JP2021165182A - Image forming device - Google Patents

Abstract

To provide an image forming device for detecting the position of a recording material on a transportation passage.SOLUTION: An image forming device forming images on a recording material is provided with: a loading section for loading the recording material; a paper supply section for supplying the recording material from the loading section to a transportation passage; a sound generating section for generating sound at the timing when the record material reaches a predetermined position on the transportation passage and/or the timing when the record material leaves the predetermined position; a sound detection section for detecting the sound generated by the sound generating section; and a control section for controlling transportation of the recording material based on the result of detection with the sound detection section.SELECTED DRAWING: Figure 6

Description

The present invention relates to an image forming apparatus such as a copying machine or a printer.

Conventionally, in an image forming apparatus, sheet transfer control is performed by detecting the timing at which a sheet reaches the optical sensor using an optical sensor such as a photointerruptor. Patent Document 1 discloses an image forming system that identifies an abnormal portion by detecting a sound generated during an image forming operation by the image forming apparatus. Further, Patent Document 2 discloses a control method for detecting the type of sheet by detecting the sheet rubbing noise during transportation.

Japanese Unexamined Patent Publication No. 7-302019 Japanese Unexamined Patent Publication No. 2003-212386

In the conventional technique, the transfer control of the sheet (recording material) is performed by using an optical sensor such as a photointerruptor during the image forming operation. When the photo interrupter is arranged in the image forming apparatus and the sheet transfer timing is detected, the cost of the photo interrupter is incurred, and the wiring for supplying power to the photo interrupter and the detection signal of the photo interrupter are received. Wiring needs to be laid. However, when laying the wiring, in addition to the cost of the wiring itself, a wiring cover for hiding the wiring, a relay board for relaying the wiring, and the like are required, and the cost for laying the wiring is high. In particular, when the wiring is arranged in a movable part such as a door, it is necessary to take measures for passing the wiring between the main body and the door, which hinders the miniaturization of the image forming apparatus itself. Further, if the photo interrupter is arranged in a place where the ambient temperature is high, such as in the vicinity of the fuser, there is a problem that the reliability and durability of the photo interrupter are impaired.

In view of the above problems, the present invention provides an image forming apparatus capable of detecting the position of a recording material in a transport path without using an optical sensor such as a photointerruptor that detects the transport timing of the recording material. The purpose.

In order to achieve the above object, the image forming apparatus according to the present invention is
An image forming apparatus that forms an image on a recording material.
A loading unit for loading the recording material and
A paper feeding unit that feeds the recording material from the loading unit to the transport path, and a paper feeding unit.
A sound generating unit that generates sound at at least one timing when the recording material reaches a predetermined position on the transport path and when the recording material is separated from the predetermined position.
A sound detection unit that detects the sound generated by the sound generation unit, and
A control unit that controls the transport of the recording material based on the detection result of the sound detection unit, and
It is characterized by having.

According to the present invention, it is possible to provide an image forming apparatus capable of detecting the position of a recording material in a transport path without using an optical sensor such as a photointerruptor that detects the transport timing of the recording material.

Overall configuration diagram of the image forming apparatus according to the first embodiment Explanatory drawing of sound generation mechanism which concerns on Example 1. Hardware configuration diagram according to the first embodiment A control block diagram showing a system configuration of the image forming apparatus according to the first embodiment. Explanatory drawing of volume waveform according to Example 1. Flowchart at the time of printing according to the first embodiment Explanatory drawing of volume waveform according to Example 1. Flow chart for determining the sheet arrival timing according to the first embodiment Explanatory drawing of sound generation mechanism which concerns on Example 2 Explanatory drawing of volume waveform according to Example 2. Explanatory drawing of volume waveform according to Example 2. Flow chart for determining the sheet arrival timing according to the second embodiment

Hereinafter, embodiments for carrying out the present invention will be described in detail exemplarily based on examples with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments. Further, in each of the following figures, components that are not necessary for the description of the embodiment will be omitted from the drawings.

(Example 1)
The first embodiment to which the present invention can be applied will be described below.
<Structure of image forming apparatus>
The overall configuration of the image forming apparatus 100 according to this embodiment will be outlined with reference to FIG. The image forming apparatus 100 forms an electrostatic latent image by image light formed based on a pixel signal transmitted from a video controller (not shown), develops the electrostatic latent image, and produces a visible image (toner image). A color visible image is formed by superimposition transfer. The image forming apparatus 100 transfers this color visible image to a sheet 2 as a recording material (recording medium), and fixes the color visible image on the sheet 2. The image forming units SY, SM, SC, and SY are photosensitive drums 5Y, 5M, 5C, 5K for each station in which the developed colors are juxtaposed, charging means 7Y, 7M, 7C, 7K as primary charging means, and developing means 8Y, 8M. , 8C, 8K, primary transfer rollers 4Y, 4M, 4C, 4K.

The photosensitive drums 5Y, 5M, 5C, 5K, charging means 7Y, 7M, 7C, 7K, and developing means 8Y, 8M, 8C, 8K as image carriers are cartridges 22Y, 22M, 22C that can be attached to and detached from the image forming apparatus 100. , 22K respectively. The photosensitive drum 5 (5Y, 5M, 5C, 5K) is configured by applying an organic optical transmission layer to the outer periphery of an aluminum cylinder. The image forming portions SY, SM, SC, and SY charge the photosensitive drums 5 (5Y, 5M, 5C, 5K) of each color of yellow (Y), magenta (M), cyan (C), and black (K). The four charging means 7 (7Y, 7M, 7C, 7K) are provided. The charging means 7Y, 7M, 7C, 7K have primary charging rollers 7YR, 7MR, 7CR, 7KR.

The photosensitive drums 5Y, 5M, 5C, and 5K rotate by transmitting the driving force of a drive motor (not shown), and rotate clockwise according to the image forming operation. Since the photosensitive drums 5Y, 5M, 5C, and 5K have the same configuration, the photosensitive drums 5Y, 5M, 5C, and 5K are collectively referred to as the photosensitive drum 5 below. The exposure light to the photosensitive drum 5 is sent from the optical unit 10, and the surface of the photosensitive drum 5 is selectively exposed to form an electrostatic latent image on the surface of the photosensitive drum 5. The image forming units SY, SM, SC, and SY develop yellow (Y), magenta (M), cyan (C), and black (K) colors in order to visualize the electrostatic latent image. A number of developing means 8 (8Y, 8M, 8C, 8K) are provided. The developing means 8Y, 8M, 8C, 8K have developing rollers 8YR, 8MR, 8CR, 8KR as a developing agent carrier.

At the time of image formation, the intermediate transfer belt 12 rotates counterclockwise in contact with the photosensitive drum 5. The visible images of each color are superimposed and transferred to the intermediate transfer belt 12 by the primary transfer bias applied to the primary transfer rollers 4Y, 4M, 4C, and 4K, so that the color visible images are transferred to the intermediate transfer belt 12. By applying a secondary transfer bias to the secondary transfer roller 9 and narrowly transporting the sheet 2 at the position of the secondary transfer roller 9, the color visible image on the intermediate transfer belt 12 is simultaneously superimposed and transferred to the sheet 2. The primary transfer roller 4Y, 4M, 4C, 4K and the secondary transfer roller 9 rotate with the rotation of the intermediate transfer belt 12.

The image forming apparatus 100 has a cassette paper feed tray 101 as a loading unit for loading the sheet 2 and a paper feed unit for feeding the sheet 2 from the cassette paper feed tray 101 into the transport path (sheet transport path) of the sheet 2. A paper feed roller 102 is provided. In the cassette paper feed tray 101, a paper feed motor (not shown) is driven to turn on a paper feed solenoid (not shown), so that the paper feed roller 102 rotates and the sheet 2 is fed to the paper feed transfer roller 40. NS. The paper feed transfer roller 40 rotates and conveys the sheet 2 to the resist roller 3 along the transfer passage 25, and the sheet 2 is conveyed to the secondary transfer roller 9 by the resist roller 3.

Further, the image forming apparatus 100 includes a microphone 70 as a sound detecting unit for detecting the sound information in the image forming apparatus 100. The microphone 70 is used for transport control of the image forming apparatus 100. In this embodiment, the microphone 70 will be used as the signal input means of the conversion unit 206, but if the sound information in the image forming apparatus 100 can be detected, the signal input means of the conversion unit 206 may be an ultrasonic receiver or the like. You may use the device of.

The image forming apparatus 100 detects the front end and the rear end of the sheet 2 being conveyed by detecting the sound generation of the resist section sound generation mechanism 71 with the microphone 70, and the sheet 2 is normally transferred from the cassette paper feed tray 101. Determine that it is being transported. The sound generation by the resist section sound generation mechanism 71 and the sound detection by the microphone 70 will be described later.

The fixing device 13 fixes the color visible image transferred to the sheet 2 while transporting the sheet 2. The fixing device 13 includes a fixing roller 14 for heating the sheet 2 and a pressure roller 15 for pressing the sheet 2 against the fixing roller 14. The fixing roller 14 and the pressure roller 15 are formed in a hollow shape, and a heater is built in the fixing roller 14. That is, the sheet 2 holding the color visible image is conveyed by the fixing roller 14 and the pressure roller 15, and the toner (developer) is fixed to the surface of the sheet 2 by applying heat and pressure to the sheet 2.

Further, the image forming apparatus 100 reversely conveys the sheet 2 in order to form an image on the second surface (for example, the back surface) of the sheet 2 after the image formation of the first surface (for example, the front surface) of the sheet 2 is completed. It has a mechanism for. In this embodiment, the image forming apparatus 100 includes a reversing roller 62 that reverses forward and reversely by receiving a driving force of a reversing motor (not shown). The reversing roller 62 can reverse the sheet 2 sent from the double-sided aisle 60 by the reverse rotation of the reversing motor and convey it to the double-sided aisle 56. Further, the image forming apparatus 100 includes a double-sided transfer roller 55 and a double-sided refeed roller 57 that rotate by receiving a driving force from a double-sided transfer motor (not shown). The double-sided transfer roller 55 and the double-sided re-feeding roller 57 convey the sheet 2 inverted and conveyed from the reversing roller 62 along the double-sided aisle 56, and the sheet 2 is brought together so that the sheet 2 joins in the middle of the aisle 25. Can be transported.

Further, the image forming apparatus 100 has a double-sided flapper 51 as a guiding means. The double-sided flapper 51 selectively guides the sheet 2 that has been guided by the transport passage 25 and exits the fuser 13 to either the paper ejection roller 52 or the reversing roller 62. The position of the double-sided flapper 51 is switched by operating the plunger-type double-sided flapper solenoid 223 by the drive unit 207 shown in FIG. 4, and guides the sheet 2 to either the paper ejection roller 52 or the reversing roller 62. In this embodiment, the double-sided flapper 51 is configured to guide the sheet 2 that has passed through the fuser 13 to the reversing roller 62 when the double-sided flapper solenoid 223 is pulled (ON). Further, in the present embodiment, the double-sided flapper 51 is configured to guide the sheet 2 that has passed through the fuser 13 to the paper ejection roller 52 in a state where the double-sided flapper solenoid 223 is not pulled (OFF).

The image forming apparatus 100 detects the front end and the rear end of the sheet 2 being conveyed by detecting the sound generation of the paper ejection section sound generation mechanism 72 by the microphone 70, and the sheet 2 is transferred to the paper ejection roller 52 or the reversing roller 62. Is determined to be transported normally. Further, the sheet 2 guided to the double-sided transfer passage 60 is conveyed by the rotating fixing roller 14 and the pressure roller 15 and reaches the switching member 61 at the first position (the position shown by the solid line in FIG. 1). The switching member 61 is located at the first position (the position shown by the solid line in FIG. 1) due to its own weight.

Then, when the sheet 2 is further conveyed, the sheet 2 reaches the reversing roller 62 while pushing up the switching member 61, and the tip of the sheet 2 protrudes from the frame of the image forming apparatus 100. In the state where the sheet 2 pushes up the switching member 61, the switching member 61 has moved to the second position (the position indicated by the dotted line). Here, by the time the rear end of the sheet 2 passes through the switching member 61 and the rear end of the sheet 2 reaches the double-sided reversing position in front of the reversing roller 62 by a predetermined distance, the switching member 61 is due to its own weight. It has returned to the first position (the position shown by the solid line in FIG. 1). As a result, when the reversing roller 62 rotates in the reverse direction, the sheet 2 is conveyed to the double-sided transfer passage 56 along the upper surface of the switching member 61.

Next, the paper ejection section sound generation mechanism 72 of this embodiment will be described with reference to FIG. 2 (a) to 2 (f) are explanatory views of the paper ejection section sound generating mechanism 72, and show the positional relationship between the sheet 2 and the paper ejection section sound generating mechanism 72. FIG. 2A is a side view (horizontal direction) of a state before the sheet 2 reaches the mechanical flag 73 of the paper ejection unit sound generation mechanism 72. FIG. 2B is a perspective view of a state before the seat 2 reaches the mechanical flag 73. FIG. 2C is a view of the state when the tip of the seat 2 reaches the mechanical flag 73 as viewed from the horizontal direction (horizontal direction). FIG. 2D is a perspective view of a state when the tip of the seat 2 reaches the mechanical flag 73. FIG. 2E is a view of a state when the sheet 2 is further conveyed after the tip of the sheet 2 reaches the mechanical flag 73, as viewed from the lateral direction (horizontal direction). FIG. 2F is a perspective view of a state in which the seat 2 is further conveyed after the tip of the seat 2 reaches the mechanical flag 73.

The paper ejection section sound generating mechanism 72 has a mechanical flag 73 and a sound generating member 74, and is arranged on the sheet transport path in the vicinity of the fuser 13. When the sheet 2 is conveyed and reaches the mechanical flag 73, the mechanical flag 73 comes into contact with the tip of the sheet 2 and rotates around the rotation axis of the mechanical flag 73 in the direction of the arrow in FIG. 2C. The rotation axis of the mechanical flag 73 is arranged on a bearing (not shown) of the main body of the image forming apparatus 100. The mechanical flag 73 comes into contact with the sound generating member 74 when rotating in the direction of the arrow in FIG. 2C. The sound generating member 74 is a member configured to generate a sound when it comes into contact with the mechanical flag 73. A part of the sound generating member 74 is composed of a leaf spring-shaped member, and when the mechanical flag 73 and the leaf spring-shaped member of the sound generating member 74 come into contact with each other, the sound generating member 74 is configured to generate a sound. ..

When the transfer of the sheet 2 is completed, the mechanical flag 73 is rotationally moved around the rotation axis of the mechanical flag 73 by a spring (not shown) in the direction opposite to the arrow direction in FIG. 2 (e), and the sheet transfer path (seat 2). It returns to the original position (the position before the transfer of the sheet 2) on the transport path). The mechanical flag 73 comes into contact with the sound generating member 74 when rotating in the direction opposite to the arrow direction in FIG. 2 (e). Therefore, when the rear end of the sheet 2 passes through the position of the paper ejection section sound generating mechanism 72 and the rear end of the sheet 2 no longer contacts the mechanical flag 73, the mechanical flag 73 comes into contact with the sound generating member 74. Therefore, the sound generating member 74 generates sound at the timing when the front end of the seat 2 reaches the mechanical flag 73 on the seat transport path and at the timing when the rear end of the seat 2 passes through the mechanical flag 73. In this way, the paper ejection section sound generation mechanism 72 generates a sound at the arrival timing of the front end of the sheet 2 and the arrival timing of the rear end of the sheet 2. Further, the resist section sound generation mechanism 71 also has the same configuration as the paper ejection section sound generation mechanism 72, and the resist section sound generation mechanism 71 has a configuration at the arrival timing of the front end of the sheet 2 and the arrival timing of the rear end of the sheet 2. It is configured to generate sound. Therefore, the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 are examples of the sound generating section. The resist section sound generating mechanism 71 is arranged on the sheet transport path between the resist roller 3 and the fixing device 13.

The resist section sound generation mechanism 71 and the paper ejection section sound generation mechanism 72 generate sound at the arrival timing of the front end of the sheet 2 and the arrival timing of the rear end of the sheet 2. By changing the configurations of the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72, the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 can be moved to the arrival timing of the tip of the sheet 2 or after the sheet 2. Sound may be generated at the timing of reaching the end. By changing the configuration of the leaf spring-like member of the sound generating member 74, the paper ejection section sound generating mechanism 72 generates a sound at the arrival timing of the front end of the sheet 2, and the sound is generated at the arrival timing of the rear end of the sheet 2. May not occur.

For example, when the mechanical flag 73 comes into contact with the upper surface of the leaf spring-shaped member of the sound generating member 74, the sound generating member 74 generates a sound, and the mechanical flag 73 comes into contact with the lower surface of the leaf spring-shaped member of the sound generating member 74. At that time, the sound generating member 74 may not generate a sound. The upper surface of the leaf spring-shaped member of the sound generating member 74 is an upward surface in the vertical direction, and the lower surface of the leaf spring-shaped member of the sound generating member 74 is a downward surface in the vertical direction. When the mechanical flag 73 comes into contact with the tip of the sheet 2 and rotates in the direction of the arrow in FIG. 2C, the mechanical flag 73 comes into contact with the upper surface of the leaf spring-shaped member of the sound generating member 74. When the rear end of the seat 2 does not come into contact with the mechanical flag 73 and the mechanical flag 73 is rotated in the direction opposite to the arrow direction in FIG. 2 (e) by a spring (not shown), the mechanical flag 73 has a leaf spring shape of the sound generating member 74. Contact the lower surface of the member. Therefore, the paper ejection section sound generation mechanism 72 generates a sound at the arrival timing of the front end of the sheet 2, and does not generate a sound at the arrival timing of the rear end of the sheet 2. By making the resist section sound generation mechanism 71 the same as the configuration of the paper ejection section sound generation mechanism 72, the resist section sound generation mechanism 71 generates sound at the arrival timing of the tip of the sheet 2, and the rear end of the sheet 2 No sound is generated at the arrival timing.

For example, when the mechanical flag 73 comes into contact with the lower surface of the leaf spring-shaped member of the sound generating member 74, the sound generating member 74 generates a sound, and the mechanical flag 73 comes into contact with the upper surface of the leaf spring-shaped member of the sound generating member 74. At that time, the sound generating member 74 may not generate a sound. When the mechanical flag 73 comes into contact with the tip of the sheet 2 and rotates in the direction of the arrow in FIG. 2C, the mechanical flag 73 comes into contact with the upper surface of the leaf spring-shaped member of the sound generating member 74. When the rear end of the seat 2 does not come into contact with the mechanical flag 73 and the mechanical flag 73 is rotated in the direction opposite to the arrow direction in FIG. 2 (e) by a spring (not shown), the mechanical flag 73 has a leaf spring shape of the sound generating member 74. Contact the lower surface of the member. Therefore, the paper ejection section sound generation mechanism 72 generates a sound at the arrival timing of the rear end of the sheet 2, and does not generate a sound at the arrival timing of the front end of the sheet 2. By making the resist section sound generation mechanism 71 the same as the configuration of the paper ejection section sound generation mechanism 72, the resist section sound generation mechanism 71 generates sound at the arrival timing of the rear end of the sheet 2, and the tip of the sheet 2 No sound is generated at the arrival timing.

As described with reference to FIG. 2, the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 utilize (use) the conveying force of the sheet 2 to generate sound. The resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 make a sound at at least one timing when the sheet 2 reaches a predetermined position on the sheet transport path and when the sheet 2 separates from the predetermined position on the sheet transport path. Occurs. As a result, the image forming apparatus 100 detects at least one of the front end and the rear end of the sheet 2 being conveyed by detecting the generated sound of the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 by the microphone 70. can do.

Next, the hardware configuration of this embodiment will be described with reference to FIG. FIG. 3 is a diagram showing the configuration of the device mainly related to the control of the present embodiment with respect to the hardware configuration of the image forming apparatus 100 shown in FIGS. 1 and 2. The video controller 202 transmits a command from the host computer 201 to the engine control unit 203. The engine control unit 203 controls the image forming apparatus 100. The host computer 201 and the video controller 202 are connected by a communication line 504, and the video controller 202 and the engine control unit 203 are connected by a communication line 505. When performing the image forming operation, the video controller 202 controls the engine control unit 203 by transmitting a command and receiving status data from the engine control unit 203 in accordance with a command from the host computer 201. ..

The engine control unit 203 is, for example, a control IC. The engine control unit 203 includes a CPU 508, a RAM 509, a ROM 510, a communication unit 511, a system timer 512, an I / O port 513, and the like, which are connected to each other via a bus 514. The CPU 508 controls various operations of the image forming apparatus 100. The RAM 509 temporarily stores control data necessary for the operation of the image forming apparatus 100. The ROM 510 non-volatilely stores the control table necessary for the operation of the program and the image forming apparatus 100. The communication unit 511 performs communication processing with the video controller 202. The system timer 512 generates timings required for various controls. The I / O port 513 inputs / outputs control signals to various units in the image forming apparatus 100. The microphone input circuit 515 inputs a signal from the microphone 70 and transmits the signal to the engine control unit 203. The double-sided flapper solenoid drive circuit 518, the paper feed motor drive circuit 519, and the fixing motor drive circuit 520 receive control signals from the engine control unit 203, and drive the double-sided flapper solenoid 223, the paper feed motor 209, and the fixing motor 211, respectively. Further, the resist unit sound generation mechanism 71 and the paper discharge unit sound generation mechanism 72 are not electrically connected to the engine control unit 203.

<Control unit configuration of image forming device>
Next, the system configuration of the entire control unit of the image forming apparatus 100 will be described with reference to the block diagram of FIG. As shown in FIG. 4, the engine control unit 203 includes a conversion unit 206, a drive unit 207, a seat transfer unit 205, and a seat transfer control unit 204. The conversion unit 206 converts the information acquired from the microphone 70 into volume data in order to detect the sound information. That is, the conversion unit 206 converts the detection result of the microphone 70 into volume data. The sheet transport unit 205 drives the resist roller 3 and the fixing roller 14 to transport the sheet 2. The drive unit 207 switches the position of the double-sided flapper 51 by operating the double-sided flapper solenoid 223, and guides the sheet 2 to either the paper ejection roller 52 or the reversing roller 62. The sheet transfer control unit 204 drives the resist roller 3 and the fixing roller 14 by controlling the sheet transfer unit 205. Further, the sheet transfer control unit 204 determines the transfer timing of the sheet 2 by detecting the sound generated from the resist unit sound generation mechanism 71 and the paper discharge unit sound generation mechanism 72 by the microphone 70 during the transfer of the sheet 2. Judgment is made, and the transfer control of the sheet 2 is performed.

<Sound detection and sheet transfer control>
Next, the sheet transfer control performed by the sheet transfer control unit 204, which is a feature of this embodiment, will be described with reference to FIGS. 5 and 6. FIG. 5 is a diagram showing the volume level of the sound detected by the microphone 70 from the start of image formation to the end of image formation when forming an image of one sheet 2. The horizontal axis of FIG. 5 indicates time, and the vertical axis of FIG. 5 indicates the volume level.

Here, the timing (a) in FIG. 5 is the start timing of driving the fixing motor 211 and the intermediate transfer belt 12. The timing (b) in FIG. 5 is the timing at which the drive of the paper feed motor 209 is started, that is, the timing at which the sheet 2 is started to be conveyed (paper feed start). The timing (c) in FIG. 5 is the timing at which the tip of the sheet 2 reaches the resist portion sound generation mechanism 71. The timing (d) in FIG. 5 is the timing at which the rear end of the sheet 2 reaches the resist portion sound generation mechanism 71. The timing (e) in FIG. 5 is the timing at which the tip of the sheet 2 reaches the paper ejection section sound generation mechanism 72. The timing (f) in FIG. 5 is the timing at which the rear end of the sheet 2 reaches the paper ejection section sound generation mechanism 72. The timing (g) in FIG. 5 is the timing at which the drive of the paper feed motor 209 is stopped, that is, the timing at which the paper feed at the sheet 2 is stopped. The timing (h) in FIG. 5 is the timing at which the operation of the intermediate transfer belt 12 and the fixing motor 211 is stopped after the seat 2 is ejected.

In addition, in order to make it easier to distinguish between the external sound, the driving sound inside the device, and the sheet transport sound, and the sound generated by the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72, a period during which sound is detected during printing. May be restricted. Here, the sheet transport control unit 204 may perform the sound detection determination process in the period (sound detection period) before and after each of the timings (c), (d), (e) and (f). The sheet transfer control unit 204 determines the start timing and end timing of each sound detection period from the immediately preceding operation timing.

For example, the start timing of the sound detection period A, which is the period before and after the timing (c), is the timing after the lapse of the first time from the timing (b) of the paper feed start of the sheet 2. Further, the end timing of the sound detection period A is the timing after the lapse of the second time, which is longer than the first time, from the timing (b) of the paper feed start of the sheet 2. The sheet transport control unit 204 sets the sound detection period A so that the sound detection starts after the lapse of the first time from the timing (b) and ends after the lapse of the second time from the timing (b). .. Therefore, the time obtained by subtracting the first time from the second time is the sound detection period A. The sheet transfer control unit 204 may set a first time and a second time longer than the first time based on the size of the sheet 2 (sheet size), the transfer speed of the sheet 2, and the like. Further, the sheet transport control unit 204 sets the first time and the second time for the timings (d), (e) and (f), respectively, and subtracts the first time from the second time to detect the sound. B, C and D may be set.

Further, the sheet transport control unit 204 compares the volume data of the conversion unit 206 with the reference level determined for each sound generation mechanism, and the front end of the sheet 2 or the rear end of the sheet 2 reaches each sound generation mechanism. Determine the timing. Then, the seat transfer control unit 204 performs transfer control (seat transfer control) of the sheet 2 with reference to these timings. In this way, the seat transfer control unit 204 controls the transfer of the sheet 2 based on the detection result of the microphone 70. The reference level and the details of the arrival determination process will be described later.

FIG. 6 is a flowchart of the sheet transport control unit 204 when printing is executed. Here, FIG. 6 shows a JAM determination operation performed during sheet transportation. The sheet transfer control unit 204 starts driving the fixing motor 211 and the intermediate transfer belt 12 at the timing (a) of FIG. 5 (S501). Next, the sheet transfer control unit 204 waits until the preparation for image formation such as the stable drive of the intermediate transfer belt 12 is completed (S502). When the preparation for image formation is completed, the sheet transfer control unit 204 starts driving the paper feed motor 209 at the timing (b) of FIG. 5 (S).
503), the transfer of the sheet 2 is started (S504).

When the transfer of the sheet 2 is started, the sheet transfer control unit 204 determines whether or not the tip of the sheet 2 has reached the position of the resist unit sound generating mechanism 71 on the sheet transfer path with reference to the start timing of the sheet transfer. .. The sheet transfer control unit 204 determines whether or not the tip of the sheet 2 has reached the position of the resist unit sound generation mechanism 71 (S505). If the microphone 70 does not detect sound within the first predetermined period, the sheet transport control unit 204 determines that the tip of the sheet 2 has not reached the position of the resist unit sound generation mechanism 71 (S505: No). , S507 is performed. The first predetermined period is a period from the timing of starting the transportation of the sheet 2 to the predetermined timing. Further, the first predetermined period may be the sound detection period A, which is a period before and after the timing (c) of FIG. On the other hand, when the microphone 70 detects a sound within the first predetermined period, the sheet transport control unit 204 determines that the tip of the sheet 2 has reached the position of the resist unit sound generation mechanism 71 (S505: Yes), and S506. Is processed. The details of the sound detection determination method will be described later.

Next, the sheet transfer control unit 204 determines whether or not the rear end of the sheet 2 has reached the position of the resist unit sound generation mechanism 71 (S506). If the microphone 70 does not detect sound within the second predetermined period, the sheet transport control unit 204 determines that the rear end of the sheet 2 has not reached the position of the resist unit sound generation mechanism 71 (S506: No). ), S507 is performed. The second predetermined period is a period from the timing when the tip of the sheet 2 reaches the position of the resist portion sound generation mechanism 71 to the predetermined timing according to the sheet size. The timing at which the tip of the sheet 2 reaches the position of the resist portion sound generation mechanism 71 is detected by the microphone 70. Further, the second predetermined period may be a sound detection period B which is a period before and after the timing (d) of FIG. On the other hand, when the microphone 70 detects a sound within the second predetermined period, the sheet transport control unit 204 determines that the rear end of the sheet 2 has reached the position of the resist unit sound generation mechanism 71 (S506: Yes). The process of S508 is performed.

Next, the sheet transfer control unit 204 detects the JAM of the sheet 2 at the position of the resist unit sound generation mechanism 71. The seat transfer control unit 204 determines that the sheet 2 jam has occurred, notifies the user of the sheet 2 jam (S507), and performs the process of S512. The jam of the sheet 2 is a defective transfer of the sheet 2 due to the sheet 2 not being conveyed normally. When the tip of the sheet 2 did not reach the position of the resist section sound generating mechanism 71, the sheet transport control section 204 jammed the sheet 2 before the sheet 2 reached the position of the resist section sound generating mechanism 71. Judge. When the rear end of the sheet 2 does not reach the position of the resist section sound generating mechanism 71, it is determined that the sheet 2 has jammed while the sheet 2 is passing through the position of the resist section sound generating mechanism 71.

Next, the sheet transport control unit 204 determines whether or not the tip of the sheet 2 has reached the position of the paper ejection unit sound generation mechanism 72 (S508). If the microphone 70 does not detect sound within the third predetermined period, the sheet transport control unit 204 determines that the tip of the sheet 2 has not reached the position of the paper ejection unit sound generation mechanism 72 (S508: No). ), S510 is performed. The third predetermined period is the distance between the position of the resist section sound generating mechanism 71 and the position of the paper ejection section sound generating mechanism 72 from the timing when the rear end of the sheet 2 reaches the position of the resist section sound generating mechanism 71. It is a period until a predetermined timing according to the situation. The timing at which the rear end of the sheet 2 reaches the position of the resist portion sound generation mechanism 71 is detected by the microphone 70. Further, the third predetermined period may be a sound detection period C which is a period before and after the timing (e) of FIG. On the other hand, when the microphone 70 detects a sound within the second predetermined period, the sheet transport control unit 204 determines that the tip of the sheet 2 has reached the position of the paper ejection unit sound generation mechanism 72 (S508: Yes). The process of S509 is performed.

Next, the sheet transport control unit 204 determines whether or not the rear end of the sheet 2 has reached the position of the paper ejection unit sound generation mechanism 72 (S509). If the microphone 70 does not detect sound within the fourth predetermined period, the sheet transport control unit 204 determines that the rear end of the sheet 2 has not reached the position of the paper ejection unit sound generation mechanism 72 (S509: No), the process of S510 is performed. The fourth predetermined period is a period from the timing when the tip of the sheet 2 reaches the position of the paper ejection unit sound generation mechanism 72 to the predetermined timing according to the sheet size. The timing at which the tip of the sheet 2 reaches the position of the paper ejection unit sound generation mechanism 72 is detected by the microphone 70. Further, the fourth predetermined period may be the sound detection period D, which is a period before and after the timing (f) of FIG. On the other hand, when the microphone 70 detects a sound within the fourth predetermined period, the sheet transport control unit 204 determines that the rear end of the sheet 2 has reached the position of the paper ejection unit sound generation mechanism 72 (S509: Yes). , S511 is performed.

Next, the sheet transfer control unit 204 detects the JAM of the sheet 2 at the position of the paper ejection unit sound generation mechanism 72. The seat transfer control unit 204 determines that the sheet 2 jam has occurred, notifies the user of the sheet 2 jam (S510), and performs the processing of S512. When the tip of the sheet 2 does not reach the position of the paper ejection unit sound generating mechanism 72, the sheet transport control unit 204 jams the sheet 2 before the sheet 2 reaches the position of the paper ejection unit sound generating mechanism 72. Judge that it has occurred. When the rear end of the sheet 2 does not reach the position of the paper ejection part sound generating mechanism 72, it is determined that the sheet 2 has jammed while the sheet 2 is passing through the position of the paper ejection part sound generating mechanism 72. do.

The sheet transfer control unit 204 waits until the paper ejection of the sheet 2 is completed (S511), and stops driving the paper feed motor 209 (S512). As a result, the paper feeding of the sheet 2 is stopped at the timing (g) of FIG. The sheet transfer control unit 204 stops driving the fixing motor 211 and the intermediate transfer belt 12 (S513) at the timing (h) of FIG. 5, and ends the printing operation.

Next, the sheet arrival detection method by the sound of the sheet transfer control unit 204 and the correction calculation method of the sheet arrival determination timing will be described with reference to FIGS. 7 and 8. FIG. 7 is an enlarged view of the volume waveform at the timing (c) of FIG. 5, and shows a method of detecting the sheet arrival timing. In FIG. 7, the rising timing of the volume waveform is defined as the timing (sheet arrival timing) T1 at which the tip of the sheet 2 reaches the position of the resist portion sound generation mechanism 71. The sheet transport control unit 204 determines the sheet arrival timing (sound detection timing) T1 immediately after detecting the volume peak (maximum value of the volume). Further, the seat transport control unit 204 calculates the actual seat arrival timing T by correcting the seat arrival timing T1 to avoid a delay in determining the position detection of the seat 2.

The actual calculation of the sheet arrival timing T1 is performed in the order of the following processes (1) to (3). In the following processes (1) to (3), the timing T1 at which the tip of the sheet 2 reaches the position of the resist portion sound generating mechanism 71 is described. The same applies to the timing at which the rear end of the sheet 2 reaches the position of the resist portion sound generating mechanism 71 and the timing at which the front end or the rear end of the sheet 2 reaches the position of the paper ejection portion sound generating mechanism 72.

(1) Detection of sound rise When the volume exceeds a predetermined first reference value (first reference threshold value), the sheet transport control unit 204 sets the absolute time T1 when the volume exceeds the first reference value. It is stored in a storage unit such as RAM 509 and ROM 510.

(2) Detection of volume peak (sound peak) After the volume exceeds a predetermined second reference value (second reference threshold) larger than the first reference value, the volume is smaller than the second reference value. When the value becomes equal to or less than the reference value (third reference threshold value), the sheet transport control unit 204 detects the volume peak and determines the absolute time T1 of the above process (1).

(3) Correction of sound wave arrival time The sheet transport control unit 204 subtracts the time T2 from the absolute time T1. The time T2 is the time until the sound wave is transmitted through the distance from the microphone 70 to the resist section sound generation mechanism 71. Assuming that the distance from the microphone 70 to the resist section sound generation mechanism 71 is L (mm) and the sound velocity is c (340000 (mm / s)), T2 = L / c (s). As a result, the timing T at which the tip of the sheet 2 actually reaches the resist portion sound generation mechanism 71 is represented by T = T1-T2.

FIG. 8 is a flowchart for determining the timing at which the tip of the sheet 2 reaches the position of the resist portion sound generation mechanism 71. First, the seat transfer control unit 204 determines whether the first time has elapsed from the start of transfer of the sheet 2 (S521). When the first time has elapsed from the start of transporting the sheet 2 (S521: Yes), the sheet transport control unit 204 starts sound detection (S522) and performs the process of S523. The sheet transfer control unit 204 determines whether the second time has elapsed from the start of transfer of the sheet 2 (S523). When the second time has elapsed from the start of the transfer of the sheet 2 (S523: Yes), the sheet transfer control unit 204 performs the process of S535.

When the second time has not passed from the start of the transfer of the sheet 2 (S523: No), the sheet transfer control unit 204 determines whether the volume has reached the first reference value or more (S524). When the volume is less than the first reference value (S524: No), the sheet transport control unit 204 repeats each process of S523 and S524 until the volume becomes equal to or higher than the first reference value. When the volume becomes equal to or higher than the first reference value (S524: Yes), the sheet transport control unit 204 stores the absolute time T1 when the volume exceeds the first reference value in the storage unit (S525).

Next, the sheet transport control unit 204 performs a process for detecting the volume peak in S526 and S527. The sheet transfer control unit 204 determines whether or not the second time has elapsed from the start of transfer of the sheet 2 (S526). When the second time has elapsed from the start of the transfer of the sheet 2 (S526: Yes), the sheet transfer control unit 204 performs the process of S535. When the second time has not passed from the start of the transfer of the sheet 2 (S526: No), the sheet transfer control unit 204 determines whether the volume has reached the second reference value or more (S527). When the volume is less than the second reference value (S527: No), the sheet transport control unit 204 repeats each process of S526 and S527 until the volume becomes equal to or higher than the second reference value.

When the volume becomes equal to or higher than the second reference value (S527: Yes), the sheet transport control unit 204 determines that the volume has entered the peak range, and performs the process of S528. In S528 and S529, the sheet transport control unit 204 performs a process of determining whether the volume is less than the third reference value in order to determine the peak of the volume. The sheet transfer control unit 204 determines whether the second time has elapsed from the start of transfer of the sheet 2 (S528). When the second time has elapsed from the start of the transfer of the sheet 2 (S528: Yes), the sheet transfer control unit 204 performs the process of S534.

When the second time has not passed from the start of the transfer of the sheet 2 (S528: No), the sheet transfer control unit 204 determines whether the volume has become less than the third reference value (S529). When the volume becomes less than the third reference value (S529: Yes), the sheet transport control unit 204 determines that the volume has passed the peak (that is, the volume has dropped from the peak) (S530). Next, the seat transfer control unit 204 determines the seat arrival timing T1 (S531) and performs a correction calculation (T = T1-T2) for the seat arrival timing T1 (S532). After that, the sheet transport control unit 204 ends the sound detection by the microphone 70 when the tip of the sheet 2 reaches the position of the resist unit sound generation mechanism 71 (S533).

When the volume exceeds the second reference value (S527: Yes), but the volume does not fall below the third reference value by the time the second time elapses from the start of transporting the sheet 2 (S528: Yes, S529: No). , The sheet transfer control unit 204 determines that the volume peak cannot be determined. In this case, although the transportation of the sheet 2 is delayed, the tip of the sheet 2 can be detected. Since the detection of the volume peak is within the permissible range, it is preferable to determine the sheet arrival timing T1. Therefore, the sheet transport control unit 204 determines that the volume peak has been detected (S534), and performs the process of S531.

If the volume does not exceed the first reference value (S523: Yes, S524: No) by the time the second time elapses from the start of transporting the sheet 2, the sheet transport control unit 204 determines that the volume cannot be detected. (S535). When the volume exceeds the first reference value (S524: Yes), but the volume does not exceed the second reference value by the time the second time elapses from the start of transporting the sheet 2 (S526: Yes, S527: No). , The sheet transport control unit 204 determines that the volume cannot be detected (S535). In these cases, since the tip of the seat 2 cannot be detected, the seat transport control unit 204 ends the sound detection without determining the seat arrival timing T1 (seat arrival timing T1 = 0 (error)) (S533). ).

The flowchart of FIG. 8 describes a case where the timing at which the tip of the sheet 2 reaches the position of the resist portion sound generating mechanism 71 is determined. Regarding the timing when the rear end of the sheet 2 reaches the position of the resist section sound generating mechanism 71 and the timing when the front end or the rear end of the sheet 2 reaches the position of the paper ejection section sound generating mechanism 72, each process of the flowchart of FIG. It can be determined by performing the same processing as in. In this case, the lengths of the first time and the second time in the flowchart of FIG. 8 are changed as appropriate. As described above, the seat transfer control unit 204 has at least one of the timing at which the seat 2 reaches the predetermined position on the sheet transfer path and the timing at which the sheet 2 leaves the predetermined position on the sheet transfer path based on the detection result of the microphone 70. To decide. Further, the seat transfer control unit 204 determines the occurrence of jam on the seat 2 based on the detection result of the microphone 70. The sheet transfer control unit 204 controls the transfer of the sheet 2 based on the determination result of the occurrence of jam in the sheet 2.

As shown in FIG. 5, different values are used for the first reference value, the second reference value, and the third reference value in the flowchart of FIG. 8 between the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72. Here, by setting each reference value so that the first reference value ≤ the third reference value <the second reference value, the optimum timing calculation can be performed. In this embodiment, when a positive judgment is made in the judgment process of S526, "the tip of the sheet 2 cannot be detected", and when a positive judgment is made in the judgment process of S528, "the tip of the sheet 2 can be detected". It is. " These determination processes may be changed depending on the configuration of the main body of the image forming apparatus 100 and the position of the resist section sound generating mechanism 71 for detecting the sheet 2 on the sheet transport path. For example, since there is a concern that the sheet 2 may wind around the fuser 13 in the vicinity of the fuser 13, if a positive judgment is made in the determination process of S528, it may be said that "the tip of the sheet 2 cannot be detected".

Further, in order to detect the arrival timing of the seat 2 by sound more accurately, the sampling frequency (sampling cycle) of sound detection may be increased only during the above sound detection period. By switching the sampling frequency, the sound detection accuracy can be improved only during the required period during the transportation of the sheet 2, and the delay in sound detection can be reduced. The sheet transport control unit 204 increases the sampling frequency when the microphone 70 detects sound at the start timing of the sound detection period, and sets the sampling frequency when the microphone 70 detects sound at the end timing of the sound detection period. It may be made smaller. In this way, the sheet transport control unit 204 may switch the sampling frequency when the microphone 70 detects sound at a predetermined timing. Further, the conversion unit 206 may perform such switching control. Also, sheet 2
By increasing the sound detection accuracy only during the required period during transportation, the sound detection processing load of the sheet transfer control unit 204 can be increased only when necessary, and the processing load of the engine control unit 203 that processes the entire print processing can be suppressed. can.

Further, in order to prevent erroneous detection of sound detection, the sound detection level may be switched for each frequency of the sound detected by the microphone 70. For example, the frequency of the sound generated by the resist unit sound generation mechanism 71 and the frequency of the sound generated by the paper ejection unit sound generation mechanism 72 may be different frequencies. In this way, the frequency of the sound generated by one of the plurality of sound generation mechanisms may be different from the frequency of the sound generated by the other one of the plurality of sound generation mechanisms. The sheet transport control unit 204 may switch the frequency of the sound detected by the microphone 70 at each detection timing (predetermined timing). Further, the conversion unit 206 may perform such switching control.

In this embodiment, the reference value (reference threshold) for sound detection is changed according to the positions of the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 on the sheet transport path. That is, the reference value for sound detection is set according to the distance between the position of the microphone 70 and the position of the resist unit sound generation mechanism 71. Further, the reference value for sound detection is set according to the distance between the position of the microphone 70 and the position of the paper ejection unit sound generation mechanism 72. The sheet transfer control unit 204 compares the detection result of the microphone 70 with the reference value for sound detection, and controls the transfer of the sheet 2 based on the comparison result.

Not limited to the method of changing the reference value as described above, the reference value may be changed by the following method. The sound detection gain level depends on the distance between the position of the microphone 70 and the position of the resist section sound generation mechanism 71, and the distance between the position of the microphone 70 and the position of the output section sound generation mechanism 72. To switch. The volume generated by the resist section sound generation mechanism 71 and the volume generated by the paper ejection section sound generation mechanism 72 are normalized, and the volume gain (detection gain level) when the microphone 70 detects the sound at each sound detection timing. ) May be switched. In this way, the sheet transfer control unit 204 may switch the volume gain when the microphone 70 detects the sound at a predetermined timing.

In this embodiment, the seat transfer control unit 204 controls the transfer of the sheet 2 by detecting the timing of sound generation and controlling the determination of JAM detection of the sheet 2. The sheet transfer control unit 204 stops the transfer of the sheet 2 and changes the transfer speed, switches the sheet transfer path using the double-sided flapper 51, and starts the paper feed by the paper feed roller 102, based on the detection timing of the microphone 70. The transfer control of the sheet 2 such as the above may be performed. The sheet transfer control unit 204 determines the JAM detection of the sheet 2, stops the transfer of the sheet 2 and changes the transfer speed, switches the sheet transfer path using the double-sided flapper 51, and starts the paper feed by the paper feed roller 102. You may control at least one of them.

Further, in this embodiment, the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 are provided separately from the conventional sensor. By substituting the sound generated when the sheet 2 collides with the member during the transportation of the sheet 2, the installation of the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 may be omitted. The image forming apparatus 100 may include a register shutter mechanism as a skew correction unit that corrects the skew of the sheet 2. The register shutter mechanism is a member that improves the transportability of the seat 2 on the seat transport path. When the registration shutter mechanism is arranged on the seat transport path, a collision sound is generated when the seat 2 collides with the registration shutter mechanism. In order to correct the skew of the seat 2, the registration shutter mechanism is arranged long in the width direction of the seat 2, and a relatively loud sound is generated when the seat 2 and the registration shutter mechanism collide with each other. In this way, the transfer force of the sheet 2 is used, and the judgment control of JAM detection of the sheet 2 and the transfer control of the sheet 2 are performed based on the collision sound generated when the sheet 2 and the registration shutter mechanism collide with each other. Is also possible. Further, the resist section sound generation mechanism 71 and the paper discharge section sound generation mechanism 72 may be installed, and the registration shutter mechanism may be arranged on the sheet transport path. The resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 may have a register shutter mechanism.

As described above, according to the present embodiment, the transfer control of the seat 2 can be performed by sound detection by the microphone 70 instead of the conventional optical sensor such as a photo interrupter. Therefore, wiring to an optical sensor such as a photointerruptor or an optical sensor can be omitted, and cost reduction and miniaturization of the image forming apparatus 100 become possible. Since the timing at which the sheet 2 arrives at a predetermined position on the sheet transport path can be detected, the timing at which the sheet 2 arrives at a place where it is difficult to place a conventional optical sensor, such as near the fuser 13, is detected. be able to. Further, a sound generation mechanism (sound generation unit) different from the resist unit sound generation mechanism 71 and the paper discharge unit sound generation mechanism 72 may be arranged on the sheet transport path. That is, a plurality of sound generating mechanisms (sound generating units) may be arranged on the sheet transport path. Further, the installation of one of the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 may be omitted.

(Example 2)
In this embodiment, a configuration will be described in which the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 generate sound a plurality of times to control the transfer of the sheet 2. In this embodiment, the arrival timing of the sheet 2 is accurately detected by generating a plurality of sounds and eliminating accidental sounds generated outside the device or inside the device in the sound detection process. In this embodiment, the description of the same configuration as that of the first embodiment will be omitted. The configuration of the image forming apparatus 100, the hardware configuration, and the system configuration of the entire control unit of this embodiment are the same as those of the first embodiment.

The paper ejection section sound generation mechanism 72 of this embodiment will be described with reference to FIG. 9 (a) to 9 (c) are explanatory views of the paper ejection section sound generating mechanism 72, and show the positional relationship between the sheet 2 and the paper ejection section sound generating mechanism 72. FIG. 9A is a view of the state before the sheet 2 reaches the mechanical flag 73 of the paper ejection unit sound generation mechanism 72 from the horizontal direction (horizontal direction). FIG. 2B is a view of the state when the tip of the seat 2 reaches the mechanical flag 73 as viewed from the horizontal direction (horizontal direction). FIG. 2C is a view of a state when the sheet 2 is further conveyed after the tip of the sheet 2 reaches the mechanical flag 73, as viewed from the lateral direction (horizontal direction).

The paper ejection section sound generating mechanism 72 has a mechanical flag 73 and a sound generating section 82, and is arranged on the sheet transport path in the vicinity of the fuser 13. When the seat 2 is conveyed and reaches the mechanical flag 73, the mechanical flag 73 rotates around the rotation axis of the mechanical flag 73 by coming into contact with the seat 2. The rotation axis of the mechanical flag 73 is arranged on a bearing (not shown) of the main body of the image forming apparatus 100. The sound generating unit 82 is a member configured to generate a sound when it comes into contact with the mechanical flag 73. A part of the sound generating section 82 is composed of two leaf spring-shaped members, and when the mechanical flag 73 and the leaf spring-shaped members of the sound generating section 82 come into contact with each other, the sound generating section 82 generates a sound. It has become.

When the transfer of the seat 2 is completed, the mechanical flag 73 returns to the original position on the sheet transfer path (the position before the transfer of the sheet 2) by a spring (not shown). Therefore, when the rear end of the sheet 2 passes through the position of the paper ejection section sound generating mechanism 72 and the rear end of the sheet 2 no longer comes into contact with the mechanical flag 73, the mechanical flag 73 is the two leaf spring-like members of the sound generating member 74. Contact with. Therefore, the sound generating member 74 generates sound twice at the timing when the front end of the seat 2 reaches the mechanical flag 73 on the seat transport path and at the timing when the rear end of the seat 2 passes through the mechanical flag 73. In this way, the paper ejection section sound generation mechanism 72 generates a sound twice at the arrival timing of the front end of the sheet 2 and the arrival timing of the rear end of the sheet 2. Further, the resist section sound generation mechanism 71 has the same configuration as the paper ejection section sound generation mechanism 72, and the resist section sound generation mechanism 71 has a configuration at the arrival timing of the front end of the sheet 2 and the arrival timing of the rear end of the sheet 2. It is configured to generate sound twice. The resist section sound generating mechanism 71 is arranged on the sheet transport path between the resist roller 3 and the fixing device 13.

<Sound detection and sheet transfer control>
Next, the sheet transfer control performed by the sheet transfer control unit 204, which is a feature of this embodiment, will be described with reference to FIGS. 10 and 11. FIG. 10 is a diagram showing the volume level of the sound detected by the microphone 70 from the start of printing to the end of printing of one sheet 2. The horizontal axis of FIG. 10 indicates time, and the vertical axis of FIG. 10 indicates the volume level.

Here, the timings (a) to (h) of FIG. 10 are the same as the timings (a) to (h) of FIG. 5 of the first embodiment. Further, as in the first embodiment, the sheet transport control unit 204 performs the sound detection determination process in the period (sound detection period) before and after each of the timings (c), (d), (e) and (f). You may do so. Further, the sheet transfer control unit 204 sets the first time and the second time for the timings (c), (d), (e) and (f), respectively, and subtracts the first time from the second time. , Sound detection periods A, B, C and D may be set.

FIG. 11 is an enlarged view of the volume waveform at the timing (c) of FIG. 10, and shows a method of detecting the sheet arrival timing. FIG. 11A is a diagram showing a normal volume waveform when there is no noise sound from the outside, and the normal volume waveform has two peaks. In the case of the volume waveform of FIG. 11A, the sheet transport control unit 204 determines the sheet arrival timing T1 after detecting two volume peaks. The volume waveform of FIG. 11B has three peaks due to noise from the outside. Even in this case, a method of correctly determining the sheet arrival timing T1 will be described below.

The actual calculation of the sheet arrival timing T1 is performed in the order of the following processes (1) to (3). In the following processes (1) to (3), the timing T1 at which the tip of the sheet 2 reaches the position of the resist portion sound generating mechanism 71 is described. The same applies to the timing at which the rear end of the sheet 2 reaches the position of the resist portion sound generating mechanism 71 and the timing at which the front end or the rear end of the sheet 2 reaches the position of the paper ejection portion sound generating mechanism 72.

(1) Detection of volume peak When the volume exceeds a predetermined first reference value (first reference threshold value), the sheet transport control unit 204 sets the absolute time T1 when the volume exceeds the first reference value. It is stored in a storage unit such as RAM 509 and ROM 510. Next, after the volume exceeds a predetermined second reference value (second reference threshold) larger than the first reference value, and then the volume is less than or equal to the predetermined third reference value (third reference threshold) smaller than the second reference value. When becomes, the sheet transport control unit 204 detects the volume peak. Further, the sheet transfer control unit 204 stores the absolute time T3 when the volume exceeds the second reference value in the storage unit. The sheet transfer control unit 204 stores the absolute time T1 in the storage unit as T1A and T1B for each volume peak, and stores the absolute time T3 in the storage unit as T3A and T3B for each volume peak. The sheet transport control unit 204 repeats these processes every time the volume peaks are detected until the second time elapses or until it is determined that the two volume peaks have been detected in the following process (2).

(2) Peak selection determination The sheet transport control unit 204 confirms each interval of T3A, T3B ... Stored for each volume peak in the above process (1) for each volume peak. When the difference time of two absolute times T3 out of the plurality of absolute times T3 is within a preset predetermined time range, the sheet transport control unit 204 determines that two volume peaks have been detected. That is, when the difference time between the two absolute times T3 is equal to or longer than the first predetermined time and equal to or less than the second predetermined time larger than the first predetermined time, the sheet transport control unit 204 sets two volume peaks. Judge that it has been detected. In FIG. 11A, the sheet transport control unit 204 determines that the difference time of T3B-T3A is within a predetermined time range, and determines T1A as the sheet arrival timing T1. In FIG. 11B, the sheet transfer control unit 204 determines that the difference time of T3B-T3A and the difference time of T3C-T3A are not within the predetermined time range. Further, in FIG. 11B, the sheet transport control unit 204 determines that the difference time of T3C-T3B is within a predetermined time range, and determines T1B as the sheet arrival timing T1. Since the predetermined time varies depending on the configuration of the paper ejection section sound generating mechanism 72 and the configuration of the resist section sound generating mechanism 71 shown in FIG. 9, it is preferable to set the predetermined time for each configuration.

(3) Correction of Sound Wave Arrival Time Similar to the first embodiment, the timing T at which the tip of the sheet 2 actually reaches the resist portion sound generation mechanism 71 is represented by T = T1-T2.

FIG. 12 is a flowchart for determining the timing at which the tip of the sheet 2 reaches the position of the resist portion sound generation mechanism 71. First, the seat transfer control unit 204 determines whether the first time has elapsed from the start of transfer of the sheet 2 (S621). When the first time has elapsed from the start of the transfer of the sheet 2 (S621: Yes), the sheet transfer control unit 204 starts the sound detection (S622) and performs the process of S623. The sheet transfer control unit 204 determines whether the second time has elapsed from the start of transfer of the sheet 2 (S623). When the second time has elapsed from the start of the transfer of the sheet 2 (S623: Yes), the sheet transfer control unit 204 performs the process of S634.

When the second time has not passed from the start of the transfer of the sheet 2 (S623: No), the sheet transfer control unit 204 performs the volume peak detection process as in the first embodiment to determine whether the volume peak has been detected. Judgment (S624). The sheet transfer control unit 204 repeats each process of S623 and S624 until the volume peak is detected. When the sheet transport control unit 204 detects a volume peak (S624: Yes), the number of times the volume peak is detected is set to +1 (S625).

The sheet transfer control unit 204 stores the absolute time T1 when the volume exceeds the first reference value in the storage unit (S626). The sheet transfer control unit 204 stores the absolute time T3 when the volume exceeds the second reference value in the storage unit (S627). The sheet transport control unit 204 determines whether or not the volume peak has been detected twice or more (S628). If the number of times the volume peak is detected is less than 2 (S628: No), the process returns to S623, and the sheet transport control unit 204 performs the process of S623 again. When the number of times of detecting the volume peak is 2 times or more (S628: Yes), the sheet transport control unit 204 performs the process of S629.

The sheet transfer control unit 204 confirms the time difference of the absolute time T3 for each volume peak, and determines whether the time difference is within the preset predetermined time range (S629). When the difference time between the two selected absolute times T3 out of the plurality of absolute times T3 is within the preset predetermined time range (S629: Yes), the sheet transport control unit 204 performs the process of S630. conduct. If the difference time is not within the predetermined time range (S629: No), the process returns to S623, and the sheet transfer control unit 204 performs the process of S623 again. The sheet transport control unit 204 determines that the volume peak satisfying the predetermined reference has been detected twice (S630). The sheet transfer control unit 204 determines the absolute time T1 of the first volume peak among the two volume peaks satisfying the predetermined reference as the sheet arrival timing T1 (S631). The seat transfer control unit 204 performs a correction calculation (timing correction calculation) for the seat arrival timing T1 (S632). After that, the sheet transport control unit 204 ends the sound detection by the microphone 70 when the tip of the sheet 2 reaches the position of the resist unit sound generation mechanism 71 (S633).

When the second time has elapsed from the start of the transfer of the sheet 2 (S623: Yes), the sheet transfer control unit 204 performs the process of S634. That is, if the detection of the volume peaks at predetermined time intervals is not completed, if only one volume peak is detected, or if no volume peak is detected, the sheet transport control unit 204 sets the sheet transfer control unit 204. The process of S634 is performed. In these cases, the sheet transport control unit 204 determines that the volume cannot be detected (S634). Since the tip of the seat 2 cannot be detected, the seat transport control unit 204 ends the sound detection without determining the seat arrival timing T1 (seat arrival timing T1 = 0 (error)) (S633).

A plurality of the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72 are provided at least at one of the timings when the sheet 2 reaches a predetermined position on the sheet transport path and when the sheet 2 separates from the predetermined position on the sheet transport path. Generates the sound of times. The microphone 70 detects a plurality of sounds generated by the resist section sound generating mechanism 71 and the paper ejection section sound generating mechanism 72. Here, in the present embodiment, the seat arrival timing T1 is determined by generating two sounds, but the seat arrival timing T1 is determined by generating three or more sounds. May be adopted. Further, in this embodiment, the predetermined time interval for sound generation changes for each configuration of the resist part sound generation mechanism 71 and the paper discharge part sound generation mechanism 72, but when the transport speed of the sheet 2 changes, the mechanical flag is changed. The movements of 72 and 73 change, and the time interval of sound generation changes. Therefore, a configuration may be adopted in which the time interval for sound generation is changed for each transport speed of the sheet 2.

Further, in the present embodiment, the frequencies of the two sounds generated by the sound generating unit 82 may be changed by adjusting the material and the length of the leaf spring-shaped member of the sound generating unit 82 of FIG. Therefore, the frequencies of the sounds generated by the resist unit sound generation mechanism 71 and the paper discharge unit sound generation mechanism 72 may be different from each other. Then, when the sheet transport control unit 204 detects the peaks of the two sounds, the peaks of the sounds may be determined including the frequency characteristics of the detected sounds, and the arrival timing T1 of the sheet 2 may be determined.

As described above, according to the present embodiment, the transfer control of the sheet 2 is surely performed by generating a plurality of sounds during the transfer of the sheet 2 and preventing erroneous detection of the arrival timing of the sheet 2. Can be done.

2 ... Sheet, 70 ... Microphone, 71 ... Resist section sound generating mechanism, 72 ... Paper ejection section sound generating mechanism, 74 ... Sound generating section, 100 ... Image forming device, 101 ... Cassette paper feed tray, 102 ... Paper feed roller, 204 ... Sheet transfer control unit

Claims (13)

In an image forming apparatus that forms an image on a recording material
A loading unit for loading the recording material and
A paper feeding unit that feeds the recording material from the loading unit to the transport path, and a paper feeding unit.
A sound generating unit that generates sound at at least one timing when the recording material reaches a predetermined position on the transport path and when the recording material is separated from the predetermined position.
A sound detection unit that detects the sound generated by the sound generation unit, and
A control unit that controls the transport of the recording material based on the detection result of the sound detection unit, and
An image forming apparatus comprising. The image forming apparatus according to claim 1, wherein the sound generating unit generates sound by utilizing the conveying force of the recording material. The control unit detects the peak of the sound generated by the sound generating unit based on the detection result of the sound detecting unit, and the timing at which the recording material reaches the predetermined position and the recording based on the peak of the sound. The image forming apparatus according to claim 1 or 2, wherein at least one of the timings at which the material leaves the predetermined position is determined. Claims 1 to 3, wherein the control unit determines the occurrence of jam of the recording material based on the detection result, and controls the transport of the recording material based on the determination result of the occurrence of the jam. The image forming apparatus according to any one of the above. Based on the detection result, the control unit stops the transport of the recording material, changes the transport speed of the recording material, switches the transport path, and starts the paper feed by the paper feed unit. The image forming apparatus according to any one of claims 1 to 4, wherein the image forming apparatus is controlled. The control unit compares the detection result with the reference value, and controls the transport of the recording material based on the comparison result.
The reference value according to any one of claims 1 to 5, wherein the reference value is set according to the distance between the position of the sound generating unit and the position of the sound detecting unit. Image forming device. The image forming apparatus according to any one of claims 1 to 6, wherein the control unit switches a sampling cycle when the sound detection unit detects a sound at a predetermined timing. The image forming apparatus according to any one of claims 1 to 7, wherein a plurality of the sound generating units are arranged in the transport path. The frequency of the sound generated by one of the plurality of sound generators is different from the frequency of the sound generated by the other one of the plurality of sound generators.
The image forming apparatus according to claim 8, wherein the control unit switches the frequency of the sound detected by the sound detection unit at a predetermined timing. The image forming apparatus according to any one of claims 1 to 9, wherein the control unit switches a volume gain when the sound detection unit detects a sound at a predetermined timing. Any one of claims 1 to 10, wherein the sound generated by the sound generating unit is a collision sound when the recording material collides with the skew correction unit that corrects the skew of the recording material. The image forming apparatus according to the section. The sound generating unit generates a plurality of sounds at at least one timing when the recording material reaches a predetermined position on the transport path and when the recording material is separated from the predetermined position.
The image forming apparatus according to any one of claims 1 to 11, wherein the sound detecting unit detects a plurality of sounds generated by the sound generating unit. The image forming apparatus according to claim 12, wherein the frequencies of a plurality of sounds generated by the sound generating unit are different from each other.

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