fixing section 200 and the heat source 210, and are not limited to the above configuration. For example, instead of the shutters 220, 230, and 240 shown in Figures 4(A) and (B), opening and closing doors may be provided. Also, as the opening and closing member for the loading exit 202 through which the medium 500 passes after the fixing process is complete, a curtain or air curtain made of insulating material may be used to prevent the leakage of internal air.

[0042] <Transferring an image onto a medium 500 having a circumferential surface> Figure 5 shows a method for transferring an image to a medium 500 having a circumferential surface. Figure 5(A) shows the state at the start of the transfer, Figure 5(B) shows the state during the transfer, and Figure 5(C) shows the state at the end of the transfer. In the example shown in Figure 5, an image T is transferred to the side surface of a cylindrical medium 500 over half of its circumference.

[0043] To form an image T along the circumferential direction on the circumferential surface of the medium 500, it is necessary to stop the medium 500 at the transfer position of the transfer unit 100 and move the portion of the side surface of the medium 500 that contacts the intermediate transfer belt 131 of the transfer unit 100 in accordance with the progress of the intermediate transfer belt 131. For this reason, the jig 423 holds the medium 500 so that the central axis of the circumferential surface of the medium 500 is perpendicular to the direction of progress of the intermediate transfer belt 131 at the transfer position (hereinafter referred to as the "transfer direction"), and rotates the medium 500 around its central axis. The direction of rotation of the medium 500 is such that, at the position where the intermediate transfer belt 131 and the circumferential surface of the medium 500 come into contact, the progress of the circumferential surface coincides with the transfer direction of the intermediate transfer belt 131. In the examples shown in Figures 5(A) to (C), the medium 500 is shown with the central axis of the circumferential surface perpendicular to the plane of the paper. Then, the intermediate transfer belt 131 moves from left to right in the diagram, and the medium 500 rotates clockwise in the diagram (see arrow in the diagram).

[0044] When the transfer unit 100 transfers an image T to the medium 500, first, as the intermediate transfer belt 131 advances, the developing device 110 for each color forms an image T on the intermediate transfer belt 131. Then, as the intermediate transfer belt 131 advances further and the image T formed on the intermediate transfer belt 131 reaches the transfer position, the image T is transferred from the intermediate transfer belt 131 to the medium 500, as shown in Figure 5(A). As the intermediate transfer belt 131 advances further, the medium 500 rotates, and the transfer of the image T is performed as the contact area of ​​the medium 500 moves along the circumferential direction. As a result, as shown in Figures 5(B) and (C), the image T on the intermediate transfer belt 131 is transferred to the circumferential surface of the medium 500 along the circumferential direction.

[0045] <Configuration of jig 423> Next, a jig 423 for the medium 500 having a circumferential surface will be described. In this embodiment, as described with reference to Figure 5, a jig 423 is used that rotates the medium 500 and brings the circumferential surface of the medium 500 into continuous contact with the intermediate transfer belt 131 of the transfer unit 100 along the circumferential direction. The configuration of such a jig 423 will be described below with specific examples.

[0046] Figure 6 shows an example configuration of a jig 423 that rotatably holds the medium 500. Figure 6(A) shows the jig 423 and the medium 500 viewed in a direction parallel to the rotation axis of the medium 500, and Figure 6(B) shows the relationship between the medium 500 and the roller 423b of the jig 423 in a direction perpendicular to the rotation axis of the medium 500. Note that only the medium 500 and the roller 423b are shown in Figure 6(B). The jig 423 shown in Figure 6(A) comprises a base 423a and a roller 423b. The base 423a has a built-in drive device 423c for rotating the roller 423b. In the jig 423 shown in Figure 6(A), the base 423a has a structure that fits the fasteners of the base portion 422 and is fixed to the base portion 422.

[0047] The roller 423b contacts the circumferential surface of the medium 500 and supports the medium 500 so that it can rotate. The roller 423b is positioned on the base 423a such that its axis of rotation is perpendicular to the transfer direction of the intermediate transfer belt 131, and the medium 500 can be placed on the roller 423b. In the example shown in Figure 6(A), two rollers 423b are positioned with their axes of rotation parallel and at an appropriate distance apart, and the medium 500 is placed between these two rollers 423b. Although it appears that two rollers 423b are positioned in Figure 6(A), two rollers 423b are positioned on each of the two axes of rotation, as shown in Figure 6(B). A material such as rubber with a high coefficient of friction is used on the rotating surface of each roller 423b.

[0048] As described with reference to Figure 5, the image forming apparatus 10 of this embodiment rotates the medium 500 at the transfer position when forming an image on the medium 500. As a result, the portion of the circumferential surface of the medium 500 to which the image has been transferred may move downward as the medium 500 rotates and reach a position corresponding to the roller 423b. For example, this may occur when the image is transferred over half or the entire circumference of the circumferential surface of the medium 500. In such cases, it is necessary to avoid contact between the image transferred to the circumferential surface of the medium 500 and the roller 423b. For this reason, the roller 423b is configured to support the medium 500 in areas other than the region on the circumferential surface of the medium 500 where the image has been transferred.

[0049] In the example shown in Figure 6(B), an image transfer region R is set on the circumferential surface of the medium 500, near the center in the direction of the central axis. Two rollers 423b, whose rotation axes are aligned, are positioned on both sides of region R, supporting the medium 500 without touching region R. Note that the configuration shown in Figure 6(B) is just one example of a configuration in which the rollers 423b do not come into contact with region R on the medium 500, and the shape of the rollers 423b is not limited to the illustrated configuration. For example, instead of arranging multiple rollers 423b as shown in Figure 6(B), rollers 423b could be used in which the part corresponding to region R is formed to be thinner than the parts on either side, so as not to touch region R.

[0050] The drive unit 423c is a driving means for rotating the roller 423b. The roller 423b rotates by obtaining power from the drive unit 423c, thereby rotating the medium 500. Various existing mechanisms can be used as the drive unit 423c, and the specific structure is not limited. For example, a motor and a drive roller that rotates by obtaining power from the motor may be used, and the rotation of the drive roller may be transmitted to the roller 423b by bringing the drive roller into contact with the roller 423b. The drive unit 423c rotates the roller 423b such that the rotational speed of the medium 500 rotated via the roller 423b is equal to the advance speed of the intermediate transfer belt 131 at the contact point with the intermediate transfer belt 131 of the transfer unit 100.

[0051] In this description, a drive device 423c is provided on the jig 423, and the roller 423b is used as a drive wheel, so that the jig 423 dynamically rotates the medium 500 in accordance with the movement of the intermediate transfer belt 131 of the transfer section 100. Alternatively, the jig 423 may simply support the medium 500 so that it can rotate freely, and the roller 423b may be used as a driven wheel so that the medium 500 rotates in accordance with the movement of the intermediate transfer belt 131. For example, if the medium 500 is made of a material with a high coefficient of friction with respect to the intermediate transfer belt 131, the medium 500 will be pulled by the intermediate transfer belt 131 at the contact point and will rotate without requiring drive by the roller 423b.

[0052] Figure 7 shows another example configuration of the jig 423 for rotatably holding the medium 500. Figure 7(A) shows the jig 423 and the medium 500 viewed in an orientation parallel to the rotation axis of the medium 500, and Figure 7(B) shows the jig 423 and the medium 500 viewed in an orientation perpendicular to the rotation axis of the medium 500. The jig 423 shown in Figures 7(A) and (B) rotatably supports the medium 500 with the central axis of the circumferential surface as the axis of rotation. The jig 423 has a retaining member 423d that rotatably holds the medium 500. The jig 423 has a built-in drive unit 423e for rotating the medium 500. The jig 423 has a structure that fits into the fasteners of the base portion 422 and is fixed to the base portion 422.

[0053] The jig 423 shown in Figures 7(A) and (B) holds the medium 500 by clamping it from both ends of the axis at the position where the central axis of the circumferential surface passes through the medium 500 using the clamping device 423d. The drive device 423e is a driving means for rotating the clamping device 423d. While holding the medium 500, the clamping device 423d receives power from the drive device 423e and rotates the medium 500 around the central axis of the circumferential surface. Various existing mechanisms can be used as the drive device 423e, and the specific structure is not limited. For example, a configuration in which the clamping device 423d is directly rotated by a motor may be used. The drive device 423e rotates the clamping device 423d so that the rotational speed of the medium 500 is equal to the advance speed of the intermediate transfer belt 131 at the contact position with the intermediate transfer belt 131 of the transfer unit 100.

[0054] In this description, a configuration was explained in which a drive device 423e is provided on the jig 423, and a retainer 423d is used as a drive wheel, causing the jig 423 to dynamically rotate the medium 500 in accordance with the movement of the intermediate transfer belt 131 of the transfer section 100. Alternatively, the jig 423 may simply support the medium 500 so that it can rotate freely, and the retainer 423d may be used as a driven wheel, causing the medium 500 to rotate in accordance with the movement of the intermediate transfer belt 131. For example, if the medium 500 is made of a material with a high coefficient of friction with respect to the intermediate transfer belt 131, the medium 500 will be pulled by the intermediate transfer belt 131 at the contact point and will rotate without requiring drive by the retainer 423d.

[0055] The jig 423 shown in Figures 7(A) and (B) holds and rotates the central axis of the circumferential surface of the medium 500, and can hold mediums 500 of various shapes that have a circumferential surface by holding the central axis of the circumferential surface. Furthermore, the jig 423 shown in Figures 7(A) and (B) can hold the medium 500 even if a part of the circumferential surface has irregularities, so as to transfer an image to the part of the circumferential surface.

[0056] Figure 8 shows an example of a medium 500 having a circumferential surface. Figure 8(A) shows a spherical medium 500, and Figure 8(B) shows a frustoconical medium 500. Figures 8(A) and (B) show the medium 500 viewed from the front side in the transport direction, perpendicular to the axis of rotation of the medium 500.

[0057] When the medium 500 is spherical, the circumferential surface is convex not only in the circumferential direction but also in the direction parallel to the central axis. Therefore, as shown in Figure 8(A), the image is transferred to a narrow region where the medium 500 and the intermediate transfer belt 131 come into contact due to the bending of the belt. However, an image of this width can be transferred over the entire circumference of the spherical medium 500. In Figure 8(A), a band-shaped image T is formed on the surface of the medium 500 in the area in contact with the intermediate transfer belt 131.

[0058] If the medium 500 is frustoconical in shape, the circumferential surface is inclined with respect to the central axis. In this case, as shown in Figure 8(B), the jig 423 holds the medium 500 by tilting its central axis in accordance with the inclination of the circumferential surface, thereby aligning the circumferential surface of the medium 500 with the surface of the intermediate transfer belt 131 of the transfer unit 100. In Figure 8(B), an image T is formed that is inclined with respect to the central axis of the circumferential surface, corresponding to the circumferential surface of the medium 500.

[0059] In the example shown in Figure 8, the transfer of images was described for cases where the circumferential surface of the medium 500 is a curved surface with curvature in a direction parallel to the central axis (Figure 8(A)) and where the circumferential surface of the medium 500 is inclined with respect to the central axis (Figure 8(B)). As described above, when using the jig 423 shown in Figure 7, images can be transferred to mediums 500 having various circumferential surfaces. Furthermore, even for mediums 500 with protrusions on the circumferential surface, such as a cup with a handle, images can be transferred to only a portion of the circumferential surface by rotating the medium within a range where the protrusions do not come into contact with the intermediate transfer belt 131 and the jig 423.

[0060] <Control of the movement of the medium 500 at the transfer position> When transferring an image to the circumferential surface of the medium 500 in the transfer unit 100, as described above, the medium 500 is rotated in accordance with the advance of the intermediate transfer belt 131 of the transfer unit 100, while the medium 500 itself must remain stationary at the transfer position while the image is being transferred. One method for stopping the movement of the medium 500 during image transfer is to have the transport mechanism 400 stop transporting the mounting base 420 on which the medium 500 is placed once the medium 500 has moved to the transfer position. Another method is to move the jig 423 relative to the base portion 422 of the mounting base 420 in the opposite direction to the transport direction of the mounting base 420, thereby stopping the position of the medium 500 relative to the transfer position of the transfer unit 100.

[0061] In the configuration described with reference to Figure 2, the jig 423 is fixed to the mounting base 420 using fasteners provided on the base portion 422. In contrast, when moving the jig 423 relative to the base portion 422, a movement path is provided on the base portion 422, and the jig 423 has a means of movement that moves along this movement path. The specific configuration of the movement path on the base portion 422 and the means of movement of the jig 423 is not particularly limited, as long as the jig 423 can move along the predetermined movement path. For example, a groove or rail may be provided on the base portion 422 as a movement path, and the jig 423 may have wheels for running on this groove or rail as a means of movement. More specifically, a rack may be used as the rail of the movement path, and a rack and pinion system using a pinion gear as the wheel of the jig 423 may be used to control the rotation of the pinion gear of the jig 423 and move the jig 423. The movement of the jig 423 may be realized by equipping the jig 423 with a drive mechanism such as a motor, allowing the jig 423 to self-propel along the movement path of the base 422. Alternatively, a means for towing the jig 423 may be provided on the movement path of the base 422.

[0062] The movement path is provided parallel to the transport direction of the mounting base 420. The jig 423 can only move in the direction along the movement path, and its movement in the width direction of the movement path is restricted. Furthermore, when moving the jig 423 relative to the base portion 422, the movement path needs to be long enough for the jig 423 to move while the image is being transferred to the medium 500. For this reason, the size of the base portion 422 relative to the jig 423 is larger compared to the configuration in which the jig 423 is fixed to the base portion 422, as described with reference to Figure 2.

[0063] Figure 9 shows the movement of the jig 423. Figure 9(A) shows the state at the start of transfer, Figure 9(B) shows the state during transfer, and Figure 9(C) shows the state at the end of transfer. When the transfer unit 100 transfers an image, the mounting base 420 is transported and the medium 500 reaches the transfer position. As shown in Figure 9(A), the jig 423 begins to move on the base 422 in the opposite direction to the transport direction of the mounting base 420. As the image is transferred to the medium 500, the jig 423 moves on the base 422, as shown in Figure 9(B), to hold the medium 500 in the transfer position. When the transfer of the image to the medium 500 is complete, as shown in Figure 9(C), the movement of the jig 423 ends, and the medium 500 is transported toward the fixing unit 200 together with the mounting base 420.

[0064] The movement mechanism for the jig 423 controls the timing of the start and end of its movement, as well as its movement speed. Specifically, the movement of the jig 423 is started when the mounting base 420 is transported and the medium 500 reaches the transfer position, and the jig 423 is moved at the same speed as the transport speed of the mounting base 420 but in the opposite direction, and the movement of the jig 423 is stopped when the transfer of the image to the medium 500 is completed. The control mechanism is implemented, for example, by a processor that controls the operation of the drive mechanism of the jig 423, and a memory that stores the control program executed by the processor and the control data. The control mechanism may be mounted on the jig 423, or the operation of the jig 423 may be controlled by an external control device. In the latter case, in order to transmit control signals to the drive mechanism of the jig 423 even while the mounting base 420 is being transported, it is necessary to provide a signal path by means of connecting a signal cable to the jig 423. The positions of the medium 500 and the jig 423 may be determined, for example, by installing a sensor inside the housing of the image forming apparatus 10 and determining it based on the detection signal of this sensor, or by calculating it based on the position of the mounting base 420 on the transport rail 410. The position of the mounting base 420 on the transport rail 410 can be determined from the information used for transport control in the transport mechanism 400. Alternatively, the length of the movement path of the base portion 422 may be set to a length such that the jig 423 reaches the end on the side where the movement ends after the jig 423 starts moving and when the transfer of the image to the medium 500 is completed.

[0065] Although embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above embodiments. For example, in the above embodiments, the mechanism for rotating the medium 500 and the mechanism for moving the jig 423 relative to the base portion 422 are not limited to the above embodiments, and various configurations can be adopted depending on the type and shape of the medium 500. In addition, various modifications and substitutions of configurations that do not depart from the technical concept of the present invention are included in the present invention.

[0066] <Note> (((1))) An image forming apparatus comprising: a transfer unit that contacts an object and transfers an image onto the object; a holding unit that holds the object having a circumferential surface such that the circumferential surface rotates along the transfer direction of the transfer unit; and a transport unit that transports the holding unit holding the object along a transport path, wherein the transfer unit contacts the circumferential surface of the object maintained in the transfer position and transfers an image to the circumferential surface of the object in the circumferential direction as the object rotates. (((2))) The image forming apparatus according to (((1))), characterized in that the holding portion further comprises a movable base portion that moves along the transport path by the transport portion, and a support portion that is provided on the movable base portion so as to be movable in the opposite direction to the transport direction by the transport portion and rotatably supports the object. (((3))) The image forming apparatus according to (((2))), wherein the holding portion further comprises a drive mechanism that moves the support portion relative to the movable base portion in the opposite direction to the transport direction by the transport portion and at the same speed as the transport speed by the transport portion. (((4))) The image forming apparatus according to any one of (((1))) to (((3))), characterized in that the holding unit comprises a support base for supporting the object in a placed position, and the support base is provided with a roller having a rotation axis substantially perpendicular to the transport direction by the transport unit and supporting the circumferential surface of the object. (((5))) The image forming apparatus according to (((4))), characterized in that the roller of the support base is provided to support the object in an area other than the image area on which the image of the object is transferred. (((6))) The image forming apparatus according to (((4))) or (((5))), characterized in that the support base is provided with a driving means for rotating the roller so that the object rotates at a speed corresponding to the image transfer speed by the transfer unit. (((7))) The image forming apparatus according to any one of (((1))) to (((3))), characterized in that the holding portion comprises a pivot portion that supports the object with the central axis of the circumferential surface containing the image region on which the image is transferred as the axis of rotation. (((8))) The image forming apparatus according to (((7))), characterized in that it comprises a driving means for driving the rotation axis so that the object rotates at a speed corresponding to the image transfer speed by the transfer unit.

[0067] According to the image forming apparatus described in (((1))), compared to a configuration in which a medium is fixed to a transport means and transported for printing, an image can be printed along the circumference on a circumferential surface. According to the image forming apparatus described in (((2))), compared to a configuration in which the medium is fixed to the transport means, the position of the object can be maintained at the transfer position when the image is transferred by the transfer unit. According to the image forming apparatus described in (((3))), the object can be stably held in the transfer position compared to a configuration that does not use a driving means. According to the image forming apparatus described in (((4))), compared to a configuration in which the medium is fixed to the transport means, the object can be rotated by rollers to transfer an image onto the circumferential surface. According to the image forming apparatus described in (((5))), unlike a configuration in which rollers are provided at positions corresponding to the image area, an image can be transferred over the entire circumferential surface of the object. According to the image forming apparatus described in (((6))), compared to a configuration in which the object is passively rotated according to the operation of the transfer unit, the object can be rotated stably and an image transferred regardless of its material. According to the image forming apparatus described in (((7))), compared to a configuration in which the medium is fixed to the transport means, the object can be rotated by setting the rotation axis and an image can be transferred to the circumferential surface. According to the image forming apparatus described in (((8))), compared to a configuration in which the object is passively rotated according to the operation of the transfer unit, the object can be rotated stably and an image transferred regardless of its material. [Explanation of symbols]

[0068] 10…Image forming apparatus, 100…Transfer section, 110…Developing apparatus, 120…Primary transfer roll, 131…Intermediate transfer belt, 132, 133…Rollers, 140…Backup roll, 150…Cleaning apparatus, 200…Fixing section, 201…Inlet, 202…Outlet, 210…Heat source, 220, 230, 240…Shutter, 300…Media loading / unloading section, 400…Transport mechanism, 410…Transport rail, 420…Mounting base, 421…Legs, 422…Base, 423…Jig, 423a…Base, 423b…Roller, 423c…Drive unit, 423d…Presser, 423e…Drive unit, 500…Media

Claims

1. A transfer unit that contacts an object and transfers an image onto the object, A holding unit that holds the object having a circumferential surface such that the circumferential surface rotates along the transfer direction of the transfer unit, The system comprises a transport unit that transports the holding unit holding the object along a transport path, The transfer unit contacts the circumferential surface of the object maintained in the transfer position, and as the object rotates, transfers an image to the circumferential surface of the object in the circumferential direction. The holding unit includes a movable base unit that moves along the transport path by the transport unit, A support portion is provided on the movable base portion so as to be movable in the opposite direction to the transport direction by the transport portion, and rotatably supports the object, An image forming apparatus further characterized by comprising the following:

2. The image forming apparatus according to claim 1, wherein the holding portion further comprises a drive mechanism that moves the support portion relative to the movable base portion in the opposite direction to the transport direction by the transport portion and at the same speed as the transport speed by the transport portion.

3. A transfer unit that contacts an object and transfers an image onto the object, A holding unit that holds the object having a circumferential surface such that the circumferential surface rotates along the transfer direction of the transfer unit, The system comprises a transport unit that transports the holding unit holding the object along a transport path, The transfer unit contacts the circumferential surface of the object maintained in the transfer position, and as the object rotates, transfers an image to the circumferential surface of the object in the circumferential direction. The holding part includes a support base that supports the object in the state in which it is placed, The support base is provided with a roller that has a rotation axis substantially perpendicular to the conveying direction of the conveying unit and supports the circumferential surface of the object, An image forming apparatus characterized in that the roller of the support base is provided to support the object in an area other than the image area on which the image of the object is transferred.

4. The image forming apparatus according to claim 3, characterized in that the support base is provided with a driving means for rotating the rollers such that the object rotates at a speed corresponding to the image transfer speed by the transfer unit.

5. The image forming apparatus according to claim 1, characterized in that the holding portion includes a pivot portion that supports the object with the central axis of the circumferential surface containing the image region on which the image is transferred as the axis of rotation.

6. The image forming apparatus according to claim 5, further characterized by comprising a driving means for driving the rotation axis so that the object rotates at a speed corresponding to the image transfer speed by the transfer unit.

Images