JP6601252B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, image forming apparatuses such as printers and copiers that employ an electrophotographic method have been widely used. In general image forming apparatuses, the direction of the paper is the direction of conveyance due to various types and properties of the paper used, the characteristics of parts such as the conveyance rollers, and the usage environment of temperature and humidity during conveyance. In some cases, the sheet is transported in a direction that is orthogonal (hereinafter referred to as an axial direction or a main scanning direction). If the printing process is executed in this state, there is a problem that the printing position accuracy is lowered.

  In order to solve this problem, the deviation amount in the width direction of the sheet is detected by a deviation sensor, and the sheet is moved in the main scanning direction while the sheet is sandwiched by a pair of registration rollers based on the detection result. So-called offset correction (registration swing correction) is performed to adjust the positional relationship of the sheets. For example, Patent Document 1 discloses an image forming apparatus that calculates the amount of deviation of a sheet by measuring the edge of the sheet using a line sensor and swings a registration roller in the main scanning direction based on the calculated amount of deviation. Are listed.

JP 2013-88627 A

  However, the conventional image forming apparatus described in Patent Document 1 has the following problems. In a general deviation sensor, the allowable heat-resistant temperature is defined in advance from the viewpoint of sensor detection specifications and durability. However, when the temperature in the space where the offset sensor is placed rises due to the heat of the paper after the fixing process and the temperature rise of the swing motor and transport drive motor due to the increase of the linear speed due to the improvement of productivity There is. In such a case, the temperature of the offset sensor during continuous operation increases due to the temperature rise of the arrangement space, and there is a problem that the detection accuracy and durability of the offset sensor are reduced.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of preventing a temperature increase of a deviation sensor during operation.

  In order to solve the above problems, an image forming apparatus according to the present invention is a roller pair that corrects a deviation of a sheet by moving the sheet in a second direction orthogonal to the first direction of the sheet conveyance direction. And a displacement sensor that is provided downstream of the pair of rollers in the first direction and detects a displacement of the sheet, and a cover member that covers the displacement sensor, the cover member being A hole for discharging heat inside the cover member is provided at a position different from the position where the sensor is arranged.

  According to the present invention, it is possible to prevent an increase in the temperature of the offset sensor in the cover member while preventing contamination of the offset sensor and taking measures against static electricity, thereby ensuring the detection accuracy of the offset sensor.

1 is a diagram illustrating a configuration example of an image forming apparatus according to an embodiment of the present invention. It is a perspective view which shows the structural example of the resist unit which concerns on the 1st Embodiment of this invention. It is a top view which shows the structural example of a resist unit. FIG. 6 is a cross-sectional view illustrating a configuration example of a registration unit when viewed from the sheet conveyance direction side. It is sectional drawing which shows the structural example of the resist unit at the time of seeing from the main scanning direction side. It is a figure which shows the structural example of an image forming unit stand and a resist unit. It is a perspective view which shows the structural example of the resist unit which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the function example of a resist unit. It is a perspective view which shows the structural example of the resist unit which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating the function example of a resist unit. It is a perspective view which shows the structural example of the resist unit which concerns on the 4th Embodiment of this invention. 6 is a flowchart illustrating an operation example of the image forming apparatus during job execution.

  Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the dimension ratio of drawing is expanded on account of description and may differ from an actual ratio.

<First Embodiment>
[Configuration Example of Image Forming Apparatus 100]
FIG. 1 shows an example of the configuration of an image forming apparatus 100 according to the present invention. As shown in FIG. 1, the image forming apparatus 100 is called a tandem type image forming apparatus, and includes an automatic document feeder 80 and an apparatus main body 102. The automatic document conveyance unit 80 is attached to the upper part of the apparatus main body 102 and sends out the paper set on the conveyance table to the image reading unit 90 of the apparatus main body 102 by a conveyance roller or the like.

  The apparatus main body 102 includes an operation display unit 70, an image reading unit 90, an image forming unit 10, an intermediate transfer belt 8, a paper feeding unit 20, a registration unit 200A, a fixing unit 44, and an automatic paper reversing and conveying unit. 60 (Auto Duplex Unit: hereinafter referred to as ADU).

  The operation display unit 70 includes a touch panel in which a display unit and an input unit are combined, and a plurality of operation keys including a start key and a determination key provided in a peripheral part of the touch panel. The operation display unit 70 displays an operation screen or the like on the screen, or receives information such as an image forming condition input by a touch operation on the operation screen or an operation of an operation key.

  The image reading unit 90 scans and exposes the document placed on the document table or the document transported by the automatic document transport unit 80 by the optical system of the scanning exposure device, and the image of the scanned document is CCD (Charge Coupled Device). ) Photoelectric conversion is performed by an image sensor to generate an image information signal. The image information signal is output to the image forming unit 10 after being subjected to analog processing, analog / digital (hereinafter referred to as A / D) conversion processing, pseudo correction, image compression processing, and the like by an image processing unit (not shown).

  The image forming unit 10 forms an image by electrophotography, and includes an image forming unit 10Y that forms a yellow (Y) image, an image forming unit 10M that forms a magenta (M) image, The image forming unit 10C forms a cyan (C) color image, and the image forming unit 10K forms a black (K) color image. In this example, common function names, for example, Y, M, C, and K indicating colors to be formed are added to the back of the reference numeral 10.

  The image forming unit 10Y includes a photosensitive drum 1Y, a charger 2Y, an exposure unit (optical writing unit) 3Y, a developing unit 4Y, and a cleaning unit 6Y arranged around the photosensitive drum 1Y. The image forming unit 10M includes a photosensitive drum 1M, a charger 2M, an exposure unit 3M, a developing unit 4M, and a cleaning unit 6M disposed around the photosensitive drum 1M. The image forming unit 10C includes a photosensitive drum 1C, and a charger 2C, an exposure unit 3C, a developing unit 4C, and a cleaning unit 6C disposed around the photosensitive drum 1C. The image forming unit 10K includes a photosensitive drum 1K, a charger 2K, an exposure unit 3K, a developing unit 4K, and a cleaning unit 6K disposed around the photosensitive drum 1K.

  Respective photosensitive drums (image carriers) 1Y, 1M, 1C, and 1K in the image forming units 10Y, 10M, 10C, and 10K, chargers 2Y, 2M, 2C, and 2K, exposure units 3Y, 3M, 3C, and 3K, development The devices 4Y, 4M, 4C, and 4K, the cleaning units 6Y, 6M, 6C, and 6K, and the primary transfer rollers 7Y, 7M, 7C, and 7K have a common configuration. In the following description, Y, M, C, and K are not used unless particularly distinguished.

  The charger 2 charges the surface of the photosensitive drum 1 almost uniformly. The exposure unit 3 is composed of, for example, an LPH (LED Print Head) having an LED array and an imaging lens, or a polygon mirror type laser exposure scanning device, and the photosensitive drum 1 is irradiated with laser light based on an image information signal. Scan to form an electrostatic latent image. The developing device 4 develops the electrostatic latent image formed on the photosensitive drum 1 with toner. As a result, a toner image which is a visible image is formed on the photosensitive drum 1.

  The intermediate transfer belt 8 is stretched by a plurality of rollers and is rotatably supported. Along with the rotation of the intermediate transfer belt 8, the primary transfer roller 7 and the photosensitive drum 1 rotate, and a predetermined voltage is applied between the primary transfer roller 7 and the photosensitive drum 1, whereby the photosensitive member. The toner image formed on the drum 1 is transferred onto the intermediate transfer belt 8 (primary transfer).

  The paper feed unit 20 has a plurality of paper feed trays 20A and 20B in which paper P such as A3 and A4 is accommodated. The paper P transported from the paper feed trays 20A, 20B by the transport rollers 22, 24, 26, 28, etc. is transported to the registration unit 200A. Note that the number of paper feed trays is not limited to two. Further, a single or a plurality of large-capacity paper feeders that can accommodate a large-capacity paper P may be connected as necessary.

  The sheet P conveyed to the registration unit 200A is abutted against the registration roller pair 210 by the conveyance of the loop roller pair 202, thereby forming a loop and bending the sheet P with respect to the sheet conveyance direction (sub-scanning direction) D1 (for example, slanting). Line) is corrected. The paper P in which the bending of the paper P is corrected is conveyed to the secondary transfer unit 34 at a predetermined timing. In the secondary transfer unit 34, the Y, M, C, and K color toner images transferred onto the intermediate transfer belt 8 are collectively transferred onto the surface of the sheet P conveyed by the resist roller pair 32 (secondary). Next transfer). The second-transferred paper P is conveyed to the fixing unit 44 on the downstream side in the paper conveyance direction D1.

  The fixing unit 44 includes a pressure roller and a heating roller. The fixing unit 44 fixes the toner image on the surface of the paper P to the paper P by performing pressure and heat treatment on the paper P on which the toner image has been transferred by the secondary transfer unit 34.

  The conveyance path switching unit 48 is provided downstream of the fixing unit 44 in the sheet conveyance direction D1, and performs conveyance path switching control based on a selected printing mode (single-sided printing mode, duplex printing mode, or the like). The paper P on which single-sided printing has been completed in the single-sided printing mode or the paper P on which double-sided printing has been completed in the double-sided printing mode is discharged onto the paper discharge tray by the paper discharge roller 46.

  Further, when an image is formed on the back side of the paper P in the duplex printing mode, the paper P on which the image is formed on the front side is conveyed to the ADU 60 via the conveyance roller 62 and the like. In the switchback path of the ADU 60, the reverse rotation control of the ADU roller 64 causes the rear end of the paper P to be transported to the U-turn path section, and is reversed by the transport rollers 66 and 68 provided in the U-turn path section. In this state, the paper is fed again to the secondary transfer unit 34.

[Configuration example of resist unit 200A]
FIG. 2 is a perspective view showing an example of the configuration of the resist unit 200A according to the first embodiment. FIG. 3 is a plan view showing an example of the configuration of the resist unit 200A. FIG. 4 is a cross-sectional view showing an example of the configuration of the registration unit 200A when viewed from the paper transport direction D1. FIG. 5 is a cross-sectional view showing an example of the configuration of the resist unit 200A when viewed from the main scanning direction D2.

  2 to 4, the left side of the paper in the main scanning direction D2 is the front side of the apparatus main body 102 (hereinafter referred to as the front side of the apparatus), and the right side of the paper in the main scanning direction D2 is the back side of the apparatus main body 102 (hereinafter referred to as the apparatus). Called the back side). 3 and 4, the driven roller 214 of the registration roller pair 210 is omitted for convenience. The same applies to FIGS. 7 to 11 shown in the second, third, and fourth embodiments.

  As shown in FIGS. 2 to 5, the registration unit 200 </ b> A includes a registration roller pair 210, a registration roller conveyance drive motor 220, a deviation sensor 250, a cover member 260, and a pair of guide plates 290. .

  The registration roller pair 210 is disposed upstream of the secondary transfer unit 34 in the paper transport direction D1. The registration roller pair 210 includes a driving roller 212 that rotates and a driven roller 214 that rotates following the rotation of the driving roller 212. The registration roller pair 210 corrects the bending of the paper P by creating a loop by abutting the front end of the paper, corrects the alignment of the front end of the paper after the paper re-conveying and the front end of the image, or sandwiches the paper P. The deviation of the paper P is corrected by swinging (moving) in the main scanning direction D2.

  The registration roller conveyance drive motor 220 is composed of, for example, a stepping motor, and is disposed on the front side of the apparatus. In other words, the registration roller conveyance drive motor 220 is arranged on the side from which the registration unit 200A (image forming unit mount 300) is pulled out from the apparatus main body 102. The registration roller transport drive motor 220 is connected to the rotation shaft 213 of the drive roller 212 via the gear 222, and rotates to drive the drive roller 212 to transport the paper P in the paper transport direction D1. In this example, only the registration roller conveyance drive motor 220 is described, but the registration roller pair 210 is swung in the main scanning direction D2 based on the deviation amount of the paper P detected by the deviation sensor 250. It is assumed that the registration roller swing motor and the registration roller press release motor that presses and separates the registration roller pair 210 according to the swing operation of the registration roller pair 210 are also arranged on the front side of the apparatus.

  The deviation sensor 250 is arranged downstream of the registration roller pair 210 in the paper conveyance direction D1, and detects the end position (deviation amount) of the paper P conveyed by the registration roller pair 200. The displacement sensor 250 is formed such that the length in the main scanning direction D2 is shorter than the length in the main scanning direction D2 of the registration roller pair 210, and is arranged close to the registration roller conveyance drive motor 220 side (front side of the apparatus). Yes. As the offset sensor 250, a line sensor in which a plurality of photoelectric conversion elements are linearly arranged along the main scanning direction D2, an image sensor in which photoelectric conversion elements are arranged in a matrix, or the like can be used. As the line sensor and the image sensor, a CCD type image sensor or a CMOS type (including MOS type) image sensor can be used.

  The cover member 260 is a rectangular box extending in the main scanning direction D2 when seen in a plan view, and covers the entire displacement sensor 250. The cover member 260 is formed so that its longitudinal direction is substantially the same as the longitudinal direction of the registration roller pair 210, and one end side of the cover member 260 on the back side (paper center side) in the main scanning direction D2 is offset. The sensor 250 extends further to the back of the apparatus than the end 250a of the back of the apparatus. In this example, a portion extending (extending) from the end portion 250a of the offset sensor 250 of the registration roller pair 210 is referred to as an extending portion 260a. Further, the length of the cover member 260 in the paper transport direction D1 is formed longer than the length of the deviation sensor 250 in the paper transport direction D1. For example, a metal material is used for the cover member 260 in order to prevent the influence of static electricity caused by the user's contact or the like.

  A plurality of heat exhaust holes 262 for exhausting heat inside the cover member 260 to the outside are formed in the upper surface portion of the extending portion 260a of the cover member 260. In other words, the plurality of heat exhaust holes 262 are formed at a position different from the position of the cover member 260 immediately above where the offset sensor 250 is arranged, that is, at an end of the cover member 260 opposite to the offset sensor 250. Has been. Here, the heat includes heat that is transferred from the registration roller conveyance drive motor 220 and the like to the inside of the cover member 260. The plurality of heat exhaust holes 262 are, for example, circular and are arranged in a staggered manner. The opening diameter and the arrangement pitch of the exhaust heat holes 262 are selected so as to minimize leakage of electromagnetic waves to the outside by the offset sensor 250. For example, the opening diameter of the exhaust heat hole 262 is 5 mm. Note that the shape of the heat exhaust hole 262 is not limited to a circular shape, and various shapes such as an elliptical shape and a rectangular shape can be employed. Further, the number and arrangement of the heat exhaust holes 262 are not limited to the number and arrangement of the heat exhaust holes 262 shown in FIG. Furthermore, if it is a position other than the position directly above the deviation sensor 250, for example, an upstream or downstream position of the deviation sensor 250 in the sheet conveyance direction D1, other than the extension part 260a of the cover member 260, a side surface part of the cover member 260. For example, the exhaust heat holes 262 may be formed. In this case, it is more preferable if the position is other than a position below a toner supply port 310 described later.

[Configuration Example of Image Forming Unit Base 300]
FIG. 6 shows an example of the configuration of the image forming unit mount 300 and the like. As shown in the broken line in FIG. 1 and FIG. 6, the photosensitive drum 1, the developing device 4, the intermediate transfer belt 8, and the like are arranged in one image forming unit frame 300. The image forming unit base 300 is configured to be able to be pulled out from the apparatus main body 102 and loaded into the apparatus main body 102 by a sliding operation in the main scanning direction D2 by the user. A toner replenishing port 310 for supplying toner to the developing device 4 is provided above the image forming unit base 300 on the back side of the apparatus. Although not shown, the resist unit 200A and the ADU 60 are arranged on one ADU frame. The ADU gantry is configured such that it can be pulled out from the apparatus main body 102 and loaded into the apparatus main body 102 by a sliding operation in the main scanning direction D2 by the user.

  As described above, according to the first embodiment, since the heat exhaust hole 262 is formed in the extending portion 260a of the cover member 260, the heat in the cover member 260 is released from the heat exhaust hole 262 to the outside. be able to. As a result, even when productivity is increased, the temperature of the displacement sensor 250 in the cover member 260 due to exhaust heat of motors such as the registration roller conveyance drive motor 220, the registration roller swing motor 230, and the registration roller pressure release motor 240, etc. The rise can be prevented. As a result, it is possible to prevent the detection accuracy of the deviation sensor 250 from being lowered and the durability of the deviation sensor 250 from being lowered.

  Further, according to the first embodiment, the heat exhaust hole 262 is formed at the position of the cover member 260 at a position different from the position directly above the offset sensor 250, and the offset sensor 250 and the exhaust heat hole 262 are separated from each other. Therefore, even when the user contacts the cover member 260 when static electricity is generated when the ADU frame is pulled out, the influence of static electricity on the displacement sensor 250 can be minimized. Thereby, damage to the offset sensor 250 can be avoided. Even if toner or the like enters the cover member 260, the heat exhaust hole 262 is not disposed immediately above the displacement sensor 250, and thus the contamination of the displacement sensor 250 can be prevented.

  Moreover, according to 1st Embodiment, the extension part 260a of the cover member 260 can be functioned as a heat radiating duct. Thereby, the heat in the cover member 260 can be discharged more efficiently.

  Furthermore, according to the first embodiment, since the motor such as the registration roller conveyance drive motor 220 is disposed on the front side of the apparatus, which is the drawer side of the registration unit 200A, the motor can be effectively cooled. . Thereby, the temperature rise of the deviation sensor 250 can be reliably suppressed.

<Second Embodiment>
In the second embodiment, the positions of the displacement sensor 250 and the exhaust heat hole 262 are different from those of the first embodiment. Since the other configurations and operations of the image forming apparatus 100 are the same as those in the second embodiment, common constituent elements are denoted by the same reference numerals and detailed description thereof is omitted.

[Configuration example of resist unit 200B]
FIG. 7 is a perspective view showing an example of the configuration of a resist unit 200B according to the second embodiment. As shown in FIG. 7, the registration unit 200 </ b> B includes a registration roller pair 210, a registration roller conveyance drive motor 220, a displacement sensor 250, and a cover member 260.

  The registration roller conveyance drive motor 220 is connected to the end of the rotary shaft 213 on the front side of the drive roller 212 via a gear 222. The deviation sensor 250 is disposed at a position close to the back side of the apparatus opposite to the registration roller conveyance drive motor 220. The cover member 260 has an extending part 260b that extends further to the front side of the apparatus than the end part 250b on the front side of the apparatus of the displacement sensor 250. A plurality of heat exhaust holes 262 for exhausting the heat in the cover member 260 to the outside are formed in the extending portion 260b.

[Function example of resist unit 200B]
FIG. 8A and FIG. 8B are diagrams for explaining the function of the resist unit 200B. As shown in FIGS. 8A and 8B, when the image forming unit base 300 is pulled out of the apparatus main body 102 by the user when the developing device 4 is replaced or maintained, the developing device 4 is moved. Since the toner replenishing port 310 is exposed, a part of the toner may fall on the upper surface of the cover member 260 in some cases. In the resist unit 200B of the present embodiment, the heat exhaust hole 262 of the cover member 260 is formed on the extended portion 260b provided on the front side of the apparatus and at a position different from the dropping position of the toner supply port 310. Therefore, the falling toner can be prevented from entering the cover member 260.

  As described above, according to the second embodiment, since the heat exhaust hole 262 is formed in the extending portion 260a of the cover member 260, the heat in the cover member 260 is released from the heat exhaust hole 262 to the outside. Therefore, it is possible to prevent the temperature increase of the deviation sensor 250 in the cover member 260. Further, since the deviation sensor 250 is disposed at a position away from a motor such as the registration roller conveyance drive motor 220, it is possible to effectively prevent the temperature deviation of the deviation sensor 250 due to exhaust heat of the motor. . Accordingly, it is possible to prevent the detection accuracy of the deviation sensor 250 from being lowered or the durability from being lowered.

  Further, according to the second embodiment, since the extended portion 260a is provided on the upper surface portion of the cover member 260 different from the drop position of the toner replenishing port 310 to form the heat exhaust hole 262, the image forming unit base 300 is provided. Even if the toner drops from the toner supply port 310 when the toner is pulled out, the toner can be prevented from entering the cover member 260. Thereby, the fall of the detection accuracy of the deviation sensor 250, etc. can be prevented.

<Third Embodiment>
In the third embodiment, a shutter mechanism 270 that opens and closes the heat exhaust hole 262 is added to the configuration of the resist unit 200A described in the first embodiment. Since the other configurations and operations of the image forming apparatus 100 are the same as those in the first embodiment, common constituent elements are denoted by the same reference numerals, and detailed description thereof is omitted.

[Configuration example of resist unit 200C]
FIG. 9 shows an example of the configuration of a resist unit 200C according to the third embodiment. In FIG. 9, the heat exhaust hole 262 formed in the cover member 260 is illustrated as a single hole for convenience, but actually, it can be configured by a plurality of holes as illustrated in FIG. 2 and the like. .

  As shown in FIG. 9, the registration unit 200 </ b> C opens and closes the heat exhaust hole 262 formed in the cover member 260 in addition to the above-described registration roller pair 210, the offset sensor 250, the registration roller conveyance drive motor 220, and the like. The shutter mechanism 270 is provided. The shutter mechanism 270 includes a shutter member 272, a shutter mounting member 274, a rotation shaft 276, a fixing member 278, a rotation member 280, and an urging member 282.

  The shutter member 272 includes a flat plate-like main body 272a and a plurality of openings 272b formed in the main body 272a. The lengths of the main body 272a in the paper transport direction D1 and the main scanning direction D2 are selected to be large enough to cover the entire area of the cover member 260 in which the plurality of heat exhaust holes 262a are formed. The plurality of openings 272b are holes that penetrate the main body 272a in the thickness direction, and are formed at positions (same positions) corresponding to the positions at which the plurality of heat exhaust holes 262 described above are formed.

  The shutter mounting member 274 is a member having an L-shaped side surface. One end portion of the shutter member 272 is attached to the vertical portion, and the horizontal portion of the shutter mounting member 274 is attached to the lower portion of the rotating shaft 276. Yes. The shutter mounting member 274 is movable toward the front side of the apparatus and the back side of the apparatus in the main scanning direction D2 as the rotation shaft 276 rotates.

  The rotation shaft 276 is rotatably attached to a casing constituting the apparatus main body 102 via a fixing member 278. The rotating member 280 is a flat plate-like member, one end of which is attached to the rotating shaft 276, and the other end is urged toward the front side of the apparatus by the urging member 282. The urging member 282 is made of, for example, a spring, and is disposed between the rotating member 280 and the apparatus main body 102.

[Operation example of shutter mechanism 270]
10A and 10B show an example of the operation of the shutter mechanism 270. FIG. As shown in FIG. 10A, in a state where the image forming unit base 300 is loaded in the apparatus main body 102, the image forming unit base 300 presses the rotating member 280 toward the back side of the apparatus, so that the biasing member 282 is It is in a compressed state. In this case, since the position of the opening 272b formed in the shutter member 272 and the position of the heat exhaust hole 262 of the cover member 260 overlap, the heat exhaust hole 262 of the cover member 260 is opened.

  On the other hand, as shown in FIG. 10B, when the image forming unit base 300 is pulled out from the apparatus main body 102 due to replacement or maintenance of the developing device 4, the image forming unit base 300 is moved in the main scanning direction D2. Accordingly, the image forming unit base 300 and the rotating member 280 are separated from each other, so that the rotating member 280 is tilted toward the apparatus front side by the urging force of the urging member 282. Accordingly, the rotation shaft 276 rotates and the shutter mounting member 274 horizontally moves to the back side of the apparatus, so that the shutter member 272 attached to the shutter mounting member 274 also horizontally moves to the back side of the apparatus. As a result, the opening 272b of the shutter member 272 moves to a position where it does not overlap the exhaust heat hole 262 of the cover member 260, so that the exhaust heat hole 262 is closed.

  As described above, according to the third embodiment, the heat exhaust hole 262 can be closed by the shutter member 272 even when the image forming unit mount 300 is pulled out from the apparatus main body 102. Even when 262 is formed below the toner supply port 310, it is possible to reliably prevent the toner from entering the cover member 260. Thereby, the contamination of the deviation sensor 250 can be prevented, and the detection accuracy of the deviation sensor 250 can be prevented from being lowered.

<Fourth embodiment>
The fourth embodiment is different from the first embodiment in that the heat exhaust hole 262 is opened and closed by a shutter mechanism 370 according to the job state. Since the other configurations and operations of the image forming apparatus 100 are the same as those in the first embodiment, common constituent elements are denoted by the same reference numerals, and detailed description thereof is omitted.

[Configuration example of resist unit 200D]
FIG. 11 shows an example of the configuration of a resist unit 200D according to the fourth embodiment. As shown in FIG. 11, the registration unit 200 </ b> D includes a control unit 50 and a shutter mechanism 370 in addition to the registration roller pair 210, the offset sensor 250, the cover member 260, and the registration roller conveyance drive motor 220.

  The control unit 50 is an arithmetic processing unit that controls the entire apparatus, and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and the like. The CPU of the control unit 50 controls each unit of the image forming apparatus 100 by executing software (program) read from the ROM, and executes image forming processing including misalignment correction of the paper P. The control unit 50 is connected to a deviation sensor 250, a registration roller conveyance drive motor 220, and a shutter mechanism 370.

  The shutter mechanism 370 includes a shutter member 372 and a shutter member drive motor 376. The shutter member 372 is a member made of a metal material having a flat plate shape, and is disposed so as to overlap below the cover member 260. The shutter member 372 has a plurality of openings 374 at positions corresponding to the heat exhaust holes 262 of the cover member 260. In FIG. 11, the heat exhaust hole 262 and the opening 374 are illustrated as a single hole for convenience, but may actually be configured with a plurality of holes as illustrated in FIG. 2 and the like.

  The shutter member drive motor 376 is composed of, for example, a stepping motor or the like, and is connected to the shutter member 372 via a gear or the like. The shutter member drive motor 376 is driven based on the drive signal supplied from the control unit 50 to move the shutter member 372 along the main scanning direction D2. The shutter member drive motor 376 adjusts the position of the shutter member 372 according to, for example, the job execution status.

[Operation Example of Image Forming Apparatus 100]
FIG. 12 is a flowchart illustrating an example of the operation of the image forming apparatus 100 during the image forming process according to the fourth embodiment. The CPU 52 of the control unit 50 implements the processing shown in the flowchart of FIG. 12 by executing the program read from the ROM 54.

  As shown in FIG. 12, in step S100, the control unit 50 determines whether it is time to start a job. The job start timing can be determined based on, for example, whether a job is transmitted from a computer or the like connected via a network. If the control unit 50 determines that it is not time to start the job, it waits until the job is transmitted. On the other hand, if the control unit 50 determines that it is time to start the job, the process proceeds to step S110.

  In step S110, when it is time to start the job, the control unit 50 drives the shutter member drive motor 376 to place the shutter member 372 at a position where the opening 374 of the shutter member 372 and the heat exhaust hole 262 of the cover member 260 overlap. To move the exhaust heat hole 262 to an open state. When step S110 ends, the process proceeds to step S120.

  In step S120, the control unit 50 starts printing. Specifically, charging, exposure, development processing, and the like are performed based on image data included in the job, and a predetermined image is transferred to the paper P sent out from the paper supply unit 20. If execution of the process of step S120 is started, it will progress to step S130.

  In step S130, the control unit 50 determines whether the job is completed or a jam is detected. If the control unit 50 determines that the job has not ended or that a jam has not been detected, the control unit 50 continues to execute the job. On the other hand, when the control unit 50 determines that the job is completed or a jam is detected, the process proceeds to step S140.

  In step S140, when the job is completed or a jam is detected, the control unit 50 drives the shutter member driving motor 376 so that the opening 374 of the shutter member 372 and the exhaust heat hole 262 of the cover member 260 do not overlap. By moving the shutter member 372 to the position, the exhaust heat hole 262 is closed. When step S140 ends, the process proceeds to step S150.

  In step S150, the control unit 50 stands by with the heat exhaust hole 262 opened until a new job is started or another jam is detected. In this example, such processing is repeatedly executed.

  As described above, according to the fourth embodiment, even when the toner spills onto the cover member 260 from the toner supply port 310 when the image forming unit base 300 is pulled out, the heat release hole is discharged by the shutter member 272. Since 262 can be closed, toner can be prevented from entering the cover member 260. As a result, it is possible to prevent the toner from adhering to the deviation sensor 250 from being contaminated, and to prevent the detection accuracy of the deviation sensor 250 from being lowered.

  Further, according to the fourth embodiment, when the job is finished, the heat exhaust hole 262 is closed, so that dust such as toner enters the cover member 260 after the job is finished and the displacement sensor 250 can be prevented from being soiled. In this case, since the driving of the registration roller transport driving motor 220 is stopped with the end of the job, the temperature in the deviation sensor 250 does not increase.

  Further, when the image forming unit mount 300 is loaded and a job is executed, the heat exhaust hole 262 is opened by the shutter member 272, so that the heat in the cover member 260 can be released from the heat exhaust hole 262 to the outside. Thereby, the temperature rise of the deviation sensor 250 in the cover member 260 can be prevented, and the detection accuracy of the deviation sensor 250 can be prevented from being lowered or the durability can be prevented from being lowered.

  Note that the present technology should not be construed as being limited to the embodiments of the technology described above. Embodiments of this technology disclose the present technology in the form of exemplifications, and include those in which those skilled in the art add changes to the embodiments without departing from the gist of the present technology.

  For example, in the above-described embodiment, the example in which the toner replenishing port 310 is disposed on the back side of the apparatus has been described. However, the present invention is not limited to this, and the toner replenishing port 310 is disposed on the front side of the apparatus. You can also. In this case, the positions of the offset sensor 250, the extended portion 260a of the cover member 260, and the exhaust heat holes 262 described in the first to fourth embodiments are configured to be reversed.

  In the above-described embodiment, the bending correction of the paper P is performed by the registration roller pair 210. However, the present invention is not limited to this. For example, the registration roller pair 210 is used as a transport roller pair, and a known side guide plate and shutter member are provided upstream of the transport roller pair in the paper transport direction D1, and the bending of the paper P is corrected by these means. You may make it do.

  Further, the image forming apparatus 100 shown in FIG. 1 forms a color image, but the present invention is not limited to an image forming apparatus that forms a color image, but can be applied to an image forming apparatus that forms a monochrome image. it can.

50 Control unit 100 Image forming apparatus 200A, 200B, 200C, 200D Registration unit 210 Registration roller pair (roller pair)
220 Registration roller transport drive motor (motor)
250 Offset sensor 250a, 250b End portion 260 Cover member 260a, 260b Extension portion 262 Heat exhaust hole 270 Shutter mechanism 272 Shutter member 274 Shutter mounting member 274
276 Rotating shaft 278 Fixed member 280 Rotating member 282 Biasing member 300 Image forming unit mount 370 Shutter mechanism 372 Shutter member 376 Shutter member drive motor (motor)
D1 paper transport direction, sub-scanning direction (first direction)
D2 main scanning direction (second direction)
P paper

Claims (9)

A pair of rollers for correcting the deviation of the paper by moving the paper in a second direction orthogonal to the first direction of the paper conveyance direction;
A deviation sensor provided on the downstream side of the roller pair in the first direction and detecting deviation of the paper;
A cover member that covers the offset sensor,
The image forming apparatus, wherein the cover member has a hole for discharging heat inside the cover member at a position different from a position where the displacement sensor is arranged. The displacement sensor has a longitudinal direction extending in the second direction,
The cover member has an extending portion extending in a second direction from an end portion on one side of the offset sensor,
The image forming apparatus according to claim 1, wherein the hole is provided in the extending portion of the cover member. A unit that is provided above the offset sensor and has a developing device that can be inserted into and removed from the apparatus main body in the second direction;
A motor for driving the roller pair,
The image forming apparatus according to claim 2, wherein the motor is provided at an end portion of the roller pair on a drawer side of the unit. The offset sensor is disposed on the motor side,
The image forming apparatus according to claim 3, wherein the extending portion of the cover member is provided at an end portion of the cover member opposite to the motor. The offset sensor is disposed on an end side of the roller pair on the side opposite to the motor,
The image forming apparatus according to claim 3, wherein the extending portion of the cover member is provided at an end of the cover member on the motor side. The image forming apparatus according to claim 5, further comprising a shutter mechanism for opening and closing the hole of the cover member. The control unit according to claim 6, further comprising: a control unit configured to control the operation of the shutter mechanism so that the hole of the cover member is opened before the job is started and the hole of the cover member is closed after the job is completed. Image forming apparatus. The shutter mechanism is
The unit operates in conjunction with an insertion / removal operation of the unit with respect to the apparatus main body, opens the hole of the cover member in a state where the unit is loaded in the apparatus main body, and the cover member in a state where the unit is pulled out from the apparatus main body. The image forming apparatus according to claim 6, wherein the hole is closed. The image forming apparatus according to any one of claims 1 to 8, wherein the roller pair is a registration roller that forms a loop on the paper and corrects the bending of the paper.

Images