JP2018165766A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming apparatus that enables a user to easily clean the apparatus.SOLUTION: An image forming apparatus of the present invention comprises: a conveying part that has a conveyance member carrying developer images and conveys and circulates the conveyance member in a first conveyance direction to convey the developer images; a transfer member that is arranged opposite to the conveyance member at a predetermined position and transfers the developer images carried on the conveyance member to a recording medium: a first detection part that is arranged downstream of the predetermined position in the first conveyance direction of the conveyance member and detects an attachment attached to the conveyance member; and a control part that controls the conveyance member to be conveyed in a second conveyance direction on the basis of a first result of detection performed by the first detection part when the conveying part conveys the conveyance member in the first conveyance direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium.

  As a recording medium, there is a so-called label paper in which labels are temporarily attached to a long mount. Patent Document 1 discloses an image forming apparatus that forms an image on label paper.

Japanese Unexamined Patent Publication No. 2017-19107

  In an image forming apparatus that forms an image on a label sheet, when the label sheet is being transported, for example, label debris around the label (hereinafter also referred to as an unnecessary item) may be peeled off inside the image forming apparatus. In such a case, the user cleans the inside and removes the removed label residue. Therefore, in the image forming apparatus, it is desired that the user can easily perform cleaning.

  It is desirable to provide an image forming apparatus that can be easily cleaned by a user.

  An image forming apparatus according to an embodiment of the present invention includes a conveyance unit, a transfer member, a first detection unit, and a control unit. The transport unit includes a transport member that carries a developer image, and transports the developer image by circulating and transporting the transport member in the first transport direction. The transfer member is disposed so as to face the conveyance member at a predetermined position, and transfers the developer image carried on the conveyance member to a recording medium. A 1st detection part is arrange | positioned downstream of the predetermined position in the 1st conveyance direction of a conveyance member, and detects the deposit | attachment adhering to the conveyance member. The control unit conveys the conveying member in the second conveying direction based on the first detection result by the first detecting unit when the conveying unit conveys the conveying member in the first conveying direction. It is.

  According to the image forming apparatus in one embodiment of the present invention, the transport member is transported in the second transport direction based on the first detection result by the first detection unit, so that the user performs cleaning. It can be made easier.

1 is an explanatory diagram illustrating a configuration example of an image forming apparatus according to a first embodiment. FIG. 2 is an explanatory diagram illustrating a configuration example of a recording medium illustrated in FIG. 1. FIG. 2 is an explanatory diagram illustrating a configuration example of an image forming unit illustrated in FIG. 1. FIG. 2 is a block diagram illustrating a configuration example of an image forming apparatus illustrated in FIG. 1. 3 is a flowchart illustrating an operation example of the image forming apparatus illustrated in FIG. 1. 6 is another flowchart illustrating an operation example of the image forming apparatus illustrated in FIG. 1. FIG. 6 is an image diagram illustrating an operation example of the image forming apparatus illustrated in FIG. 1. FIG. 10 is another image diagram illustrating an operation example of the image forming apparatus illustrated in FIG. 1. FIG. 10 is another image diagram illustrating an operation example of the image forming apparatus illustrated in FIG. 1. FIG. 10 is another image diagram illustrating an operation example of the image forming apparatus illustrated in FIG. 1. FIG. 10 is another image diagram illustrating an operation example of the image forming apparatus illustrated in FIG. 1. 6 is another flowchart illustrating an operation example of the image forming apparatus illustrated in FIG. 1. FIG. 6 is an explanatory diagram illustrating an operation example of the image forming apparatus illustrated in FIG. 1. FIG. 10 is an explanatory diagram illustrating another operation example of the image forming apparatus illustrated in FIG. 1. FIG. 10 is an explanatory diagram illustrating another operation example of the image forming apparatus illustrated in FIG. 1. FIG. 10 is an explanatory diagram illustrating another operation example of the image forming apparatus illustrated in FIG. 1. 10 is a flowchart illustrating an operation example of an image forming apparatus according to a modification of the first embodiment. It is explanatory drawing showing the example of 1 structure of the image forming apparatus which concerns on the other modification of 1st Embodiment. It is explanatory drawing showing the example of 1 structure of the image forming apparatus which concerns on 2nd Embodiment. FIG. 15 is a block diagram illustrating a configuration example of the image forming apparatus illustrated in FIG. 14. 15 is a flowchart illustrating an operation example of the image forming apparatus illustrated in FIG. 15 is another flowchart illustrating an operation example of the image forming apparatus illustrated in FIG. 14. 15 is another flowchart illustrating an operation example of the image forming apparatus illustrated in FIG. 14. It is explanatory drawing showing the example of 1 structure of the image forming apparatus which concerns on the modification of 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
1. First Embodiment 2. FIG. Second embodiment

<1. First Embodiment>
[Configuration example]
FIG. 1 shows a configuration example of an image forming apparatus (image forming apparatus 1) according to a first embodiment of the present invention. The image forming apparatus 1 is, for example, a printer that forms an image on a so-called label sheet using an electrophotographic method. The image forming apparatus 1 includes a medium supply unit 10 and an image forming unit 20.

  The medium supply unit 10 pulls out the recording medium 9 from a roll around which the recording medium 9 is wound and supplies the recording medium 9 to the image forming unit 20.

  2A and 2B show an example of the configuration of the recording medium 9. FIG. 2A shows the surface (label surface) of the recording medium 9, and FIG. 2B shows the direction of arrows II in FIG. A cross section is shown, and (C) shows the back surface of the recording medium 9. The recording medium 9 has a plurality of labels 9a and a mount 9c. The plurality of labels 9a are arranged side by side in the longitudinal direction of the recording medium 9 on the surface (label surface) of the recording medium 9, and are temporarily attached to the mount 9c. Further, there is an unnecessary object 9b which is a label residue around the label 9a, and this unnecessary object 9b is also temporarily attached to the mount 9c. A marker 9d is printed on the back surface of the mount 9c. In this example, the marker 9d is formed at a position corresponding to the gap between the adjacent labels 9a in the juxtaposed direction of the labels 9a (lateral direction in FIG. 2).

  The medium supply unit 10 (FIG. 1) includes a medium fixing unit 11, a conveyance roller 12, a label sensor 13, and a cutting unit 14. The conveyance roller 12, the label sensor 13, and the cutting unit 14 are arranged in this order along the conveyance path 8 in the conveyance direction F <b> 1 of the recording medium 9.

  The medium fixing unit 11 fixes a roll around which the recording medium 9 is wound so as to be rotatable about an axis. Thereby, the recording medium 9 is pulled out from the roll as the roll rotates.

  The conveyance roller 12 is configured by a pair of rollers that sandwich the conveyance path 8, and is configured to pull out the recording medium 9 from the roll and convey it along the conveyance path 8.

  The label sensor 13 detects the position of the label 9a of the recording medium 9. Specifically, the label sensor 13 is configured using, for example, a reflective sensor, and detects the marker 9d based on reflected light when the back surface of the recording medium 9 is irradiated with light, whereby the position of the label 9a is detected. Is supposed to be detected. The image forming apparatus 1 determines the cutting position of the recording medium 9 by the cutting unit 14 based on the detection result of the label sensor 13.

  The cutting unit 14 is a member that cuts the recording medium 9. Based on the detection result of the label sensor 13, the cutting unit 14 cuts the recording medium 9 in units of a predetermined number of labels 9a designated by the user, for example.

  The image forming unit 20 forms an image on the label surface of the recording medium 9 supplied from the medium supply unit 10. The image forming unit 20 includes five image forming units 30 (image forming units 30Y, 30M, 30C, 30K, and 30W), five exposure units 39 (exposure units 39Y, 39M, 39C, 39K, and 39W), and a belt unit. 40 and a line sensor 61.

  The five image forming units 30 each form a toner image. Specifically, the image forming unit 30Y forms a yellow toner image, the image forming unit 30M forms a magenta toner image, and the image forming unit 30C forms a cyan toner image. The image forming unit 30K forms a black toner image, and the image forming unit 30W forms a white toner image. Each image forming unit 30 is configured to be detachable. The image forming units 30Y, 30M, 30C, 30K, and 30W are arranged in this order in the conveyance direction F2 of a transfer belt 42 (described later) of the belt unit 40.

  The five exposure units 39 are members that respectively irradiate light onto the photoreceptors 31 (described later) of the five image forming units 30. Specifically, the exposure unit 39Y irradiates the photosensitive member 31 of the image forming unit 30Y with light, and the exposure unit 39M irradiates the photosensitive member 31 of the image forming unit 30M with light, thereby exposing the exposure unit 39C. Irradiates the photosensitive member 31 of the image forming unit 30C with light, the exposure unit 39K irradiates the photosensitive member 31 of the image forming unit 30K with light, and the exposure unit 39W sets the photosensitive member of the image forming unit 30W. The body 31 is irradiated with light. As a result, the photoreceptors 31 are exposed by the exposure units 39, respectively. As a result, an electrostatic latent image is formed on the surface of each photoconductor 31.

  FIG. 3 illustrates a configuration example of the image forming unit 30. The image forming unit 30 includes a photoreceptor 31, a cleaning blade 32, a charging roller 33, a developing roller 34, a developing blade 35, a supply roller 36, and a toner storage unit 37. In FIG. 3, the exposure unit 39 is also drawn for convenience of explanation.

  The photoreceptor 31 is a member that carries an electrostatic latent image on the surface (surface layer portion). In this example, the photoconductor 31 rotates counterclockwise by power transmitted from a photoconductor motor (not shown). The photoreceptor 31 is charged by the charging roller 33 and exposed by the exposure unit 39. As a result, an electrostatic latent image is formed on the surface of the photoreceptor 31. The toner is supplied from the developing roller 34 so that a toner image corresponding to the electrostatic latent image is formed (developed) on the photoreceptor 31.

  The cleaning blade 32 is a member that scrapes and cleans the toner remaining on the surface (surface layer portion) of the photoreceptor 31. The cleaning blade 32 is disposed so as to come into contact with the surface of the photoconductor 31 with a counter (projecting in a direction opposite to the rotation direction of the photoconductor 31) and pressed against the photoconductor 31 with a predetermined pressing amount. Are arranged in such a way.

  The charging roller 33 is a member that charges the surface (surface layer portion) of the photoreceptor 31. The charging roller 33 is disposed so as to be in contact with the surface (circumferential surface) of the photoreceptor 31 and is disposed so as to be pressed against the photoreceptor 31 with a predetermined pressing amount. In this example, the charging roller 33 rotates clockwise according to the rotation of the photosensitive member 31. A predetermined charging voltage is applied to the charging roller 33 by a voltage generator 56 (described later).

  The developing roller 34 is a member that carries charged toner on the surface. The developing roller 34 is disposed so as to be in contact with the surface (circumferential surface) of the photoreceptor 31 and is disposed so as to be pressed against the photoreceptor 31 with a predetermined pressing amount. In this example, the developing roller 34 is rotated clockwise by the power transmitted from the photoreceptor motor (not shown). A predetermined developing voltage is applied to the developing roller 34 by a voltage generator 56 (described later).

  The developing blade 35 abuts on the surface of the developing roller 34 to form a toner layer (toner layer) on the surface of the developing roller 34 and regulate (control, adjust) the thickness of the toner layer. It is a member. The developing blade 35 is obtained by bending a plate-like elastic member made of, for example, stainless steel into an L shape. The developing blade 35 is disposed so that the bent portion is in contact with the surface of the developing roller 34 and is disposed so as to be pressed against the developing roller 34 with a predetermined pressing amount.

  The supply roller 36 is a member that supplies the toner stored in the toner container 37 to the developing roller 34. The supply roller 36 is disposed so as to be in contact with the surface (circumferential surface) of the developing roller 34 and is disposed so as to be pressed against the developing roller 34 with a predetermined pressing amount. In this example, the supply roller 36 is rotated clockwise by the power transmitted from the photoreceptor motor (not shown). As a result, friction occurs between the surface of the supply roller 36 and the surface of the developing roller 34, and the toner is charged by so-called frictional charging. A predetermined supply voltage is applied to the supply roller 36 by a voltage generator 56 (described later).

  The toner storage unit 37 stores toner. Specifically, the toner container 37 of the image forming unit 30Y stores yellow toner, the toner container 37 of the image forming unit 30M stores magenta toner, and the toner container 37 of the image forming unit 30C The toner container 37 of the image forming unit 30K stores black toner, and the toner container 37 of the image forming unit 30W stores white toner.

  With this configuration, in the image forming unit 30, the photoreceptor 31 is charged by the charging roller 33 and exposed by the exposure unit 39. As a result, an electrostatic latent image is formed on the surface of the photoreceptor 31. Further, the toner stored in the toner storage unit 37 is charged by the supply roller 36 and the developing roller 34 and supplied to the photoconductor 31. As a result, a toner image corresponding to the electrostatic latent image is formed (developed) on the photoreceptor 31.

  The belt unit 40 (FIG. 1) includes five primary transfer rollers 41 (primary transfer rollers 41Y, 41M, 41C, 41K, and 41W), a transfer belt 42, a drive roller 43, idle rollers 44 and 45, A secondary transfer backup roller 46, an idle roller 47, and a cleaning device 48 are included. The belt unit 40 is configured to be detachable.

  The five primary transfer rollers 41 are members for electrostatically transferring the toner images formed by the five image forming units 30 onto the transfer surface of the transfer belt 42. The primary transfer roller 41Y is disposed opposite to the photoreceptor 31 of the image forming unit 30Y with the transfer belt 42 interposed therebetween, and the primary transfer roller 41M is disposed on the photoreceptor 31 of the image forming unit 30M with the transfer belt 42 interposed therebetween. The primary transfer roller 41C is disposed to face the photoconductor 31 of the image forming unit 30C with the transfer belt 42 interposed therebetween, and the primary transfer roller 41K is disposed to the image forming unit 30 with the transfer belt 42 interposed therebetween. The primary transfer roller 41W is disposed opposite to the photoreceptor 31 of the image forming unit 30W with the transfer belt 42 interposed therebetween. A predetermined primary transfer voltage is applied to each primary transfer roller 41 by a voltage generator 56 (described later). As a result, in the image forming apparatus 1, the toner images formed by the image forming units 30 are transferred (primary transfer) onto the transfer surface of the transfer belt 42.

  The transfer belt 42 carries a toner image on the transfer surface and conveys the toner image to a secondary transfer unit 25 (described later). The transfer belt 42 is an endless elastic belt made of, for example, a high-resistance semiconductive plastic film. The transfer belt 42 is stretched (strung) by a drive roller 43, idle rollers 44 and 45, a secondary transfer backup roller 46, and an idle roller 47. The transfer belt 42 is circulated and conveyed according to the rotation of the drive roller 43.

  The drive roller 43 circulates and conveys the transfer belt 42. In this example, the drive roller 43 is disposed upstream of the five image forming units 30 in the conveyance direction F2 of the transfer belt 42, and rotates clockwise in this example by power transmitted from a transfer belt motor (not shown). . As a result, the drive roller 43 circulates and conveys the transfer belt 42.

  The idle rollers 44 and 45 are driven to rotate clockwise in this example in accordance with the circulation and conveyance of the transfer belt 42. In this example, the idle roller 44 is disposed downstream of the five image forming units 30 in the conveyance direction F <b> 2 of the transfer belt 42, and the idle roller 45 is disposed downstream of the idle roller 44.

  In this example, the secondary transfer backup roller 46 is driven to rotate clockwise in accordance with the circulation and conveyance of the transfer belt 42. The secondary transfer backup roller 46 is disposed opposite to the secondary transfer roller 24 with the conveyance path 8 and the transfer belt 42 interposed therebetween. The secondary transfer backup roller 46 constitutes the secondary transfer unit 25 together with the secondary transfer roller 24.

  The idle roller 47 is constituted by a pair of rollers that sandwich the transfer belt 42, and in this example, the idle roller 47 is driven to rotate counterclockwise in accordance with the circulating conveyance of the transfer belt 42. The idle roller 47 is disposed downstream of the secondary transfer unit 25 in the conveyance direction F <b> 2 of the transfer belt 42.

  The cleaning device 48 is a device that cleans the transfer belt 42 by scraping off toner remaining on the transfer surface of the transfer belt 42. Then, the scraped toner is accommodated in a container of the cleaning device 48.

  The line sensor 61 has light receiving elements arranged in a row and images the transfer surface of the transfer belt 42. The line sensor 61 is disposed downstream of the secondary transfer unit 25 and upstream of the cleaning device 48 in the transport direction F2 of the transfer belt 42.

  The image forming unit 20 further includes transport rollers 21 and 22, a label sensor 23, a secondary transfer roller 24, a fixing unit 26, and a discharge roller 27.

  The conveyance roller 21 is configured by a pair of rollers that sandwich the conveyance path 8, and conveys the recording medium 9 supplied from the medium supply unit 10 along the conveyance path 8. The conveyance roller 22 includes a pair of rollers that sandwich the conveyance path 8, and conveys the recording medium 9 conveyed by the conveyance roller 21 toward the secondary transfer unit 25 along the conveyance path 8. Is.

  The label sensor 23 detects the position of the label 9a of the recording medium 9. Specifically, the label sensor 23 is configured using, for example, a reflection type sensor, and detects the marker 9d based on the reflected light when the back surface of the recording medium 9 is irradiated with light, thereby detecting the position of the label 9a. Is supposed to be detected. The image forming apparatus 1 adjusts the transfer position of the toner image on the recording medium 9 based on the detection result of the label sensor 23.

  The secondary transfer roller 24 is a member for transferring the toner image on the transfer surface of the transfer belt 42 to the label 9 a of the recording medium 9. The secondary transfer roller 24 is disposed to face the secondary transfer backup roller 46 with the conveyance path 8 and the transfer belt 42 interposed therebetween. The secondary transfer roller 24 and the secondary transfer backup roller 46 constitute a secondary transfer unit 25. A predetermined secondary transfer voltage is applied to the secondary transfer roller 24 by a voltage generator 56 (described later). As a result, in the image forming apparatus 1, the toner image on the transfer surface of the transfer belt 42 is transferred (secondary transfer) to the label 9 a of the recording medium 9.

  The fixing unit 26 is a member that fixes the toner image transferred onto the recording medium 9 to the recording medium 9 by applying heat and pressure to the recording medium 9. The fixing unit 26 includes a heat roller 26a and a pressure roller 26b. For example, the heat roller 26 a includes a heater such as a halogen lamp inside, and is a member that applies heat to the toner on the recording medium 9. The pressure roller 26b is a member that applies pressure to the toner on the recording medium 9, and is disposed so that a pressure contact portion is formed between the pressure roller 26b and the heat roller 26a. Thereby, in the fixing unit 26, the toner on the recording medium 9 is heated, melted, and pressurized. As a result, the toner image is fixed on the recording medium 9.

  The discharge roller 27 includes a pair of rollers that sandwich the conveyance path 8 and is a member that discharges the recording medium 9 to the outside of the image forming apparatus 1.

  FIG. 4 illustrates an example of a control mechanism in the image forming apparatus 1. The image forming apparatus 1 includes a communication unit 51, an image processing unit 52, an operation unit 53, a display unit 54, an exposure control unit 55, a voltage generation unit 56, a motor control unit 57, and a fixing control unit 58. And an unnecessary object detection unit 60 and a control unit 59.

  The communication unit 51 performs communication using, for example, a LAN (Local Area Network), a USB (Universal Serial Bus), a Centronics, and the like, and receives print data transmitted from a host computer (not shown), for example. . The image processing unit 52 generates image data (bitmap data) based on the print data received by the communication unit 51.

  The operation unit 53 receives user operations and is configured using various buttons, a touch panel, and the like, for example. The display unit 54 displays an operation state of the image forming apparatus 1 and is configured using, for example, a liquid crystal display or various indicators.

  The exposure control unit 55 controls the operation of the five exposure units 39 using the image data generated by the image processing unit 52 based on an instruction from the control unit 59. The voltage generation unit 56 generates various voltages (charging voltage, development voltage, supply voltage, primary transfer voltage, secondary transfer voltage, etc.) necessary for image formation based on instructions from the control unit 59. . The motor control unit 57 controls the operation of various motors (photoreceptor motor, transfer belt motor, etc.) in the image forming apparatus 1 based on instructions from the control unit 59. The fixing control unit 58 controls the operation of the fixing unit 26 by operating the heater of the fixing unit 26 based on an instruction from the control unit 59.

  The belt unit 40 includes a storage unit 40a. The storage unit 40a is configured using, for example, an RFID (Radio Frequency Identifier) tag and the like, and can store information such as alarm information INF (described later) based on an instruction from the control unit 59. It has become.

  The unnecessary object detection unit 60 detects whether or not the unnecessary object 9 b (label residue) is attached to the transfer belt 42 based on the detection result of the line sensor 61. The unnecessary object detection unit 60 includes a line sensor 61, an image analysis unit 62, and a determination unit 63. The image analysis unit 62 performs image analysis based on the image (image P1) indicated by the image data generated by the image processing unit 52 and the image based on the imaging result of the line sensor 61 (captured image P2). . The determination unit 63 determines whether or not the unnecessary material 9 b is attached to the transfer belt 42 based on the image analysis result by the image analysis unit 62.

  The control unit 59 controls the overall operation of the image forming apparatus 1 by controlling the operation of each block in the image forming apparatus 1. As will be described later, the control unit 59 temporarily stops the mechanical operation of the image forming apparatus 1 when the unnecessary material detection unit 60 detects that the unnecessary material 9b is attached to the transfer belt 42. In addition, it also has a function of circulating and conveying the transfer belt 42 in the direction opposite to the conveyance direction F2. Accordingly, in the image forming apparatus 1, the transfer belt 42 can be circulated and conveyed until the portion of the transfer belt 42 to which the unnecessary material 9b is attached moves, for example, near the five primary transfer rollers 41. As a result, as shown in FIG. The user can easily clean the transfer belt 42.

  The function of the control unit 59 may be realized by using hardware or software, for example.

  Here, the transfer belt 42 corresponds to a specific example of “conveying member” in the invention. The belt unit 40 corresponds to a specific example of a “conveying unit” in the present invention. The secondary transfer roller 24 corresponds to a specific example of “transfer member” in the invention. The line sensor 61 corresponds to a specific example of “first detection unit” in the invention. The image analysis unit 62, the determination unit 63, and the control unit 59 correspond to a specific example of “control unit” in the present invention. The image forming unit 30 corresponds to a specific example of “developing unit” in the invention.

[Operation and Action]
Next, the operation and action of the image forming apparatus 1 according to the present embodiment will be described.

(Overview of overall operation)
First, an overview of the overall operation of the image forming apparatus 1 will be described with reference to FIGS. When the communication unit 51 receives the print data, the control unit 59 controls each block of the image forming apparatus 1 so that the image forming apparatus 1 performs a printing operation. The image processing unit 52 generates image data (bitmap data) based on the print data. The exposure control unit 55 controls the operations of the five exposure units 39 using the image data generated by the image processing unit 52. The voltage generator 56 generates various voltages (charging voltage, developing voltage, supply voltage, primary transfer voltage, secondary transfer voltage, etc.) necessary for image formation. The motor control unit 57 controls operations of various motors (such as a photoconductor motor and a transfer belt motor) in the image forming apparatus 1. The fixing control unit 58 controls the operation of the fixing unit 26 by operating the heater of the fixing unit 26.

  In the five image forming units 30, an electrostatic latent image is formed on the surface of the photoreceptor 31, and a toner image corresponding to the electrostatic latent image is formed (developed). The five primary transfer rollers 41 respectively transfer (primary transfer) the toner images formed on the photoreceptor 31 of the corresponding image forming unit 30 onto the transfer surface of the transfer belt 42. The toner image on the transfer belt 42 is conveyed to the secondary transfer unit 25 when the transfer belt 42 is circulated and conveyed.

  The conveyance roller 12 pulls out the recording medium 9 from the roll around which the recording medium 9 is wound, and conveys the recording medium 9 along the conveyance path 8. The label sensor 13 detects the position of the label 9 a of the recording medium 9. Based on the detection result of the label sensor 13, the cutting unit 14 cuts the recording medium 9 in units of a predetermined number of labels 9a designated by the user, for example. The transport rollers 21 and 22 transport the recording medium 9 along the transport path 8. The label sensor 23 detects the position of the label 9a of the recording medium 9.

  The secondary transfer unit 25 transfers (secondary transfer) the toner image on the transfer surface of the transfer belt 42 to the transfer surface (label surface) of the recording medium 9. The fixing unit 26 fixes the toner image on the recording medium 9. The discharge roller 27 discharges the recording medium 9 on which the toner image is fixed by the fixing unit 26 from the image forming apparatus 1.

  After the secondary transfer unit 25 transfers the toner image on the transfer belt 42 to the recording medium 9 (secondary transfer), the transfer belt 42 is continuously circulated and conveyed. The line sensor 61 images the transfer surface of the transfer belt 42. The cleaning device 48 cleans the transfer belt 42 by scraping off the toner remaining on the transfer surface of the transfer belt 42. Then, the transfer belt 42 is conveyed to the image forming unit 30.

(Detection of unnecessary object 9b)
In the image forming apparatus 1, when the recording medium 9 is transported along the transport path 8, for example, there is a possibility that label waste (unnecessary material 9 b) around the label 9 a is peeled off inside the image forming apparatus. The unnecessary material 9b peeled off in this way may adhere to the transfer belt 42 in the secondary transfer unit 25, for example. In this case, since the transfer belt 42 to which the unnecessary material 9b adheres is circulated and conveyed in the conveyance direction F2, the belt unit 40 may be broken. In addition, when the transfer belt 42 to which the unnecessary material 9b adheres is circulated and conveyed, if the unnecessary material 9b reaches the image forming unit 30, the image forming unit 30 may break down. In view of this, in the image forming apparatus 1, a line sensor 61 that images the transfer belt 42 is provided downstream of the secondary transfer unit 25 in the conveyance direction F <b> 2 of the transfer belt 42, It is detected whether or not the unnecessary material 9b is attached to the belt 42. When the unwanted matter 9b adheres to the transfer belt 42, the secondary transfer roller 24 and the transfer belt 42 are separated from each other, and the five image forming units 30 and the transfer belt 42 are separated from each other. 42 is circulated and conveyed in a direction opposite to the conveying direction F2. Accordingly, in the image forming apparatus 1, the transfer belt 42 can be circulated and conveyed until the portion of the transfer belt 42 to which the unnecessary material 9b is attached moves, for example, near the five primary transfer rollers 41. As a result, as shown in FIG. This makes it easier for the user to clean the transfer belt 42. This operation will be described in detail below.

  5A and 5B show an example of the operation of the image forming apparatus 1 when detecting the unnecessary object 9b.

  First, the control unit 59 confirms whether the image forming apparatus 1 is printing (step S101). If printing is not in progress ("N" in step S101), this flow ends.

  In step S101, when printing is in progress (“Y” in step S101), the unwanted object detection unit 60 acquires an image (captured image P2) using the line sensor 61 (step S102).

  Next, the image analysis unit 62 of the unnecessary object detection unit 60 removes the image of the region W where the toner image is arranged from the captured image P2 (step S103). Specifically, the image analysis unit 62 first specifies the region W where the toner image is arranged based on the image (image P1) indicated by the image data generated by the image processing unit 52. Then, the image analysis unit 62 obtains an analysis image P3 by removing the image of the region W from the captured image P2.

  Then, the determination unit 63 determines whether there is an unnecessary object 9b based on the analysis image P3 (step S104). Specifically, the determination unit 63 compares the pixel value of each pixel in the analysis image P3 with a predetermined pixel value, and when the pixel value exceeds a predetermined pixel value in a predetermined pixel area. It is determined that there is an unnecessary object 9b. That is, the determination unit 63 determines that there is an unnecessary object 9b when a large pixel value that cannot be a normal operation is confirmed in a pixel region having a predetermined size. If there is no unnecessary object 9b ("N" in step S104), the process returns to step S101.

  Hereinafter, the operations of steps S102 to S104 will be described with some examples. First, an operation when there is no unnecessary object 9b will be described, and then an operation when there is an unnecessary object 9b will be described.

  FIG. 6 illustrates an example of the image P1 indicated by the image data generated by the image processing unit 52. FIG. 7A shows an example of the captured image P2 when there is no unnecessary object 9b, and FIG. 7B shows the analysis image P3 obtained by removing the image of the region W from the captured image P2 shown in FIG. 7A. is there. 6, 7A and 7B, for example, white indicates that the pixel value is low, and black indicates that the pixel value is high.

  In this example, the image processing unit 52 generates a bitmap image (image P1) in which ten alphabets from “A” to “K” are arranged side by side as shown in FIG. Each image forming unit 30 generates a toner image based on the image P1. This toner image is transferred to the transfer surface of the transfer belt 42, and is transferred to the secondary transfer unit 25 when the transfer belt 42 is transferred in the transfer direction F2. As a result, the transfer belt 42 carries a toner image as shown in FIG. 6 upstream of the secondary transfer unit 25.

  The secondary transfer unit 25 transfers (secondary transfer) the toner image on the transfer surface of the transfer belt 42 to the transfer surface (label surface) of the recording medium 9. As a result, most of the toner on the transfer surface of the transfer belt 42 moves to the recording medium 9, but some toner remains on the transfer surface of the transfer belt 42. Therefore, when the line sensor 61 images the transfer surface of the transfer belt 42, a captured image P2 in which the alphabet remains thin is obtained as shown in FIG. 7A (step S102).

  The image analysis unit 62 removes the image of the region W where the toner image is arranged from the captured image P2 (step S103). First, the image analysis unit 62 specifies a pixel region constituting the alphabet as a region W based on the image P1 (FIG. 6). Then, the image analysis unit 62 removes the image of the region W from the captured image P2 (FIG. 7A). Specifically, the image analysis unit 62 sets the pixel value in the pixel region corresponding to the region W to “0” from the captured image P2 (FIG. 7A). Thereby, as shown in FIG. 7B, the image analysis unit 62 obtains an analysis image P3 in which the pixel value is almost “0” in the entire region.

  Then, the determination unit 63 determines whether there is an unnecessary object 9b based on the analysis image P3 (step S104). Specifically, the determination unit 63 compares the pixel value of each pixel in the analysis image P3 with a predetermined pixel value, and determines whether the pixel value exceeds a predetermined pixel value in a pixel area having a predetermined size. Check. In this example, as shown in FIG. 7B, the pixel value is almost “0” in the entire region. Therefore, the determination unit 63 determines that there is no unnecessary object 9b.

  On the other hand, when the unwanted material 9b adheres to the transfer belt 42, the captured image P2 includes information about the unwanted material 9b in addition to the remaining toner.

  FIG. 8A shows an example of a captured image P2 when there is an unnecessary object 9b, and FIG. 8B shows an analysis image P3 obtained by removing the region W from the captured image P2 shown in FIG. 8A. In FIG. 8A, a black portion indicates an unnecessary object 9b.

  Also in this case, the image analysis unit 62 removes the image of the pixel region (region W) constituting the alphabet from the captured image P2 (FIG. 8A) (step S103). Thereby, as shown in FIG. 8B, the image analysis unit 62 obtains an analysis image P3 including information on the unnecessary object 9b. Then, the determination unit 63 determines whether there is an unnecessary object 9b based on the analysis image P3 (step S104). In this example, since the analysis image P3 includes information about the unnecessary object 9b, the determination unit 63 has a pixel value that exceeds a predetermined pixel value in a pixel region having a predetermined size. As a result, the determination unit 63 determines that there is an unnecessary object 9b.

  In step S104 (FIG. 5A), when there is an unnecessary object 9b (“Y” in step S104), the control unit 59 is based on an instruction from the determination unit 63 of the unnecessary object detection unit 60. The mechanical operation is stopped (step S105). Specifically, the control unit 59 controls the operation of the motor control unit 57, for example, thereby conveying the transfer belt 42 in the belt unit 40, conveying the recording medium 9, and the photoreceptor 31 in the image forming unit 30. In addition, the rotation operation of various rollers is stopped. At that time, the control unit 59 lifts the five image forming units 30 and controls the image forming units 30 to be separated from the transfer belt 42. Further, the control unit 59 controls the secondary transfer roller 24 to be lowered so that the secondary transfer roller 24 is separated from the transfer belt 42.

  Next, the display unit 54 displays an error based on an instruction from the control unit 59 (step S106). At that time, the display unit 54 also displays a message prompting the user to clean the transfer belt 42.

  Next, the control unit 59 writes the alarm information INF in the storage unit 40a of the belt unit 40 (step S107).

  Next, the image forming apparatus 1 performs a reverse conveyance operation (step S130). Specifically, the image forming apparatus 1 circulates and conveys the transfer belt 42 in a direction opposite to the conveyance direction F2 (conveyance direction F3).

  FIG. 9 illustrates an example of the backward conveyance operation. In this reverse direction conveyance operation, the image forming apparatus 1 moves the transfer belt 42 in the conveyance direction F2 until the portion of the transfer belt 42 to which the unnecessary material 9b is attached moves, for example, near the five primary transfer rollers 41. Circulate and transport in the opposite direction (transport direction F3). This operation will be described in detail below.

  First, the image forming apparatus 1 starts circulating conveyance of the transfer belt 42 in the conveyance direction F3 (step S131). Specifically, the control unit 59 controls the operation of the motor control unit 57 to circulate and transfer the transfer belt 42 in the transport direction F3.

  10A and 10B show an example of the position of the unnecessary object 9b attached to the transfer belt 42 when the mechanical operation is stopped in step S104. 10A and 10B, the five image forming units 30 and the transfer belt 42 are drawn away from each other, and the secondary transfer roller 24 and the transfer belt 42 are drawn away from each other. In the example of FIG. 10A, the unnecessary object 9 b is located downstream of the line sensor 61 in the conveyance direction F <b> 2 of the transfer belt 42. In the example of FIG. 10B, the unnecessary object 9b is located in the vicinity of the line sensor 61. The image forming apparatus 1 circulates and conveys the transfer belt 42 in the direction opposite to the conveyance direction F2 (conveyance direction F3), thereby moving the unnecessary material 9b attached to the transfer belt 42 shown in FIGS. 10A and 10B. .

  Next, the control unit 59 confirms whether or not the transfer belt 42 has been conveyed by a predetermined distance D1 (step S132). The predetermined distance D1 is, for example, along the conveyance path (FIGS. 10A and 10B) of the transfer belt 42, from the line sensor 61 via the secondary transfer unit 25 and idle rollers 45 and 44, and five primary distances. The distance up to the vicinity of the furthest primary transfer roller 41Y among the transfer rollers 41 can be set. If the transfer belt 42 has been conveyed by a predetermined distance D1 or more (“Y” in step S132), the process proceeds to step S137.

  In step S132, when the transfer belt 42 has not yet been conveyed by the predetermined distance D1 (“N” in step S132), the unwanted object detection unit 60 uses the line sensor 61 to capture an image (captured image P4). Obtain (step S133).

  Next, the image analysis unit 62 of the unnecessary object detection unit 60 removes the image of the region W where the toner image is arranged from the captured image P2 as in step S103 (FIG. 5A) (step S134). The image analysis unit 62 obtains an analysis image P5 by removing the image of the region W from the captured image P4.

  And the determination part 63 detects the front-end | tip of the unnecessary thing 9b based on this analysis image P5 (step S135). In the example of FIG. 10A, the determination part 63 can detect the front-end | tip of the unnecessary thing 9b by the unnecessary thing 9b being conveyed in the conveyance direction F3. On the other hand, in the example of FIG. 10B, since there is an unnecessary object 9b in the vicinity of the line sensor 61, the determination unit 63 can detect the presence of the unnecessary object 9b, but cannot detect the tip of the unnecessary object 9b.

  In step S135, when the leading end of the unwanted object 9b is detected (“Y” in step S135), the control unit 59 controls the operation of the motor control unit 57 to move the transfer belt 42 to the predetermined distance D2. (Step S136). The predetermined distance D2 is, for example, along the conveyance path (FIGS. 10A and 10B) of the transfer belt 42, from the line sensor 61 via the secondary transfer unit 25 and the idle rollers 45 and 44, and five primary distances. The distance up to the vicinity of the central primary transfer roller 41C in the transfer roller 41 can be set.

  Then, the image forming apparatus 1 stops circulating conveyance of the transfer belt 42 (step S137). Specifically, the control unit 59 controls the operation of the motor control unit 57 to stop the transfer operation of the transfer belt 42 in the belt unit 40.

  11A and 11B show an example of the position of the unwanted material 9b attached to the transfer belt 42 when the circulation and conveyance of the transfer belt 42 in the conveyance direction F3 is stopped. FIG. 11A corresponds to FIG. 10A, and FIG. 11B corresponds to FIG. 10B.

  In the example of FIGS. 10A and 11A, the determination unit 63 detects the leading end of the unnecessary object 9b (step S135), and the image forming apparatus 1 conveys the transfer belt 42 by a predetermined distance D2 (step S136). That is, in this example, the image forming apparatus 1 can accurately specify the position of the unnecessary object 9b, and therefore, in this example, the unnecessary object 9b is transferred to the primary transfer roller 41C by conveying the transfer belt 42 by a predetermined distance D2. Move to nearby.

  In the example of FIGS. 10B and 11B, since the determination unit 63 cannot detect the tip of the unnecessary object 9b in step S135, the image forming apparatus 1 conveys the transfer belt 42 by a predetermined distance D1 (step S132). That is, in this example, since the image forming apparatus 1 cannot accurately specify the position of the unnecessary object 9b, the image forming apparatus 1 conveys the transfer belt 42 by a predetermined distance D1. In this case, the unwanted material 9b moves to the vicinity of the primary transfer roller 41Y.

  Thereafter, the user opens the cover of the image forming apparatus 1 and cleans the transfer belt 42 according to the information displayed on the display unit 54. Specifically, for example, the user removes some or all of the five image forming units 30 and removes the unnecessary material 9b attached to the transfer belt 42. Then, when the cleaning of the transfer belt 42 is completed, the user closes the cover. Then, the user operates the operation unit 53 to input that cleaning is completed.

  Next, as illustrated in FIG. 5B, the control unit 59 confirms whether or not the user has input that cleaning has been completed (step S <b> 111). And the control part 59 repeats this step S111 until it is input that cleaning was completed.

  In step S111, when the user inputs that cleaning has been completed (“Y” in step S111), the control unit 59 controls the operation of the motor control unit 57 to transfer the transfer belt 42 in the transport direction F2. Is started (step S112). Accordingly, the transfer belt 42 is circulated and conveyed in a state where each image forming unit 30 is separated from the transfer belt 42 and the secondary transfer roller 24 is separated from the transfer belt 42.

  Next, the unwanted object detection unit 60 acquires an image (captured image P6) using the line sensor 61 (step S113).

  Next, the unnecessary object detection unit 60 detects whether there is an abnormality based on the captured image P6 (step S114). Specifically, the unnecessary object detection unit 60 compares the pixel value of each pixel in the captured image P6 with a predetermined pixel value, and the pixel value exceeds a predetermined pixel value in a pixel region having a predetermined size. Is determined to be abnormal.

  When the transfer belt 42 is appropriately cleaned by the user, the captured image P4 has a pixel value of almost “0” in the entire region. Therefore, the unnecessary object detection unit 60 determines that there is no abnormality. In addition, when the transfer belt 42 is not properly cleaned, the captured image P4 includes, for example, information about the unnecessary object 9b. Therefore, the unnecessary object detection unit 60 determines that there is an abnormality.

  If there is an abnormality in step S114 (“Y” in step S114), the control unit 59 controls the operation of the motor control unit 57 to stop the circulating conveyance of the transfer belt 42 of the belt unit 40 (step S115). ), The process returns to step S106. As a result, the image forming apparatus 1 prompts the user to clean the transfer belt 42 again.

  In step S114, when there is no abnormality (“N” in step S114), the control unit 59 confirms whether or not the transfer belt 42 has been circulated and conveyed one or more times (step S116). If the transfer belt 42 has not been circulated and conveyed more than once (“N” in step S116), the process returns to step S113.

  In step S116, when the transfer belt 42 is circulated and conveyed one or more times (“Y” in step S116), the control unit 59 controls the operation of the motor control unit 57 to circulate the transfer belt 42 of the belt unit 40. The conveyance is stopped (step S117). Then, the control unit 59 controls the five image forming units 30 to be lowered and controls the secondary transfer roller 24 to be lifted. Thereby, the image forming apparatus 1 can perform a printing operation.

  Next, the display unit 54 cancels the error display based on the instruction from the control unit 59 (step S118).

  Then, the control unit 59 deletes the alarm information INF written in the storage unit 40a of the belt unit 40 (step S119).

  Thus, this flow ends.

  As described above, in the image forming apparatus 1, the line sensor 61 that images the transfer belt 42 is provided downstream of the secondary transfer unit 25 in the transport direction F <b> 2 of the transfer belt 42, and an unnecessary object 9 b adheres to the transfer belt 42. The user is prompted to clean the transfer belt 42. Thereby, in the image forming apparatus 1, the possibility that the belt unit 40 or the image forming unit 30 breaks down can be reduced.

  Further, in the image forming apparatus 1, the image analysis unit 62 specifies the region W where the toner image is arranged based on the image (image P1) indicated by the image data generated by the image processing unit 52, and starts from the captured image P2. The analysis image P3 is obtained by removing the image in the region W. Then, the determination unit 63 determines whether or not there is an unnecessary object 9b based on the analysis image P3. In other words, the image analysis unit 62 determines the region to be processed by the determination unit 63 by masking the region W in the captured image P2 based on the image P1. As a result, the image forming apparatus 1 can reduce the risk of being affected by the toner remaining on the transfer belt 42 when determining the presence or absence of the unnecessary material 9b. As a result, the image forming apparatus 1 can improve the accuracy of detecting the presence / absence of the unnecessary object 9b.

  Further, in the image forming apparatus 1, when an unnecessary object 9b adheres to the transfer belt 42, the transfer belt 42 is conveyed in a direction opposite to the conveyance direction F2 (conveyance direction F3). As a result, in the image forming apparatus 1, the portion of the transfer belt 42 to which the unnecessary material 9 b is attached can be moved close to the five primary transfer rollers 41. As a result, in the image forming apparatus 1, the user can easily clean the transfer belt 42. That is, for example, when the transfer belt 42 is not transported in the transport direction F3, the portion of the transfer belt 42 to which the unnecessary material 9b is attached is located near the line sensor 61 as shown in FIGS. 10A and 10B. For example, the user needs to remove the belt unit 40 from the image forming apparatus and clean the transfer belt 42. On the other hand, in the image forming apparatus 1, the transfer belt 42 is transported in the transport direction F <b> 3, and the portion of the transfer belt 42 to which the unnecessary material 9 b is attached is moved near the five primary transfer rollers 41. That is, in the image forming apparatus 1, the portion of the transfer belt 42 to which the unnecessary material 9 b is attached is moved to a position within a predetermined range that is easy for the user to clean. Thereby, in the image forming apparatus 1, for example, since the user does not need to remove the belt unit 40 from the image forming apparatus 1, the transfer belt 42 can be easily cleaned.

  In the image forming apparatus 1, when the transfer belt 42 is conveyed in the direction opposite to the conveyance direction F2 (conveyance direction F3), the secondary transfer roller 24 and the transfer belt 42 are separated from each other and five image formations are performed. The unit 30 and the transfer belt 42 are separated from each other. As a result, in the image forming apparatus 1, the portion of the transfer belt 42 to which the unnecessary object 9 b adheres does not touch the secondary transfer roller 24 or the photosensitive member 31 of the image forming unit 30. 24 and the possibility of adhering to the photoreceptor 31 of the image forming unit 30 can be reduced. As a result, for example, the trouble of cleaning the secondary transfer roller 24 and the photoconductor 31 can be saved, and the possibility that the belt unit 40 and the image forming unit 30 may break down can be reduced.

[effect]
As described above, in this embodiment, since the line sensor for imaging the transfer belt is provided downstream of the secondary transfer unit in the transfer belt conveyance direction F2, the risk of failure of the image forming apparatus is reduced. Can do.

  In this embodiment, when an unnecessary object adheres to the transfer belt, the transfer belt is conveyed in a direction opposite to the conveying direction F2 (conveying direction F3). Since the portion can be moved to a position where the user can easily clean, the user can easily clean the transfer belt.

  In this embodiment, when the transfer belt is conveyed in the direction opposite to the conveyance direction F2 (conveyance direction F3), the secondary transfer roller and the transfer belt are separated from each other, and the five image forming units and the transfer belt are separated from each other. Since they are separated from each other, it is possible to save the trouble of cleaning the secondary transfer roller and the photosensitive member, and to reduce the possibility that the image forming apparatus breaks down.

[Modification 1-1]
In the above embodiment, when the unnecessary object detection unit 60 detects the unnecessary object 9b, the mechanical operation is stopped (steps S104 and S105), but the present invention is not limited to this. For example, the image formation shown in FIG. Like the apparatus 1A, the cutting unit 14 may further cut the recording medium 9 based on an instruction from the control unit 59 (step S145). Thus, for example, when the transfer belt 42 is circulated and conveyed in the direction opposite to the conveyance direction F2 (conveyance direction F3) in step S130, the unnecessary material 9b (label residue) is peeled off from the recording medium 9 and the transfer belt 42 is transferred. Even if it adheres further, the length of the adhering unwanted matter 9b can be shortened.

[Modification 1-2]
In the above embodiment, the cutting unit 14 is provided. However, the present invention is not limited to this. For example, as in the image forming apparatus 1B illustrated in FIG. 13, the cutting unit 14 is provided between the cutting unit 14 and the secondary transfer unit 25. Further, another cutting portion 29B may be provided. This cutting unit 29B is based on an instruction from the control unit 59B according to the present modification when the unnecessary object detection unit 60 detects the unnecessary object 9b, for example, similarly to the image forming apparatus 1A (FIG. 12). The recording medium 9 is cut. As a result, when the transfer belt 42 is circulated and conveyed in the direction opposite to the conveyance direction F2 (conveyance direction F3) in step S130, the unnecessary material 9b (label residue) is peeled off from the recording medium 9 and further transferred to the transfer belt 42. Even if it adheres, the length of the unnecessary object 9b that adheres can be made shorter than in the case of the image forming apparatus 1A.

<2. Second Embodiment>
Next, the image forming apparatus 2 according to the second embodiment will be described. In the present embodiment, a line sensor that images the transfer belt 42 is provided in addition to the downstream of the secondary transfer unit 25 in the conveyance direction F <b> 2 of the transfer belt 42, also upstream of the secondary transfer unit 25. Note that components that are substantially the same as those of the image forming apparatus 1 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  FIG. 14 illustrates a configuration example of the image forming apparatus 2. The image forming apparatus 2 includes a medium supply unit 10 and an image forming unit 70. The image forming unit 70 includes a line sensor 81. The line sensor 81 has light receiving elements arranged in a row and images the transfer surface of the transfer belt 42. The line sensor 81 is disposed upstream of the secondary transfer unit 25 in the transfer direction F <b> 2 of the transfer belt 42.

  FIG. 15 illustrates an example of a control mechanism in the image forming apparatus 2. The image forming apparatus 2 includes an unnecessary object detection unit 80. As in the case of the unnecessary object detection unit 60 (FIG. 4) according to the first embodiment, the unnecessary object detection unit 80 has an unnecessary object 9b (label waste) on the transfer belt 42 based on the detection result of the line sensor 61. It is to detect whether it is attached or not. The unnecessary object detection unit 80 includes a line sensor 61, a line sensor 81, an image analysis unit 82, and a determination unit 63. The image analysis unit 82 performs image analysis based on an image based on the imaging result of the line sensor 81 (captured image P11) and an image based on the imaging result of the line sensor 61 (captured image P2). That is, the image analysis unit 62 according to the first embodiment includes an image (image P1) indicated by the image data generated by the image processing unit 52 and an image based on the imaging result of the line sensor 61 (captured image P2). Based on the image analysis, the image analysis unit 82 according to the present embodiment is based on the imaging result of the line sensor 81 instead of the image (image P1) indicated by the image data generated by the image processing unit 52. Image analysis is performed using (captured image P11).

  Here, the line sensor 81 corresponds to a specific example of a “second detection unit” in the present invention. The image analysis unit 82, the determination unit 63, and the control unit 59 correspond to a specific example of “control unit” in the present invention.

  FIGS. 16A and 16B show an example of the operation of the image forming apparatus 2 when the unnecessary object 9b is detected. The image forming apparatus 2 detects the presence / absence of an unnecessary object 9b (steps S102, S202, S203, and S104 shown in FIG. 16A), the reverse conveyance operation (step S230 shown in FIG. 16A), and the presence / absence of an abnormality. The detected operation (steps S113, S213, and S214 shown in FIG. 16B) is different from the operation (FIGS. 5A and 5B) in the image forming apparatus 1.

  First, the control unit 59 confirms whether or not the image forming apparatus 1 is printing (step S101). If printing is in progress (“Y” in step S101), the unwanted object detection unit 80 As in the case of the first embodiment, an image (captured image P2) is acquired using the line sensor 61 (step S102).

  Next, the unnecessary object detection unit 80 acquires an image (captured image P11) using the line sensor 81 (step S202). This captured image P11 shows the transfer belt 42 before the secondary transfer is performed, and corresponds to the image P1 (FIG. 6) in the first embodiment. In this example, for convenience of explanation, as shown in steps S102 and S202, the captured image P11 is acquired after the captured image P2 is acquired. However, the present invention is not limited to this. Thus, for example, these operations can be performed in parallel.

  Next, the image analysis unit 82 of the unnecessary object detection unit 80 removes the image of the region W where the toner image is arranged from the captured image P2 (step S203). Specifically, the image analysis unit 82 first specifies the region W where the toner image is arranged based on the captured image P11. Then, the image analysis unit 82 obtains the analysis image P3 by removing the image of the region W from the captured image P2.

  Then, as in the case of the first embodiment, the determination unit 63 determines whether there is an unnecessary object 9b based on the analysis image P3 (step S104). If there is no unnecessary object 9b ("N" in step S104), the process returns to step S101.

  In step S104, when there is an unnecessary object 9b (“Y” in step S104), the control unit 59 instructs from the determination unit 63 of the unnecessary object detection unit 80 as in the case of the first embodiment. Based on the above, the mechanical operation of the image forming apparatus 1 is stopped (step S105). At that time, the control unit 59 lifts the five image forming units 30 and controls the image forming units 30 to be separated from the transfer belt 42. Further, the control unit 59 controls the secondary transfer roller 24 to be lowered so that the secondary transfer roller 24 is separated from the transfer belt 42. Then, the display unit 54 displays an error based on an instruction from the control unit 59 (step S106), and the control unit 59 writes the alarm information INF in the storage unit 40a of the belt unit 40 (step S107).

  Next, the image forming apparatus 2 performs a reverse conveyance operation (step S230).

  FIG. 17 illustrates an example of the backward conveyance operation. First, the image forming apparatus 2 starts circulating conveyance of the transfer belt 42 in the conveyance direction F3 (step S131). Next, the control unit 59 determines whether or not the transfer belt 42 has been conveyed by a predetermined distance D1. Confirmation (step S132). If the transfer belt 42 has been conveyed by a predetermined distance D1 or more (“Y” in step S132), the process proceeds to step S137.

  In step S132, when the transfer belt 42 has not yet been conveyed by the predetermined distance D1 (“N” in step S132), the unwanted object detection unit 80 uses the line sensor 61 to capture an image (captured image P4). Obtaining (step S133), an image (captured image P14) is obtained using the line sensor 81 (step S233). These operations can be performed in parallel.

  Next, the image analysis unit 82 of the unnecessary object detection unit 80 removes the image of the region W where the toner image is arranged from the captured images P4 and P14 (step S234). Specifically, the image analysis unit 82 first specifies the region W where the toner image is arranged based on the image (image P1) indicated by the image data generated by the image processing unit 52. Then, the image analysis unit 82 obtains the analysis image P5 by removing the image of the region W from the captured image P4, and obtains the analysis image P15 by removing the image of the region W from the captured image P14. .

  And the determination part 63 detects the front-end | tip of the unwanted object 9b based on this analysis image P5, P15 (step S235). In the example of FIG. 10A, the determination unit 63 can detect the tip of the unnecessary object 9b based on both of the analysis images P5 and P15. Moreover, the determination part 63 can detect the front-end | tip of the unwanted object 9b based on the analysis image P15 in the example of FIG. 10B.

  In step S135, when the leading end of the unwanted object 9b is detected (“Y” in step S135), the control unit 59 controls the operation of the motor control unit 57 to move the transfer belt 42 to the predetermined distance D2. (Step S136). Then, the image forming apparatus 2 stops circulating conveyance of the transfer belt 42 (step S137). As a result, the unwanted material 9b moves, for example, to the vicinity of the primary transfer roller 41C as shown in FIG. 11A.

  Thereafter, the user opens the cover of the image forming apparatus 2 and cleans the transfer belt 42 according to the information displayed on the display unit 54. Specifically, for example, the user removes some or all of the five image forming units 30 and removes the unnecessary material 9b attached to the transfer belt 42. Then, when the cleaning of the transfer belt 42 is completed, the user closes the cover. Then, the user operates the operation unit 53 to input that cleaning is completed. When the user inputs that cleaning has been completed (“Y” in step S111), the control unit 59 controls the operation of the motor control unit 57 to circulate and convey the transfer belt 42 in the conveyance direction F2. Start (step S112).

  Next, the unnecessary object detection unit 80 acquires an image (captured image P6) using the line sensor 61 (step S113), and acquires an image (captured image P16) using the line sensor 81 (step S213). These operations can be performed in parallel.

  Next, the unnecessary object detection unit 80 detects whether there is an abnormality based on the captured images P6 and P16 (step S214). Specifically, the unwanted object detection unit 80 compares the pixel value of each pixel in each of the captured images P6 and P16 with a predetermined pixel value, and the pixel value is a predetermined pixel in a pixel region having a predetermined size. When the value is exceeded, it is determined that there is an abnormality.

  When the transfer belt 42 is appropriately cleaned by the user, the pixel values of the captured images P6 and P16 are substantially “0” in the entire region. Therefore, the unnecessary object detection unit 80 determines that there is no abnormality. In addition, when the transfer belt 42 is not properly cleaned, the captured images P6 and P16 include, for example, information about the unnecessary object 9b. Therefore, the unnecessary object detection unit 80 determines that there is an abnormality.

  If there is an abnormality in step S214 (“Y” in step S214), the control unit 59 controls the operation of the motor control unit 57 in the same manner as in the first embodiment, and the belt unit 40 Circulation conveyance of the transfer belt 42 is stopped (step S115), and the process returns to step S106. As a result, the image forming apparatus 2 prompts the user to clean the transfer belt 42 again.

  If there is no abnormality in step S214 (“N” in step S214), the control unit 59 confirms whether or not the transfer belt 42 has been circulated and conveyed one or more times (step S116). If the transfer belt 42 has not been circulated and conveyed more than once (“N” in step S116), the process returns to step S113.

  The subsequent operation is the same as in the case of the first embodiment (FIGS. 5A and 5B).

  As described above, in the image forming apparatus 2, the line sensor 81 that images the transfer belt 42 is provided upstream of the secondary transfer unit 25 in the conveyance direction F <b> 2 of the transfer belt 42, and the image analysis unit 82 captures the image of the line sensor 81. Based on the image (captured image P11) based on the result, the region W where the toner image is arranged is specified, and the image of the region W is removed from the captured image P2, thereby obtaining the analysis image P3. That is, in the first embodiment, the region W where the toner image is arranged is specified based on the image (image P1) indicated by the image data generated by the image processing unit 52. In the present embodiment, the line W Based on the image (captured image P11) based on the imaging result of the sensor 81, the region W where the toner image is arranged is specified. As described above, in the image forming apparatus 2, the region W where the toner image is arranged is specified based on the toner image actually formed on the transfer belt 42. Thereby, in the image forming apparatus 2, for example, the inclination of the toner image on the transfer belt 42, the shift of the image forming position, the color shift, and the like due to the shift of the mounting position of the exposure unit 39, the image forming unit 30, and the belt unit 40. In consideration of the above, the region W can be specified. As a result, the image forming apparatus 2 can improve the accuracy of detecting the presence or absence of the unnecessary object 9b.

  The image forming apparatus 2 detects the tip of the unwanted object 9b based on the captured image P14 acquired using the line sensor 81 in steps S133, S233 to S235 (FIG. 17). As a result, the image forming apparatus 2 can detect the leading end of the unwanted object 9b in either of FIGS. 10A and 10B, for example, and therefore the unwanted object 9b after the transfer belt 42 is conveyed in the conveyance direction F3. Can be set more accurately.

  As described above, in this embodiment, a line sensor that images the transfer belt is provided upstream of the secondary transfer unit in the transfer belt conveyance direction F2, and a toner image is arranged based on the imaging result of the line sensor. Therefore, the accuracy of detecting the presence or absence of an unnecessary object can be improved.

  A line sensor for imaging the transfer belt is provided upstream of the secondary transfer unit in the transfer belt conveyance direction F2, and the leading edge of the unnecessary object is detected based on the imaging result of the line sensor. It is possible to set the position of the unwanted object after being conveyed in the conveyance direction F3 more accurately.

  Other effects are the same as in the case of the first embodiment.

[Modification 2-1]
Similarly to the modified example 1-1 of the first embodiment, the cutting unit 14 may cut the recording medium 9 when the unwanted matter detection unit 80 detects the unwanted matter 9b (step S104).

[Modification 2-2]
Similarly to the modified example 1-2 of the first embodiment, another cutting unit 29B is provided between the cutting unit 14 and the secondary transfer unit 25 as in the image forming apparatus 2B shown in FIG. It may be provided.

[Modification 2-3]
In the above embodiment, for example, as shown in steps S133, S233 to S235 (FIG. 17), the tip of the unwanted object 9b is detected based on the detection results of the line sensors 61 and 81. However, the present invention is not limited to this. It is not a thing. Instead of this, for example, the tip of the unwanted object 9b may be detected based on the detection result of the line sensor 81.

[Modification 2-4]
In the above embodiment, for example, as shown in steps S113, S213, and S214 (FIG. 16B), the presence or absence of abnormality is detected based on the detection results of the line sensors 61 and 81. However, the present invention is not limited to this. Absent. Instead of this, for example, the presence or absence of an abnormality may be detected based on the detection result of the line sensor 81, or the presence or absence of an abnormality may be detected based on the detection result of the line sensor 61.

  The present technology has been described above with some embodiments and modifications. However, the present technology is not limited to these embodiments and the like, and various modifications are possible.

  For example, in each of the embodiments described above, five image forming units 30 are provided. However, the present invention is not limited to this, and four or less image forming units 30 may be provided, or six or more image forming units 30 may be provided. An image forming unit 30 may be provided. In addition, the plurality of image forming units 30 formed toner images of different colors. However, the present invention is not limited to this, and some or all of the plurality of image forming units 30 may have the same color toner image. May be formed.

  Further, for example, in each of the above-described embodiments, the label residue attached to the transfer belt 42 is detected. However, the present invention is not limited to this. For example, the label 9a attached to the transfer belt 42 or a piece of paper is used. Various things that should not adhere to the transfer belt 42 may be detected.

  Further, for example, in each of the above-described embodiments, as shown in FIG. 2, the recording medium 9 including the label 9a and the label residue around the label 9a is used. However, the present invention is not limited to this. Instead of this, for example, a recording medium from which the label residue has been removed may be used. Even in this case, for example, when the label 9a adheres to the transfer belt 42, the risk of the image forming apparatus failing can be reduced by detecting the label 9a.

  For example, in each of the above-described embodiments, the unnecessary material 9b attached to the transfer belt 42 is detected during printing. However, the present invention is not limited to this. Instead of this, for example, when the recording medium 9 is transported without printing, the unnecessary material 9b attached to the transfer belt 42 may be detected.

  DESCRIPTION OF SYMBOLS 1,1A, 1B, 2,2B ... Image forming apparatus, 8 ... Conveyance path, 9 ... Recording medium, 9a ... Label, 9b ... Unnecessary thing, 9c ... Mount, 9d ... Marker, 10 ... Medium supply part, 11 ... Medium Fixing part, 12 ... conveying roller, 13 ... label sensor, 14 ... cutting part, 20, 70 ... image forming part, 21,22 ... conveying roller, 23 ... label sensor, 24 ... secondary transfer roller, 25 ... secondary transfer 26, fixing unit, 26a ... heat roller, 26b ... pressure roller, 27 ... discharge roller, 29B ... cutting unit, 30, 30Y, 30M, 30C, 30K, 30W ... image forming unit, 31 ... photoconductor, 32 ... Cleaning blade, 33 ... Charging roller, 34 ... Developing roller, 35 ... Developing blade, 36 ... Supply roller, 37 ... Toner storage unit, 39, 39Y, 39M, 39C, 39K, 39W ... Exposure unit, 40 ... 40a ... storage unit, 41, 41Y, 41M, 41C, 41K, 41W ... primary transfer roller, 42 ... transfer belt, 43 ... drive roller, 44, 45 ... idle roller, 46 ... secondary transfer backup roller, 47 ... idle roller 48 ... cleaning device 51 ... communication unit 52 ... image processing unit 53 ... operation unit 54 ... display unit 55 ... exposure control unit 56 ... voltage generation unit 57 ... motor control unit 58 ... Fixing control unit, 59 ... Control unit, 60,80 ... Unnecessary matter detection unit, 61 ... Line sensor, 62,82 ... Image analysis unit, 63 ... Determination unit, 81 ... Line sensor, F1-F3 ... Conveying direction, INF ... alarm information, P1 ... image, P2 ... captured image, P3 ... analyzed image, P4 ... captured image, P6 ... analyzed image, P11 ... captured image, P15 ... analyzed image, 16 ... the captured image.

Claims (15)

A transport unit that carries the developer image, and transports the developer image by circulating and transporting the transport member in the first transport direction;
A transfer member disposed at a predetermined position so as to face the transport member, and transferring the developer image carried on the transport member to a recording medium;
A first detection unit that is disposed downstream of the predetermined position in the first transport direction of the transport member, and detects a deposit attached to the transport member;
Based on the first detection result by the first detection unit when the transport unit is transporting the transport member in the first transport direction, the transport member is transported in the second transport direction. An image forming apparatus comprising: a control unit. The image forming apparatus according to claim 1, wherein the control unit further moves the transport member and the transfer member away from each other based on the first detection result. A second detection unit that is disposed upstream of the predetermined position in the first transport direction of the transport member, and detects a deposit attached to the transport member;
The control unit is configured to move in the second transport direction based on a second detection result by the second detection unit when the transport unit transports the transport member in the second transport direction. The image forming apparatus according to claim 1, wherein conveyance of the conveyance member is stopped. The image forming apparatus according to claim 3, wherein the control unit stops transport of the transport member after transporting the transport member by a predetermined distance in the second transport direction based on the second detection result. apparatus. The control unit is based on a third detection result by the second detection unit and the first detection result when the transport unit is transporting the transport member in the first transport direction. The image forming apparatus according to claim 3, wherein the transport member is transported in the second transport direction. The control unit stops transport of the transport member after transporting the transport member by a predetermined distance in the second transport direction based on the first detection result. The image forming apparatus described. A developing unit that generates the developer image based on image data;
The image forming apparatus according to claim 6, wherein the control unit conveys the conveyance member in the second conveyance direction based on the first detection result and the image data. The said control part makes the said conveyance member convey in the said 2nd conveyance direction, when the deposits other than the developer to the said conveyance member are detected based on the said 1st detection result. Item 8. The image forming apparatus according to any one of Items 7 to 9. The image forming apparatus according to claim 8, wherein the control unit stops the conveyance of the conveyance member in the second conveyance direction so that the attached matter is within a predetermined range in the conveyance path of the conveyance member. A developing unit for generating the developer image;
The image forming apparatus according to any one of claims 1 to 9, wherein the control unit further moves the transport member and the developing unit away from each other based on the first detection result. The image formation according to any one of claims 1 to 10, further comprising a first cutting unit that is provided in a medium conveyance path that conveys the recording medium to the transfer member and is capable of cutting the recording medium. apparatus. The image forming apparatus according to claim 11, wherein the control unit further causes the first cutting unit to cut the recording medium based on the first detection result. A second cutting part provided between the transfer member and the first cutting part and capable of cutting the recording medium;
The image forming apparatus according to claim 11, wherein the control unit further causes the second cutting unit to cut the recording medium based on the first detection result. The image forming apparatus according to claim 1, wherein the conveying member is a belt. The image forming apparatus according to claim 1, wherein the first detection unit is a line sensor.

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