JP2013049525A - Detection device, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a medium that cannot be detected by a sensor for detecting both side parts of the medium conveyed on a conveyance path.SOLUTION: This detection device includes: a light emitting part emitting light crossing at a predetermined position on a conveyance path for conveying a sheet-like medium from one side of the conveyance path; and a light receiving part receiving the light from the light emitting part at the other side. The detection device detects whether at least a portion of the medium is present on the conveyance path on the basis of a light receiving amount obtained by receiving the light emitted from the light emitting part by the light receiving part before the conveyance of the medium is started.

Description

  The present invention relates to a detection device, a fixing device, and an image forming apparatus.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for detecting an abnormal conveyance of a continuous sheet in a sheet conveyance path using an optical sensor. In this technique, a pair of skew detection sensors each composed of a transmissive optical sensor are provided on both sides in the width direction of the continuous paper on the upstream side of the image station 12K on the paper transport path, and the edges in the width direction of the continuous paper are provided. Each edge portion is detected to detect the behavior of the continuous paper conveyed during printing.

JP 2009-078886

  SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus that can detect a medium that cannot be detected by a sensor that detects both sides in the width direction of the medium conveyed on the conveyance path.

  The detection device according to claim 1 of the present invention provides a first light emitting unit that emits light that intersects the conveyance path at one position of the conveyance path where the sheet-like medium is conveyed from one side of the conveyance path. And a first light-receiving unit that receives light emitted from the first light-emitting unit on the other side of the conveyance path, and a light reception amount received by the first light-receiving unit, And a detection unit that detects whether or not at least a part of the medium is present at the first position.

  A detection device according to claim 2 of the present invention is the detection device according to claim 1, wherein light that crosses the conveyance path at a second position within a predetermined range from the first position is transmitted to one side of the conveyance path. A second light-emitting unit that emits light emitted from the second light-emitting unit and a second light-receiving unit that receives light emitted from the second light-emitting unit on the other side of the conveyance path, and the detection unit includes the first light-receiving unit. And at least a part of the medium is detected in the predetermined range of the transport path based on the amount of light received by the second light receiving unit and the second light receiving unit.

  The detection device according to claim 3 of the present invention is the above-described detection device, wherein when the fragment of the recording medium is in the predetermined range, the storage unit is configured to move the fragment downward from the conveyance path and store the fragment. And the detection unit does not detect the medium at the first position and the second position based on the amounts of received light received by the first light receiving unit and the second light receiving unit. Further, it is considered that at least a part of the medium does not exist within the predetermined range.

  According to a fourth aspect of the present invention, there is provided a fixing device according to any one of the first to third aspects, and a position to be detected by the detection device with respect to the medium onto which the toner image is transferred. And a fixing unit for fixing the toner image by irradiating light.

  An image forming apparatus according to a fifth aspect of the present invention includes a transfer unit that transfers a toner image onto a medium, and the fixing device according to a fourth aspect.

  According to the first aspect of the present invention, it is possible to detect a medium that cannot be detected by a sensor that detects both sides of the medium conveyed on the conveyance path.

  According to the invention which concerns on Claim 2, it can be detected whether a medium exists in the predetermined range on a conveyance path.

  According to the third aspect of the present invention, a medium piece that is not transported can be removed from a predetermined range on the transport path.

  According to the fourth aspect of the present invention, it is possible to detect whether or not the medium exists at a position where light for fixing the toner image to the medium is irradiated.

  According to the fifth aspect of the present invention, it is possible to detect whether or not the medium exists at a position where light for fixing the toner image to the recording medium is irradiated.

1 is a block diagram illustrating a configuration of an image forming apparatus according to a first embodiment. 1 is a schematic diagram illustrating a configuration example of an image forming apparatus according to Embodiment 1. FIG. FIG. 3 is a schematic diagram illustrating a fixing unit and a light emitting / receiving unit according to the first embodiment. 2 is a functional block diagram of a control unit according to Embodiment 1. FIG. 3 is an operation flow illustrating an operation example of the image forming apparatus according to the first embodiment. 6 is a diagram illustrating a state of continuous paper in the operation example of Embodiment 1. FIG. FIG. 6 is a schematic diagram illustrating a configuration example of an image forming apparatus according to a second embodiment. FIG. 6 is a schematic diagram illustrating a configuration example of a fixing unit and a light emitting / receiving unit according to a second embodiment. 6 is a diagram illustrating a state of continuous paper in Embodiment 2. FIG. (A) is the figure which illustrated the optical path of the light in the modification 2. FIG. (B) is a figure which illustrated the optical path of the light in the modification 4. FIG.

<Overview>
The detection device, the fixing device, and the image forming apparatus according to the present invention detect whether or not at least a part of the recording medium exists on the conveyance path. The details will be described below by taking the image forming apparatus as an example.

<Embodiment 1>
(Constitution)
FIG. 1 is a block diagram illustrating a configuration example of an image forming apparatus according to the present embodiment. The image forming apparatus 10 is, for example, a sheet-like recording medium (hereinafter referred to as continuous paper) having a perforation for each predetermined length in the longitudinal direction as an example of the medium according to the present invention. ) To form an image by electrophotography. The image forming apparatus 10 includes a control unit 11, an image transfer unit 12, a fixing unit 13, a light emitting / receiving unit 14, a UI (User Interface) unit 15, and a storage unit 16.

  The control unit 11 includes a CPU (Central Processing Unit) and a memory including a ROM (Read Only Memory) and a RAM (Random Access Memory). The CPU controls each unit connected to the control unit 11 by executing a control program stored in the ROM. Specifically, the control unit 11 performs conveyance control for conveying the continuous paper to the image transfer unit 12 and the fixing unit 13, and uses the toner image based on the image data instructed via the UI unit 15 on the continuous paper. The image transfer unit 12 is caused to perform a transfer process for transferring. In addition, the light emitting / receiving unit 14 detects the presence or absence of the continuous paper P at the position irradiated with light by the fixing unit 13 and performs processing according to the detection result. Details of this processing will be described later.

  The image transfer unit 12 is an example of a transfer unit according to the present invention. Under the control of the control unit 11, the image transfer unit 12 performs a transfer process of transferring a toner image based on the instructed image data onto the continuous paper conveyed to the image transfer unit 12. Here, the configuration of the image transfer unit 12 will be described with reference to FIG. FIG. 2 is a schematic diagram illustrating the image forming apparatus 10 according to the present embodiment. As shown in FIG. 2, the image forming apparatus 10 is provided with a plurality of rollers 201, 202, 203, 204, and 205 that convey the continuous paper P. Under the control of the control unit 11, the roller 202 rotates in the direction of the arrow in the drawing to convey the continuous paper P supplied from the paper supply source toward image forming units 12Y, 12M, 12C, and 12K described later. In addition, the roller 201 provided on the upstream side in the transport direction from the roller 202 rotates in the direction of the arrow in the figure under the control of the control unit 11, thereby applying a force in the direction opposite to the transport direction of the continuous paper P. Give to P. The rollers 203, 204, and 205 rotate following the conveyance of the continuous paper P. The continuous paper P is transported in the direction of the arrow (the negative direction of the X axis in the figure) with tension applied by the rotation of these rollers. The image transfer unit 12 uses the image forming units 12Y, 12M, 12C, and 12K including the photoreceptors 120 corresponding to the respective colors (yellow (Y), magenta (M), cyan (C), and black (K)) to form a color image. Is formed on the continuous paper P. Since the configuration of the image forming units 12Y, 12M, 12C, and 12K is common, the configuration of the image forming unit will be specifically described by taking the image forming unit 12Y as an example.

  The image forming unit 12Y includes a photoreceptor 120, a charging device 121, an exposure device 122, a developing device 123, a transfer device 124, and a cleaning device 125. The photoconductor 120 is formed of a cylindrical member having a photoconductive film formed on the surface thereof, holds an electrostatic latent image formed by exposure of the surface, and drives the shaft (Y It rotates in the direction of the arrow in the figure centering on (axial direction). The charging device 121 is disposed in contact with the surface of the photoconductor 120, has a charging roll that rotates following the rotation of the photoconductor 120, and applies a voltage to the charging roll by a voltage application unit (not shown). The surface of the body 120 is charged to a certain potential. The exposure device 122 exposes the surface of the photoreceptor 120 according to the image data to form an electrostatic latent image on the surface of the photoreceptor 120. The developing device 123 develops the electrostatic latent image formed on the surface of the photoreceptor 120 with toner as a developer. The transfer device 124 includes a transfer roll disposed in contact with the photoconductor 120, and a toner image formed on the surface of the photoconductor 120 by applying a transfer voltage to the transfer roll by a voltage application unit (not shown). Is transferred to the continuous paper P. The cleaning device 125 is arranged to be pressed against the surface of the photoconductor 120 and removes toner remaining without being transferred on the surface of the photoconductor 120.

  Next, the fixing unit 13 and the light emitting / receiving unit 14 will be described. FIG. 3 is a schematic diagram illustrating the configuration of the fixing unit 13 and the light emitting / receiving unit 14. 3A is a diagram of the fixing unit 13 and the light emitting / receiving unit 14 viewed in the positive direction of the X axis in FIG. 2, and FIG. 3B is a diagram of the light receiving / emitting unit 14 viewed from the positive direction of the Z axis in FIG. (The illustration of the fixing unit 13 is omitted). As shown in FIG. 3A, the fixing unit 13 includes an irradiation unit 131 that irradiates the continuous paper P on which the toner image is formed by the image transfer unit 12 with light and fixes the toner image on the continuous paper P. The irradiation unit 131 converts the laser light source having a plurality of laser light generating elements arranged in the width direction (Y-axis direction) of the continuous paper P and the laser light indicated by the broken line R1 emitted from the laser light source into parallel light, And an optical member that collects light so that the surface of the continuous paper P being conveyed (the surface facing the irradiation unit 131) is in focus. In the present embodiment, the plurality of irradiation units 131 are arranged side by side so that the laser beam is irradiated to the entire width of the continuous paper P. Hereinafter, the part Qx of the conveyance path irradiated with laser light from the fixing unit 13 is referred to as a fixing position. In the present embodiment, the fixing position is an example of a first position according to the present invention. The fixing unit 13 irradiates the continuous paper P conveyed to the fixing position with laser light from each irradiation unit 131. When the continuous paper P on which the toner image is formed is irradiated with laser light, the toner of the toner image melts and the toner is fixed on the continuous paper P.

  As shown in FIGS. 3A and 3B, the light emitting / receiving unit 14 includes a light emitting unit 141 (an example of a first light emitting unit) and a light receiving unit 142 (an example of a first light receiving unit). The light emitting unit 141 and the light receiving unit 142 are disposed on both sides of the conveyance path of the continuous paper P, that is, at each end in the Y-axis direction of the conveyance path. The light emitting unit 141 includes a light source that emits light having a wavelength different from that of the laser light emitted from the irradiation unit 131. The optical path of the light from the light emitting portion 141 is, for example, in advance in the Z-axis direction and the X-axis direction with reference to the fixing position Qx and the fixing position Qx, as shown by the broken line R2 in FIGS. It is set so as to pass through a predetermined range. That is, in a state where the continuous paper P is normally conveyed to the fixing position Qx, the light passing through the fixing position Qx is set so that the optical path is blocked by the edge of the continuous paper P on the light emitting unit 141 side.

  The light receiving unit 142 includes a light receiving element that is provided at a position facing the light emitting unit 141 across the continuous paper P and receives light having the same wavelength as the light from the light emitting unit 141. The light receiving unit 142 receives the light emitted from the light emitting unit 141 and outputs a signal indicating the amount of received light to the control unit 11. In the state where there is no continuous paper P at the fixing position Qx, there is nothing to block the optical path of the light from the light emitting unit 141, so that the light from the light emitting unit 141 is almost received by the light receiving unit 142. On the other hand, when the continuous paper P is present at the fixing position Qx, that is, when the continuous paper P is normally conveyed to the fixing position, or when the continuous paper P that is torn at the fixing position Qx remains. Since the optical path of the light from the light emitting unit 141 is blocked by the paper P, the amount of light received by the light receiving unit 142 is smaller than the state where there is no continuous paper P.

  Returning to FIG. 1, the description will be continued. The UI unit 15 includes a touch panel and keys. The UI unit 15 sends an operation signal indicating the content of the user's operation of the touch panel and keys to the control unit 11, and displays an instructed image on the touch panel under the control of the control unit 11. The storage unit 16 includes a storage medium such as a hard disk, and stores data such as image data used by the image transfer unit 12.

  Next, functions of the control unit 11 will be described. FIG. 4 is a functional block diagram relating to each control of the control unit 11. As shown in FIG. 4, the control unit 11 includes a transfer control unit 110, a fixing control unit 111, and a detection control unit 112. When the detection control unit 112 detects that the continuous paper P does not exist at the fixing position before starting the transfer process, the transfer control unit 110 drives each roller to convey the continuous paper P. The image transfer unit 12 is caused to perform a transfer process. When the conveyance of the continuous paper P is started, the fixing control unit 111 irradiates a laser beam from the fixing unit 13 and fixes the toner image on the continuous paper P on which the toner image conveyed to the fixing position is formed. I do.

  The detection control unit 112 is an example of a detection unit according to the present invention. The detection control unit 112 drives the light receiving and emitting unit 14 before the conveyance of the continuous paper P is started, and based on the amount of light received by the light receiving unit 142, the presence or absence of the continuous paper P at the fixing position, that is, The presence or absence of the continuous paper P at the fixing position is detected. For example, the detection control unit 112 detects whether or not the continuous paper P is present as follows. The detection control unit 112 detects the presence of the continuous paper P at the fixing position when the amount of light received by the light receiving unit 142 is equal to or less than a predetermined threshold, and the amount of received light is determined based on the predetermined threshold. If it is larger, it is detected that there is no continuous paper P at the fixing position. Before the transfer process is started, that is, in a state where the continuous paper P is not conveyed on the conveyance path, the continuous paper P should not exist at the fixing position. However, for example, when a jam occurs during the previous image forming process and the continuous paper P is torn before and after the fixing position, the torn continuous paper P may remain at the fixing position. When the transfer process is resumed in a state where the continuous paper P that should not originally exist before the start of conveyance of the continuous paper P remains at the fixing position, the laser light is irradiated to the continuous paper P remaining at the fixing position. Will be. Therefore, in this embodiment, before the conveyance of the continuous paper P is started, it is detected whether or not there is a continuous paper P that should not originally exist at the fixing position.

(Operation example)
Next, the operation of the image forming apparatus 10 according to the present embodiment will be described. FIG. 5 is a diagram illustrating an operation flow of the image forming apparatus 10. The control unit 11 of the image forming apparatus 10 stands by until receiving an image forming instruction based on the image data designated via the UI unit 15 (step S11: NO), and receives the image forming instruction (step S11: YES), the light emitting unit 141 of the light emitting / receiving unit 14 is caused to emit light, the light emitted from the light emitting unit 141 is received by the light receiving unit 142, and the fixing position is included based on the signal indicating the amount of received light output from the light receiving unit 142 The presence or absence of continuous paper P in the transport path is detected (step S12). For example, as illustrated in FIG. 6, when the torn continuous paper P exists at the fixing position, the light (R2) from the light emitting unit 141 toward the light receiving unit 142 is blocked by the continuous paper P. In this case, the amount of received light received by the light receiving unit 142 is equal to or less than a predetermined threshold value, and the control unit 11 detects that at least a part of the continuous paper P exists at the fixing position (step S12: YES). ). And the control part 11 displays on the touch panel of UI part 15 the information which shows that the continuous paper P exists in a fixing position, and alert | reports (step S13).

  In step S12, if the amount of light received by the light receiving unit 142 is greater than a predetermined threshold value, the control unit 11 detects that the continuous paper P does not exist at the fixing position (step S12: NO). ), The rollers are driven to start transporting the continuous paper P (step S14). Then, the control unit 11 reads the designated image data from the storage unit 16 and forms a toner image based on the image data on the continuous paper P by the image transfer unit 12 (step S15). Further, the control unit 11 drives the fixing unit 13 to irradiate the continuous paper P which has been transferred and transported to the fixing position by irradiating the continuous paper P with a laser beam, thereby fixing the toner image on the continuous paper P (step S16). .

  In the first embodiment described above, the continuous paper P is detected even when there is a fragment of the continuous paper P having a width smaller than the width of the continuous paper P at the fixing position. In addition, before the continuous paper P is transported, that is, in a situation where the continuous paper P is not originally transported on the transport path, if the continuous paper P fragments remain at the fixing position, the transport of the continuous paper P is not performed. No laser light is irradiated without being performed. For this reason, a situation in which the continuous paper P is not properly conveyed or fixed due to a fragment of the continuous paper P remaining at the fixing position is avoided.

<Embodiment 2>
FIG. 7 is a schematic diagram illustrating the configuration of the image forming apparatus 10 according to the present embodiment. In this figure, the components common to the first embodiment are denoted by the reference numerals of the components. In the present embodiment, a light emitting / receiving unit 140 having a configuration different from that of the light receiving / emitting unit 14 of the first embodiment is provided. Here, the schematic diagram showing the structure of the light emitting / receiving unit 140 is shown in FIG. As shown in FIG. 8A, in the transport path Q of the continuous paper P, members 143 (143a, 143b) that allow the continuous paper P to pass are provided apart from the upstream side and the downstream side from the fixing position Qx. A container 144 that stores the torn continuous paper P is provided between the member 143a and the member 143b on the back side of the continuous paper P. The members 143a and 143b are made of, for example, a sheet metal having a width equivalent to the width of the continuous paper P, and each end of the sheet metal provided on the front side and the back side of the continuous paper P on the fixing unit 13 side is continuous paper P. It is formed by being bent in a direction away from the conveyance path. The bent end of the back side of the continuous paper P is joined to the upper end of the container 144. When the conveyance of the continuous paper P is started, the continuous paper P passes through the roller 204 and then passes through the member 143a to reach the fixing position. Then, it passes through the member 143b and moves toward the roller 205. Further, the continuous paper P is torn during the conveyance, and a piece of the continuous paper P (hereinafter referred to as a paper piece) less than the length between the members 143a and 143b stays in the member 143a, and the new continuous paper P is conveyed. When the sheet piece is pushed out by the above, the sheet piece falls downward without being straddled across the members 143a and 143b and is accommodated in the container 144.

  In addition, the member 143 and the container 144 are an example of the accommodating part which concerns on this invention. As shown in FIG. 8B (the light receiving portions 142a and 142b are not shown), the accommodating portion is located at a distance between the upstream end X1 and the downstream end X2 in a predetermined region including the fixing position Qx. Any configuration may be used as long as the piece of continuous paper P having a length less than the fixed position is moved below the fixing position, that is, moved away from the focus of the irradiated laser beam. For example, a sheet metal having a width equivalent to the width of the continuous paper P is provided on the back surface side of the continuous paper P, and a portion of the sheet metal corresponding to a predetermined region is recessed below the fixing position to form an accommodating portion. May be.

  Further, between the member 143a and the member 143b, that is, at each end portion in the Y-axis direction of the conveyance path Q at the end portion of the member 143a and the member 143b on the fixing unit 13 side, is common to the light emitting and receiving unit 14 of the first embodiment. The first light emitting / receiving unit 14A and the second light emitting / receiving unit 14B having the structure are supported. The first light emitting / receiving unit 14A includes a first light emitting unit 141a and a first light receiving unit 142a, and the second light receiving / emitting unit 14B includes a second light emitting unit 142a and a second light receiving unit 142b. . As shown in FIG. 8C, the optical path is set so that the light R2 from the first light emitting unit 141a passes through the upstream end X1 of the predetermined region including the fixing position Qx in the transport path Q. The optical path is set so that the light R2 from the second light emitting unit 142a passes through the downstream end X2 of the region. In the present embodiment, the upstream end X1 of the predetermined region is an example of the first position according to the present invention, and the downstream end X2 is an example of the second position according to the present invention. The predetermined area is an example of a predetermined range from the first position according to the present invention.

  The detection control unit 112 of the control unit 11 controls the first light receiving and emitting unit 14A and the second light receiving and emitting unit 14B before starting the conveyance of the continuous paper P, and the first light receiving unit 142a and the second light receiving unit 142B. The presence or absence of the continuous paper P straddling the members 143a and 143b or the continuous paper P blocking the optical path of the first light emitting / receiving portion 14A or the second light emitting / receiving portion 14B based on the amount of light received by each light receiving portion 142b. By detecting, it is detected whether or not the continuous paper P exists in a predetermined range including the fixing position. For example, as shown in FIG. 9A, when the continuous paper P exists across the members 143a and 143b, the respective light receiving amounts of the first light receiving unit 142a and the second light receiving unit 142b are equal to or less than a threshold value. In this case, the detection control unit 112 detects that the continuous paper P exists in a predetermined range including the fixing position, and notifies the UI unit 15 that the continuous paper P exists at the fixing position.

  For example, as shown in FIGS. 9B and 9C, the continuous paper P is nipped by the roller 204 or the roller 205 so as to block the optical path of the first light emitting / receiving unit 14A or the second light receiving / emitting unit 14B. When the continuous paper P hangs down, the received light amount of one of the first light receiving unit 142a and the second light receiving unit 142b is equal to or smaller than the threshold value, and the other received light amount is larger than the threshold value. In this case, the detection control unit 112 detects that the continuous paper P exists on the upstream side or downstream side of the fixing position, and detects that the continuous paper P exists on the conveyance path on the upstream side or downstream side of the fixing position. Notification is made via the unit 15.

  In addition, if the continuous paper P does not block the optical paths of the first light receiving / emitting unit 14A and the second light receiving / emitting unit 14B, the amount of light received by each of the first light receiving unit 142a and the second light receiving unit 142b is Is also greater than the threshold. In this case, the detection control unit 112 detects that the continuous paper P does not exist in a predetermined area including the fixing position. The control unit 11 starts conveying the continuous paper P, performs a transfer process on the continuous paper P, and performs a fixing process on the continuous paper P after the transfer process.

  In Embodiment 2 described above, a sheet piece that is less than the length between the members 143a and 143b is accommodated in the container 144 below the conveyance path, so that the sheet piece does not remain at the fixing position. For this reason, even when a sheet that is not conveyed and remains at the fixing position is generated, the possibility of overheating by the fixing light is reduced. In addition, if the continuous paper P remains on the upstream side or the downstream side of the fixing position before the conveyance of the continuous paper P, the specification is often such that the continuous paper P is not conveyed and the transfer process is not performed. . In such a case, the conveyance failure caused by the continuous paper P remaining in the conveyance path upstream or downstream of the fixing position is prevented.

<Modification>
Although the embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and can be implemented in various other forms. For example, the above-described embodiment may be modified as follows to implement the present invention, or may be implemented in combination with each modification. Hereinafter, modifications of the present invention will be described.

(1) In the first embodiment described above, an example of detecting whether or not the continuous paper P exists at the fixing position before the continuous paper P starts to be transported, that is, in a situation where the continuous paper P does not originally exist on the transport path. In the situation where the transfer process is started and the continuous paper P is originally transported to the fixing position, it may be detected whether or not the continuous paper P exists at the fixing position. For example, the control unit 11 starts the transfer process by conveying the continuous paper P, and a predetermined time from when a predetermined time elapses until the leading end of the continuous paper P reaches the fixing position. Each time, the light emitting unit 141 of the light emitting / receiving unit 14 emits light and is received by the light receiving unit 142, and the presence or absence of the continuous paper P at the fixing position is sequentially detected based on the amount of light received by the light receiving unit 142. When the control unit 11 detects that the continuous paper P does not exist, the control unit 11 stops the fixing unit 13 and stops the conveyance and transfer processing of the continuous paper P to indicate that the conveyance of the continuous paper P is abnormal. Information is notified via the UI unit 15.

(2) In the first embodiment described above, an example in which light from the light emitting unit 141 is applied to the fixing position as an example of the first position according to the present invention has been described. For example, as illustrated in FIG. In addition, the light R2 from the light emitting unit 141 may be applied to a part of the fixing position.

(3) In the first or second embodiment described above, before starting the conveyance of the continuous paper P, the presence of the continuous paper P on the conveyance path is confirmed by the method of the first or second embodiment, and the continuous paper P is conveyed. After starting, the image forming apparatus 10 may be configured to check whether or not the continuous paper P is conveyed on the conveyance path by the method shown in the modification (1).

(4) In the above-described second embodiment, the example in which the accommodating portion having the member 143 and the container 144 is provided on the conveyance path has been described. However, even if the accommodation portion is not provided on the conveyance path. Good. In the second embodiment, the light path is set so that the light from the first light-emitting unit 141a and the second light-emitting unit 141b passes through the upstream end X1 and the downstream end X2 of a predetermined region. In this example, as indicated by a broken line R2 in FIG. 10B, the light from the first light emitting unit 141a and the second light emitting unit 141b in a predetermined region on the conveyance path Q. The optical paths may be set so that.

(5) In Embodiment 1 described above, an example in which the first position is the fixing position has been described. However, the first position is not limited to the fixing position as long as it is a predetermined position on the conveyance path. In the above-described second embodiment, the fixing position is included in a predetermined area on the conveyance path. However, the fixing position may not be included in the predetermined area. That is, it may be configured to detect whether or not at least a part of the recording medium exists in the conveyance path upstream or downstream of the fixing unit 13.

(6) In Embodiment 1 or 2 described above, the recording medium in which perforations are formed in advance has been described as an example of continuous paper. However, the recording medium is continuous in the longitudinal direction in which no perforations are formed. Also good. In this case, after the fixing process is performed by the fixing device, a cutting unit for cutting continuous paper may be provided. The medium to be conveyed may be a medium other than continuous paper such as cut paper cut in advance according to the size of the paper.

(7) In the first and second embodiments described above, an example of a fixing device that irradiates a laser beam to fix a toner image on the recording medium has been described. However, the toner is irradiated by irradiating the recording medium with light from a flash lamp that emits flashing light. A fixing device for fixing an image may be used. In this case, the fixing position is an area on the conveyance path to which light from the flash lamp is irradiated.

(8) In the first and second embodiments described above, the image transfer unit 12 may include a so-called rotary developing device in which a plurality of developing devices are provided along the circumferential direction of the rotating body, or a monochrome image. It may be formed.

(9) In the above-described embodiment, the example of the image forming apparatus has been described. However, the toner image is transferred to the recording medium on which the toner image is transferred by the image transfer unit 12 to the fixing device provided on the downstream side of the image transfer unit 12. As the fixing unit 13 to be fixed and the light emitting / receiving unit 14 as the first light emitting unit and the first light receiving unit, or as the first light emitting unit, the first light receiving unit, the second light emitting unit, and the second light receiving unit. The first light emitting / receiving unit 14A and the second light receiving / emitting unit 14B, and the detection control unit 112 as a detection unit may be provided. Further, the detection device provided on the conveyance path includes a first light emitting unit and a light receiving / emitting unit 14 as a first light receiving unit, or a first light emitting unit, a first light receiving unit, a second light emitting unit, and a second light emitting unit. The first light receiving / emitting unit 14A and the second light receiving / emitting unit 14B as the two light receiving units and the detection control unit as the detecting unit may be provided.

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 11 ... Control part, 12 ... Image transfer part, 13 ... Fixing part, 14,140 ... Light receiving / emitting part, 14A ... 1st light receiving / emitting part , 14B: second light emitting / receiving unit, 15 ... UI unit, 16 ... storage unit, 110 ... transfer control unit, 111 ... fixing control unit, 112 ... detection control unit, 131 ... Irradiation unit, 141 ... Light emitting unit, 142 ... Light receiving unit, 142a ... First light receiving unit, 142b ... Second light receiving unit, 143, 143a, 143b ... Member 144, containers 201, 202, 203, 204, 205 ... rollers

Claims (5)

A first light-emitting unit that emits light from one side of the conveyance path at a first position of the conveyance path in which the sheet-like medium is conveyed;
A first light receiving unit that receives light emitted from the first light emitting unit on the other side of the transport path;
A detection unit configured to detect whether at least a part of the medium is present at the first position of the transport path based on the amount of light received by the first light receiving unit. Detection device. A second light-emitting unit that emits light from one side of the conveyance path at a second position within a predetermined range from the first position;
A second light receiving unit that receives light emitted from the second light emitting unit on the other side of the transport path;
The detection unit determines whether or not at least a part of the medium exists in the predetermined range of the conveyance path based on the amounts of received light received by the first light receiving unit and the second light receiving unit. The detection device according to claim 1, wherein When the fragment of the recording medium is in the predetermined range, the container includes a storage unit that stores the fragment by moving the fragment downward from the conveyance path,
When the detection unit does not detect the medium at the first position and the second position based on the amount of received light received by the first light receiving unit and the second light receiving unit, The detection apparatus according to claim 2, wherein at least a part of the medium does not exist within a predetermined range. The detection device according to any one of claims 1 to 3,
A fixing device comprising: a fixing unit that fixes the toner image by irradiating the medium onto which the toner image has been transferred with light at a position to be detected by the detection device. A transfer portion for transferring a toner image to a medium;
An image forming apparatus comprising: the fixing device according to claim 4.

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