JP2020154133A - Image formation apparatus - Google Patents

Abstract

To start the calibration of a detection member earlier and start the printing earlier.SOLUTION: An image formation apparatus comprises: a rotary member; a detection object member which is rotated following the rotation of the rotary member; a detection member which detects the detection object member to generate the sensor output; and a calibration processing unit which reads the sensor output of the detection member to perform the calibration of the detection member. The detection object member is deployed in a movable manner to take the first and second operation positions. The calibration processing unit performs the first calibration in such a state that the detection object member is placed at the first operation position before the rotation of the rotary member is started, and performs the second calibration in such a state that the detection object member is placed at the second operation position after the rotation of the rotary member is started.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming apparatus.

Conventionally, in an image forming apparatus such as an electrophotographic printer, a copying machine, a facsimile, or a compound machine, for example, in a printer, the surface of a photoconductor drum uniformly charged by a charging roller is exposed by an LED head to be static. An electro-latent image is formed, the electrostatic latent image is developed by a developer to form a toner image, and the toner image is transferred to paper by a transfer roller and fixed in a fuser to form an image on paper. Is formed and printing is performed.

A fixing roller and a pressure roller are arranged in the fixing device, and the toner image transferred to the paper is heated by the fixing roller and pressed by the pressure roller to be fixed on the paper.

Then, the fixing roller is rotated by driving a fixing motor as a driving unit for fixing, and the rotation speed is controlled based on the number of rotations detected by the rotation sensor as a detection member (for example, patent). See Document 1.).

In this type of printer, warm-up is started when the power is turned on, the fixing roller is heated in the fixing device, the fixing motor is driven, and the rotation sensor is calibrated.

In the calibration, first, the white part formed on the rotating plate of the rotation sensor is calibrated, and the value of the calibration by the white part is used to calibrate the white part and the black part of the rotating plate. Is done.

Japanese Unexamined Patent Publication No. 2014-106460

However, in the conventional printer, the fixing motor is not driven and the rotating plate does not rotate until the temperature of the fixing roller reaches a predetermined value.

Therefore, the calibration is started later, and the printing is started later by that amount.

An object of the present invention is to provide an image forming apparatus capable of solving the problems of the conventional printer, calibrating the detection member early, and starting printing early.

Therefore, in the image forming apparatus of the present invention, the rotating member that is rotated by driving the driving unit, the detected member that is rotated by the rotation of the rotating member, and the detected member are opposed to each other. It has a detection member that is arranged to detect a member to be detected and generates a sensor output, and a calibration processing unit that reads the sensor output of the detection member and calibrates the detection member.

Then, the detected member is movably arranged and takes the first and second operating positions.

Further, the calibration processing unit performs the first calibration based on the sensor output of the detection member in a state where the member to be detected is placed in the first operation position before the rotation of the rotating member is started. After the rotation of the rotating member is started, the second calibration is performed based on the sensor output of the detection member in a state where the member to be detected is placed in the second operating position.

According to the present invention, in the image forming apparatus, a rotating member that is rotated by driving a driving unit, a member to be detected that is rotated with the rotation of the rotating member, and the member to be detected are opposed to each other. It has a detection member that is arranged to detect a member to be detected and generates a sensor output, and a calibration processing unit that reads the sensor output of the detection member and calibrates the detection member.

Then, the detected member is movably arranged and takes the first and second operating positions.

Further, the calibration processing unit performs the first calibration based on the sensor output of the detection member in a state where the member to be detected is placed in the first operation position before the rotation of the rotating member is started. After the rotation of the rotating member is started, the second calibration is performed based on the sensor output of the detection member in a state where the member to be detected is placed in the second operating position.

In this case, the calibration processing unit performs the first calibration with the detected member placed in the first operating position before the rotation of the rotating member is started, and the rotation of the rotating member is started. After that, since the second calibration is performed with the member to be detected placed in the second operating position, the calibration can be started earlier and the printing can be started earlier.

It is a control block diagram of the printer in embodiment of this invention. It is a conceptual diagram of the printer in embodiment of this invention. It is the schematic of the fuser in embodiment of this invention. It is a front view of the rotating plate in embodiment of this invention. It is a control block diagram of the rotation detection control part in embodiment of this invention. It is a vertical cross-sectional view of the fuser in embodiment of this invention. It is a figure which shows the nip position of the lever in embodiment of this invention. It is a figure which shows the release position of the lever in embodiment of this invention. It is a figure which shows the gear train in embodiment of this invention. It is a figure which shows the relationship between the release cam and the lever in embodiment of this invention. It is a figure which shows the state which the pressure roller in the embodiment of this invention is pressed against a fixing roller. It is a figure which shows the state which the pressure roller in the embodiment of this invention is separated from a fixing roller. It is a front view of the rotating plate and the reflection sensor in embodiment of this invention. It is a side view of the rotating plate and the reflection sensor in embodiment of this invention. It is a figure which shows the relationship between the rotating plate and a reflection sensor when the lever in an embodiment of this invention is placed in a release position. It is a figure which shows the relationship between the rotating plate and a reflection sensor when a lever is placed at a nip position in embodiment of this invention. It is a 1st flowchart which shows the operation of the printer in embodiment of this invention. 2 is a second flowchart showing the operation of the printer according to the embodiment of the present invention. It is a figure which shows the subroutine of the precalibration processing in embodiment of this invention. It is a figure which shows the subroutine of post-calibration processing in embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a printer as an image forming apparatus will be described.

FIG. 2 is a conceptual diagram of a printer according to an embodiment of the present invention.

In the figure, 10 is a printer, Cs is a housing, and Bd is a printer main body, that is, a device main body.

The printer 10 is removably arranged with respect to the housing Cs, and feeds the paper cassette 12 as a medium accommodating portion for accommodating the paper P as a medium and the paper P into the paper conveying path Rt1 as the medium conveying path. The paper feed section 14 is arranged on the downstream side of the paper feed section 14 in the paper transport path Rt1, and is arranged on the downstream side of the transport rollers m1 and m2 for transporting the paper P and the transport rollers vs. m2 in the paper transport path Rt1. The image forming portion Q1 that forms a toner image as a developer image on the paper P is detachably arranged on the paper P on the downstream side of the image forming portion Q1 in the paper transport path Rt1 with respect to the apparatus main body Bd. The fixing device 16 as a fixing device for fixing the image, the paper ejection sensor s4 arranged on the downstream side of the fixing device 16 on the paper transport path Rt1, and the paper ejection sensor s4 arranged on the downstream side of the paper ejection sensor s4 on the paper transport path Rt1. A transport roller pair m3 that transports the paper P, a paper discharge roller pair m4 that is arranged downstream of the transport roller pair m3 in the paper transport path Rt1 and discharges the paper P to the outside of the apparatus main body Bd, and formed on the upper part of the housing Cs. It is provided with a stacker 18 or the like on which the paper P discharged by the paper ejection roller vs. m4 is loaded.

The paper cassette 12 includes a paper detection sensor s1 that detects the paper P in the paper cassette 12, and a pickup roller 21 that is arranged so as to be in pressure contact with the paper P and feeds out the paper P. In the present embodiment, as the paper P, high-quality paper, recycled paper, glossy paper, matte paper, OHP (Over Head Projector) film or the like having a predetermined size for forming an image is used.

The paper feed unit 14 rotates in the direction opposite to that of the hop sensor s2 for detecting the paper being fed, the paper feed roller 23 for supplying the fed paper P to the paper transport path Rt1, and the paper feed roller 23. A retard roller 24 is provided together with the paper feed roller 23 so as to sandwich the paper P and separate the sheets one by one.

The transport roller pair m1 includes a transport roller ma1 that is rotated by a paper transport motor M1 (FIG. 1) described later as a drive unit for media transport, and a pinch roller mb1 that is rotated around the transport roller ma1. Be prepared. Further, the transfer roller pair m2 includes a resist roller ma2 that is rotated by the paper transfer motor M1 and a pinch roller mb2 that is rotated around the resist roller ma2.

The image forming unit Q1 refers to the writing position sensor s3 arranged on the downstream side of the transport roller pair m2 in the paper transport path Rt1 and the device main body Bd on the downstream side of the writing position sensor s3 in the paper transport path Rt1. The image forming unit 26 is detachably arranged, and is arranged above the photoconductor drum 28 as an image carrier of the image forming unit 26 so as to face the photoconductor drum 28, and is exposed to light corresponding to the image information. An LED head 29 as an exposure device for irradiating the body drum 28, a transfer roller 31 as a transfer member arranged below the photoconductor drum 28 so as to face the photoconductor drum 28, and the like are provided.

The image forming unit 26 includes a toner cartridge 33 as a developer accommodating portion and a main body portion 34 that supports the toner cartridge 33 downward, and the toner cartridge 33 accommodates toner as a developer. The main body 34 includes the photoconductor drum 28, a charging roller 36 as a charging device, a developing roller 38 as a developer carrier, a supply roller 39 as a supply member, a developing blade 41 as a developer layer regulating member, and cleaning. A cleaning blade 43 or the like as a member is provided. The charging roller 36, the developing roller 38, and the cleaning blade 43 are pressed against the photoconductor drum 28 with a predetermined pressing force, and the developing blade 41 and the supply roller 39 are pressed against the developing roller 38 with a predetermined pressing force. The toner cartridge 33 is formed with a waste toner accommodating chamber 33a for accommodating the collected waste toner.

The photoconductor drum 28 is rotatably arranged, rotated in the arrow direction (clockwise direction), has a cylindrical shape, and transports a photoconductive layer and charges to a conductive support made of aluminum or the like. It is formed by coating a photosensitive layer composed of layers.

The charging roller 36 has a cylindrical shape and is formed by coating a conductive metal shaft with a semi-conductive rubber such as silicone, and is charged by an image forming unit power supply 55 (FIG. 1) described later. When a voltage is applied, a predetermined voltage is applied to the photoconductor drum 28 to uniformly charge the photoconductor drum 28.

The LED head 29 includes a plurality of LEDs (light emitting diodes), a lens array, and an LED driving element (not shown), exposes the photoconductor drum 28 based on image information, and creates an electrostatic latent image on the surface of the photoconductor drum 28. Form.

The developing roller 38 has a cylindrical shape and is formed by coating a conductive metal shaft with semi-conductive urethane rubber or the like, and a developing voltage is applied by an image forming unit power supply 55. Toner is adhered to the electrostatic latent image formed on the surface of the photoconductor drum 28 (the electrostatic latent image is developed) to form the toner image.

The supply roller 39 has a cylindrical shape and is formed by coating a conductive metal shaft with sponge rubber, and a supply voltage is applied to the developing roller 38 by the image forming unit power supply 55. Supply toner.

The developing blade 41 is made of stainless steel or the like having a plate-like shape, scrapes off the toner on the surface of the developing roller 38, and forms a uniform toner layer on the surface of the developing roller 38.

The cleaning blade 43 is made of a rubber material or the like having a plate-like shape, and scrapes and removes the toner remaining on the photoconductor drum 28 after the toner image on the photoconductor drum 28 is transferred to the paper P.

The transfer roller 31 transfers the toner image formed on the photoconductor drum 28 to the paper P by applying a transfer voltage by the image forming unit power supply 55.

The fixing device 16 is added to the housing Hs as a fixing roller 44 as a first fixing member and as a rotating member for heating, and as a second fixing member and as a rotating member for pressurization. A pressure roller 45, a fixing belt 46 (FIG. 3) described later as a third fixing member and a belt member, and the like are provided, and the toner image is fixed to the paper P by heating and pressurizing the paper P. Let me.

The transport roller pair m3 includes a transport roller ma3 that is rotated by a paper transport motor M1 described later, and a pinch roller mb3 that is rotated around the transport roller ma3. Further, the paper ejection roller pair m4 includes a paper ejection roller ma4 that is rotated by the paper transport motor M1 and a pinch roller mb4 that is rotated around the paper ejection roller ma4.

Next, the operation of the printer 10 will be described.

The printer 10 is connected to a host computer (not shown) as a host device by a cable or wirelessly. When the printer 10 receives print data from the host computer and receives a print request, a pickup motor (not shown) is driven, the pickup roller 21 is rotated, the paper P is fed out from the paper cassette 12, and the paper feed unit 14 feeds the paper P. The sheets are separated one by one and sent to the paper transport path Rt1. At this time, depending on whether or not the hop sensor s2 detects the paper P, it is determined by the pickup roller 21 whether or not the paper P is normally fed, and if the paper P is not normally fed, the pickup motor is driven again. Will be done.

Then, the paper P sent to the paper transport path Rt1 is sandwiched by the transport rollers vs. m1 and supplied to the transport rollers vs. m2 as the transport rollers vs. m1 rotate. At this time, the rotation of the paper P is blocked by a clutch (not shown), and the paper P is abutted against the stopped transport roller pair m2 to correct the skew generated when the paper P is fed to the paper transport path Rt1. .. Subsequently, the paper P is fed to the image forming unit Q1 with the rotation of the transfer roller vs. m2.

The photoconductor drum 28 is rotated by one or more rotations before the paper P reaches the image forming unit Q1.

Then, when the front end of the paper P reaches the writing position sensor s3, the writing position sensor s3 detects (turns on) the paper P. Then, when a certain time elapses after the writing position sensor s3 detects the paper P, the LED head 29 exposes the photoconductor drum 28.

In the image forming unit Q1, the photoconductor drum 28 is rotated in the direction of the arrow, and the surface is uniformly charged by the charging roller 36. Subsequently, when the image data generated by editing the print data is sent to the LED head 29, the LED head 29 exposes the photoconductor drum 28 by irradiating the photoconductor drum 28 with light according to the image data. , An electrostatic latent image is formed on the surface of the photoconductor drum 28.

Then, the developing roller 38 develops the electrostatic latent image by adhering the toner to the electrostatic latent image, and forms the toner image on the photoconductor drum 28.

Subsequently, the toner image on the photoconductor drum 28 is transferred to the paper P by the transfer voltage applied to the transfer roller 31.

The paper P on which the toner image is transferred is charged to a positive polarity by the transfer roller 31 and sent to the fixing device 16, where the nip portion formed by the fixing roller 44 and the fixing belt 46 is formed in the fixing device 16. As it passes, it is heated by the fixing roller 44 and pressed by the pressure roller 45 to fix the toner image. At this time, the toner remaining on the photoconductor drum 28 is scraped off by the cleaning blade 43, recovered by a recovery mechanism (not shown), and stored in the waste toner storage chamber 33a formed in the toner cartridge 33.

After the paper output sensor s4 detects (turns on) the paper P, the paper P on which the toner image is fixed is conveyed by the transfer roller vs. m3, and is discharged to the outside of the apparatus main body Bd by the paper discharge roller vs. m4. , Loaded on the stacker unit 18.

Next, the fuser 16 will be described.

FIG. 3 is a schematic view of the fuser according to the embodiment of the present invention, and FIG. 4 is a front view of the rotating plate according to the embodiment of the present invention.

In the figure, 16 is a fixing device, 44 is a rotatably arranged fixing roller, and 45 is rotatably arranged below the fixing roller 44 with respect to the fixing roller 44 as the fixing roller 44 rotates. The pressurizing roller 46, which is rotated in the same manner, surrounds the pressurizing roller 45 and is arranged so as to travel freely. The rotating plate s5 as a member to be detected, which is rotated along with the rotating plate, s5 is supported by the housing Hs (FIG. 2), and the thermista ht as a temperature detecting unit arranged in contact with or close to the fixing roller 44 is It is a heater as a heating body that is arranged so as to extend in the axial direction in the fixing roller 44. In this embodiment, a halogen heater is used as the heater ht.

The fixing roller 44 has a cylindrical shape, and a core metal as a substrate made of an iron tube having a diameter of 30 [mm] is coated with an elastic layer made of silicone rubber having a thickness of 1 [mm]. It is formed by doing.

The pressure roller 45 has a cylindrical shape, has heat resistance to a core metal as a base body made of an iron metal solid shaft having a diameter of 20 [mm], and has a thickness made of porous material. It is formed by coating an elastic layer made of 1 [mm] sponge.

Further, the pressure roller 45 is pressed against the fixing roller 44 via the fixing belt 46 to form a nip portion between the fixing roller 44 and the fixing belt 46.

The fixing roller 44 is rotated by driving a fixing motor M2 (FIG. 1), which will be described later, as a driving unit for fixing, whereby the fixing belt 46 is driven, and the fixing belt 46 is driven along with the running of the fixing belt 46. The pressurizing roller 45 is rotated around.

The paper P transported from the image forming unit Q1 through the paper transport path Rt1 is sent to the nip portion between the fixing roller 44 and the fixing belt 46. In the figure, tn is a toner that forms a toner image.

The rotating plate 47 has a circular shape, is rotatably arranged with respect to the housing Hs around the shaft sh1, and is placed on a surface facing the reflection sensor 66 (FIG. 1) described later as a detection member. The irradiation surface Sa is formed. The irradiation surface Sa is formed in the inner ring portion near the axis sh1 and is formed on the outer side in the radial direction from the first irradiation region Ar1 having a cylindrical shape and the first irradiation region Ar1 and has an annular shape. It is composed of a second irradiation region Ar2 having. Then, a white portion q1 as a first color portion is formed in the first irradiation region Ar1 over the entire area in the circumferential direction, and 4 as a second color portion having a fan-shaped shape in the second irradiation region Ar2. The white portion q2 and the four black portions q3 as the third color portion are formed so as to be alternately adjacent to each other in the circumferential direction. The white portions q1 and q2 are formed by communicating with each other.

Next, the control device of the printer 10 will be described.

FIG. 1 is a control block diagram of a printer according to an embodiment of the present invention, and FIG. 5 is a control block diagram of a reflection sensor according to an embodiment of the present invention.

In the figure, 51 is a control unit that controls the entire printer 10 (FIG. 2), 52 is a ROM as a first storage device, 53 is a RAM as a second storage device, and 54 is an operation panel. The control unit 51 includes a CPU (not shown) as an arithmetic unit, and performs various processes based on a program recorded in the ROM 52. In addition to the program, various set values and the like are recorded in the ROM 52, and various data are temporarily recorded in the RAM 53. The operation panel 54 includes an LED screen (not shown) as a display unit for displaying the status of the printer 10, switches and keys (not shown) as an operation unit for the operator to input instructions to the printer 10. When the operation panel 54 is formed by a touch panel, the display unit also functions as an operation unit.

Further, 29 is an LED head, 55 is an image forming unit power supply, M1 is a paper transport motor, 57 is a paper transport motor power supply that supplies power to the paper transport motor M1, M2 is a fixing motor, and 61 is power to the fixing motor M2. Is a fixing motor power supply, s3 is a writing position sensor, s4 is a paper ejection sensor, ht is a heater, 64 is a heater power supply that supplies power to the heater ht, s5 is a thermista, and 66 is a reflection sensor.

The paper transport motor M1 is driven to rotate the transport roller pairs m1 to m3 and the paper discharge roller m4. The paper transport path Rt1 is provided with a clutch (not shown) that interrupts power transmission to the transport rollers m1 to m3 and the transport rollers ma1, ma3, the resist roller ma2, and the paper discharge roller ma4 of the paper discharge roller m4. ..

The reflection sensor 66 is an optical sensor that detects the rotating plate 47 (FIG. 3) and generates a sensor output. The reflection sensor 66 includes a light amount adjusting unit 71, a light emitting unit 72, and a light receiving unit 73, and the light amount adjusting unit 71 emits light. The amount of light generated by the unit 72 is adjusted, the light emitting unit 72 generates light and irradiates the rotating plate 47, and the light receiving unit 73 receives the light reflected by the rotating plate 47, that is, the reflected light. , Generates a sensor output and sends it to the control unit 51. The sensor output of the light receiving unit 73 can be represented by a voltage obtained by photoelectrically converting the amount of reflected light.

The control unit 51 includes a print control unit Pr1, a motor control unit Pr2, a paper position detection unit Pr3 as a medium position detection unit, a heating control unit Pr4, a rotation detection control unit Pr5, and the like.

The print control unit Pr1 is connected to the LED head 29 and the image forming unit power supply 55, the photoconductor drum 28 is exposed by the LED head 29, and the transfer roller 31 is subjected to about +3000 [V] by the image forming unit power supply 55. A transfer voltage is applied, a charging voltage is applied to the charging roller 36, a developing voltage is applied to the developing roller 38, a supply voltage is applied to the supply roller 39, a toner image is formed on the photoconductor drum 28, and the toner image is formed. Transfer to paper P.

The motor control unit Pr2 is connected to the paper transport motor power supply 57 and the fixing motor power supply 61, and controls the drive of the paper transport motor M1 and the fixing motor M2.

The paper position detection unit Pr3 is connected to the writing position sensor s3 and the paper ejection sensor s4, reads the sensor output, and detects the position of the paper P.

The heating control unit Pr4 is connected to the heater power supply 64 and the thermistor s5, functions as a temperature control processing unit, turns on / off the heater ht based on the temperature of the fixing roller 44 detected by the thermistor s5, and turns on / off the heater ht. Is controlled so that the target fixing temperature is reached. Further, the heating control unit Pr4 functions as a warm-up processing unit when the power of the printer 10 is turned on, and by heating a predetermined member, in the present embodiment, the fixing roller 44, the printer 10 Warm up.

The rotation detection control unit Pr5 reads the sensor output of the reflection sensor 66, functions as a rotation detection processing unit based on the sensor output, detects the rotation of the rotating plate 47, and functions as a calibration processing unit. The reflection sensor 66 is calibrated.

That is, the rotation detection control unit Pr5 reads the sensor output of the light receiving unit 73, and the sensor output of the light receiving unit 73 when the light emitting unit 72 irradiates the white portions q1 and q2 with light, and the light emitting unit 72 emits light to the black portion. The rotation of the rotating plate 47 is detected based on the sensor output of the light receiving unit 73 when the q3 is irradiated. Then, the rotation detection control unit Pr5 determines that an abnormality has occurred in the fuser 16 when the rotation of the rotating plate 47 is not detected during printing and the pressurizing roller 45 is not rotating, and the motor control unit Pr2 , The heating control unit Pr4 and the like are notified, the paper transport motor M1 and the fixing motor M2 are stopped, and the heater ht is turned off.

Further, the rotation detection control unit Pr5 calibrates the reflection sensor 66 before detecting the rotation of the rotation plate 47, and corrects the detection error of the rotation of the rotation plate 47 caused by the manufacturing error of the reflection sensor 66, aged deterioration, and the like. To do.

Therefore, in the rotation detection control unit Pr5, the light receiving unit 73 rotates with the sensor output when the light receiving unit 73 receives the reflected light of the white portions q1 and q2 of the rotating plate 47 as the white level as the first output level. The sensor output when the black portion q3 of the plate 47 receives the reflected light is read as the black level as the second output level, so that the difference voltage δV, which is the difference between the white level and the black level, becomes the specified value Vs or more. In addition, the amount of light generated by the light emitting unit 72 is adjusted.

By the way, in the fuser 16, the pressurizing roller 45 can be pressed against the fixing roller 44 or separated from the fixing roller 44, and for that purpose, the release described later on the fixing roller 16 The mechanism Mz (FIG. 7) is arranged.

Next, the release mechanism Mz will be described.

FIG. 6 is a vertical cross-sectional view of the fuser according to the embodiment of the present invention, FIG. 7 is a diagram showing the nip position of the lever according to the embodiment of the present invention, and FIG. 8 shows the release position of the lever according to the embodiment of the present invention. 9 is a diagram showing a gear train according to an embodiment of the present invention, FIG. 10 is a diagram showing a relationship between a release cam and a lever according to an embodiment of the present invention, and FIG. 11 is a diagram showing an addition in the embodiment of the present invention. FIG. 12 is a diagram showing a state in which the pressure roller is pressed against the fixing roller, and FIG. 12 is a diagram showing a state in which the pressure roller in the embodiment of the present invention is separated from the fixing roller.

In the figure, 16 is a fuser, Hs is a housing, 44 is a fixing roller, 45 is a pressurizing roller, 47 is a rotating plate, 66 is a reflection sensor, ht is a heater, s5 is a thermistor, and Mz is a release mechanism. The release mechanism Mz includes a pair of levers 75, a release cam 78 as a release member and a pressing member, a spring 81 as an urging member, a fixing motor M2 (FIG. 1), and a gear train Gt as a rotation transmission system. It consists of a shaft sh3 and the like.

The fixing roller 44 is rotatably supported with respect to the housing Hs via bearings br1 arranged at both ends. Further, the lever 75 is centered on the shaft sh2 with respect to the housing Hs so that the pressure roller 45 can be pressed against the fixing roller 44 or separated from the fixing roller 44 in the housing Hs. It is swingably supported, and the pressure roller 45 is rotatably supported with respect to the lever 75 via bearings br2 arranged at both ends.

The lever 75 is swung by driving the fixing motor M2 in the forward direction or the reverse direction. That is, when the fixing motor M2 is driven in the forward direction, as shown in FIG. 7, the lever 75 is placed at the nip position, the pressurizing roller 45 is pressed against the fixing roller 44, and the fixing motor M2 is pushed in the opposite direction. When driven, the lever 75 is placed in the release position and the pressurizing roller 45 is separated from the anchoring roller 44, as shown in FIG.

Therefore, an engaging portion 76 is formed at the upper end of the lever 75 so as to project upward, and the release cam 78 is centered on the shaft sh3 so as to face the surface Sb of the engaging portion 76 on the shaft sh2 side. It is arranged so as to be swingable. Further, the spring 81 is arranged in contact with the surface Sc of the engaging portion 76 on the side opposite to the shaft sh2. The spring 81 is compressed and arranged between a predetermined portion of the housing Hs and the engaging portion 76, and the engaging portion 76 is urged toward the release cam 78 side by a predetermined urging force. ..

Then, the fixing roller 44 and the release cam 78 are connected by the gear train Gt so that the lever 75 can be swung by driving the fixing motor M2 in the forward direction or the reverse direction.

The gear train Gt includes a drive gear gr1 as a first gear that is rotated in response to rotation from the fixing motor M2, a reversing gear gr2 as a second gear that reverses the rotation of the driving gear gr1, and a fixing roller 44. A fixing gear gr3 as a third gear that transmits the inverted rotation to the fixing roller 44 attached to one end, and a one-way gear gr4 as a fourth gear that transmits the rotation of the drive gear gr1 in only one direction. It also comprises a cam gear gr5 as a fifth gear that transmits the rotation of the one-way gear gr4 to the shaft sh3.

The one-way gear gr4 is idled as the fixing motor M2 is driven in the forward direction and the driving gear gr1 is rotated in the positive direction in response to the rotation of the fixing motor M2, and the rotation of the fixing motor M2 is rotated by the cam gear. The fixing motor M2 is driven in the opposite direction without being transmitted to the gr5, and the rotation of the fixing motor M2 is transmitted to the cam gear gr5 as the drive gear gr1 receives the rotation of the fixing motor M2 and is rotated in the opposite direction. ..

Further, the rotating plate 47 is attached to the pressure roller 45 and is rotated as the pressure roller 45 is rotated. Therefore, a shaft sh1 is rotatably arranged below the pressure roller 45 with respect to the frame Fr1 formed at a predetermined position of the housing Hs, and a transmission member made of an elastic body is provided at both ends of the shaft sh1. The rubber roller Rg is brought into pressure contact with the pressure roller 45. Therefore, the shaft sh1 is rotated along with the pressure roller 45 to be rotated, and the rotation of the pressure roller 45 is transmitted to the rotating plate 47 arranged outside the housing Hs.

Next, the operation of the release mechanism Mz will be described.

When the motor control unit Pr2 drives the fixing motor M2 in the forward direction, the rotation of the fixing motor M2 is transmitted to the fixing gear gr3 via the drive gear gr1 and the reversing gear gr2, and the fixing roller 44 rotates in the forward direction. Be done.

At this time, since the one-way gear gr4 is idled and the rotation of the fixing motor M2 is not transmitted to the cam gear gr5, the release cam 78 does not push the engaging portion 76, and the spring 81 pushes the engaging portion 76 by the urging force. Push in the direction of arrow A in FIG. As a result, the lever 75 is rotated about the axis sh2 in the direction of arrow B in FIG. 7, placed at the nip position, and the pressurizing roller 45 is pressed against the fixing roller 44 as shown in FIG. As a result, the fixing belt 46 (FIG. 3) is run, and the pressure roller 45 is rotated along with it.

Further, when the motor control unit Pr2 drives the fixing motor M2 in the opposite direction, the rotation of the fixing motor M2 is transmitted to the fixing gear gr3 via the drive gear gr1 and the reversing gear gr2, and the fixing roller 44 rotates in the opposite direction. Be done.

At this time, since the one-way gear gr4 transmits the rotation of the drive gear gr1 to the cam gear gr5, the release cam 78 is rotated in the direction of arrow C in FIG. 8, and the engaging portion 76 resists the urging force of the spring 81. And push it in the direction of arrow D in FIG. As a result, the lever 75 is rotated around the axis sh2 in the direction of arrow E in FIG. 8 and placed at the release position, and the pressurizing roller 45 is separated from the fixing roller 44 as shown in FIG. As a result, the fixing belt 46 cannot be run and the pressurizing roller 45 cannot be rotated.

In addition, the lever 75 is only formed with a predetermined gap between the lever 75 and the fixing roller 44 so that the lever 75 does not interfere with the fixing roller 44 when it is rotated about the shaft sh2. A hole ha of the size of is formed.

In the present embodiment, when the printer 10 (FIG. 2) is turned on or the fuser 16 is attached to and detached from the device main body Bd, the motor control unit Pr2 drives the fixing motor M2 in the opposite direction. , The release cam 78 pushes the engaging portion 76 in the direction of arrow D in FIG. As a result, the lever 75 is placed in the release position, and the pressurizing roller 45 is separated from the fixing roller 44 as shown in FIG. That is, the printer 10 is placed in a standby state in which the fixing belt 46 cannot be run and the pressurizing roller 45 cannot be rotated.

Next, the relationship between the rotating plate 47 and the reflection sensor 66 will be described.

FIG. 13 is a front view of the rotary plate and the reflection sensor according to the embodiment of the present invention, FIG. 14 is a side view of the rotary plate and the reflection sensor according to the embodiment of the present invention, and FIG. 15 is a lever in the embodiment of the present invention. A diagram showing the relationship between the rotating plate and the reflection sensor when the lever is placed in the release position, FIG. 16 shows the relationship between the rotating plate and the reflection sensor when the lever is placed in the nip position in the embodiment of the present invention. It is a figure which shows.

In the figure, 44 is a fixing roller, 45 is a pressure roller, 47 is a rotating plate, 66 is a reflection sensor, Sa is an irradiation surface, Ar1 is a first irradiation region, Ar2 is a second irradiation region, and q1 is a first. The white portion formed in the irradiation region Ar1 and q2 are the white portions formed in the second irradiation region Ar2, and q3 is the black portion formed in the second irradiation region Ar2.

In the present embodiment, since the rotating plate 47 is attached to the pressure roller 45, it is movably arranged with respect to the fixing roller 44, and moves with the movement of the pressure roller 45, so that the first and second plates 47 are moved. Take the operating position of.

Then, when the lever 75 is placed in the release position and the pressurizing roller 45 is separated from the fixing roller 44, the rotating plate 47 is placed in the first operating position and is reflected, as shown in FIG. The sensor 66 is opposed to the first irradiation region Ar1, the light emitting portion 72 (FIG. 5) of the reflection sensor 66 irradiates the first irradiation region Ar1 with light, and the light receiving portion 73 receives the reflected light of the white portion q1. To do.

Further, when the lever 75 is placed in the nip position and the pressurizing roller 45 is pressed against the fixing roller 44, the rotating plate 47 is placed in the second operating position, and as shown in FIG. 16, the reflection sensor. 66 is made to face the second irradiation region Ar2, the light emitting portion 72 of the reflection sensor 66 irradiates the second irradiation region Ar2 with light, and the light receiving portion 73 receives the reflected light of the white portion q2 or the black portion q3. ..

By the way, in the present embodiment, the rotation detection control unit Pr5 (FIG. 1) detects the rotation of the pressurizing roller 45 by the reflection sensor 66 while printing is being performed. If the detection accuracy of 66 is lowered, the rotation of the pressurizing roller 45 cannot be detected accurately.

Therefore, the rotation detection control unit Pr5 calibrates the reflection sensor 66, but after the power is turned on, the temperature of the fixing roller 44 becomes the fixing temperature, and the fixing motor M2 is driven to rotate. If the plate 47 waits until it is rotated, the rotation detection control unit Pr5 starts calibration later, and printing starts later by that amount.

Therefore, in the present embodiment, the calibration of the reflection sensor 66 is started before the fixing motor M2 is driven and the rotating plate 47 is rotated.

FIG. 17 is a first flowchart showing the operation of the printer according to the embodiment of the present invention, and FIG. 18 is a second flowchart showing the operation of the printer according to the embodiment of the present invention.

In the present embodiment, pre-calibration is performed as the first calibration and post-calibration is performed as the second calibration. In the pre-calibration, the light receiving of the reflection sensor 66 (FIG. 5) is received. The white level, which is the sensor output when the unit 73 receives the reflected light of the white portion q1 (FIG. 4), is adjusted, and in the post-calibration, the light receiving portion 73 of the reflection sensor 66 receives the reflected light of the black portion q3. The black level, which is the sensor output at that time, is adjusted.

First, the rotation detection control unit Pr5 (FIG. 1) waits for the conditions for calibration, that is, the calibration conditions to be satisfied.

Therefore, the rotation detection control unit Pr5 determines whether printing is being performed and whether the pressurizing roller 45 is separated from the fixing roller 44 in the fixing device 16 (FIG. 3), and printing is performed. It is determined that the calibration condition is satisfied when the pressurizing roller 45 is separated from the fixing roller 44. It should be noted that the calibration condition can be set so as to be satisfied when a predetermined time has elapsed since the previous calibration was performed.

For example, when the power of the printer 10 (FIG. 2) is turned on or the fixing device 16 is attached to and detached from the device main body Bd, the pressurizing roller 45 is separated from the fixing roller 44 as described above. , The calibration condition is satisfied.

When the calibration condition is satisfied, the rotation detection control unit Pr5 performs the precalibration process in a state where the pressurizing roller 45 is separated from the fixing roller 44 and the rotating plate 47 is stopped at the first operating position.

When the precalibration process is completed, the control unit 51 waits for the print request to be received from the host computer.

When the control unit 51 receives the print request from the host computer, the heating control unit Pr4 preheats the fuser 16 as the first warm-up. Therefore, the heating control unit Pr4 turns on the heater ht by the heater power supply 64, and controls the heater ht on and off so that the temperature of the fixing roller 44 detected by the thermistor s5 becomes the preset preheating temperature Ts. To do. The preheating temperature Ts is a temperature required to rotate the fixing roller 44 and the pressure roller 45, and is set lower than the fixing temperature Te required to fix the toner image on the paper P on the paper P. Toner.

When the temperature of the fixing roller 44 reaches the preheating temperature Ts in the preheating, the motor control unit Pr2 drives the fixing motor M2 in the positive direction by the fixing motor power supply 61. As a result, the fixing roller 44 is rotated in the forward direction, the lever 75 is placed at the nip position by the urging force of the spring 81 (FIG. 7), the pressure roller 45 is pressed against the fixing roller 44, and the fixing belt 46 runs. The pressure roller 45 is rotated. Further, the reflector 47 is rotated as the pressure roller 45 is rotated.

Subsequently, the heating control unit Pr4 starts post-heating of the fixing device 16 as a second warm-up, and controls the heater ht on and off so that the temperature of the fixing roller 44 becomes the fixing temperature Te.

Then, when the post heat is started and the rotation of the pressurizing roller 45 is started, the rotation detection control unit Pr5 presses the pressurizing roller 45 against the fixing roller 44, and the rotating plate 47 rotates at the second operating position. Perform post-calibration processing in the state where it is made.

When the post-calibration process is completed, the rotation detection control unit Pr5 starts detecting the rotation of the pressurizing roller 45 by the reflection sensor 66 based on the reflected light of the white portion q2 and the black portion q3 of the rotating plate 47.

Subsequently, when the post-heat is completed and the temperature of the fixing roller 44 reaches the fixing temperature Te, the motor control unit Pr2 drives the paper transfer motor M1 by the paper transfer motor power supply 57, and the print control unit Pr1 presses the pressurizing roller. While detecting the rotation of 45, the photoconductor drum 28 is exposed by the LED head 29, the image forming unit Q1 is operated by the image forming unit power supply 55, and the fixing device 16 is operated to perform printing.

Then, when printing is completed, the rotation detection control unit Pr5 finishes detecting the rotation of the pressurizing roller 45, and the motor control unit Pr2 drives the fixing motor M2 in the opposite direction by the fixing motor power supply 61. As a result, the lever 75 is placed in the release position, and the pressure roller 45 is separated from the fixing roller 44.

Next, the flowchart will be described.
Step S1 The rotation detection control unit Pr5 waits for the calibration condition to be satisfied. If the calibration condition is satisfied, the process proceeds to step S2.
Step S2 The rotation detection control unit Pr5 performs a pre-calibration process.
Step S3 The control unit 51 waits for the print request to be received from the host computer. When the print request is received from the host computer, the process proceeds to step S4.
Step S4 The heating control unit Pr4 preheats the fuser 16.
Step S5 The motor control unit Pr2 drives the fixing motor M2 in the forward direction.
Step S6 The heating control unit Pr4 starts the post-heating of the fuser 16.
Step S7 The rotation detection control unit Pr5 performs a post-calibration process.
Step S8 The rotation detection control unit Pr5 starts detecting the rotation of the pressurizing roller 45.
Step S9 The heating control unit Pr4 waits for the post heat to end. When the post heat is completed, the process proceeds to step S10.
Step S10 The motor control unit Pr2 prints.
Step S11 The rotation detection control unit Pr5 ends the detection of the rotation of the pressurizing roller 45.
Step S12 The motor control unit Pr2 drives the fixing motor M2 in the opposite direction to end the process.

Next, the pre-calibration process will be described.

FIG. 19 is a diagram showing a subroutine of precalibration processing according to the embodiment of the present invention.

First, the rotation detection control unit Pr5 (FIG. 1) sets the initial value of the light amount adjustment value in the light amount adjustment unit 71 (FIG. 5) of the reflection sensor 66.

Then, the reflection sensor 66 receives an instruction from the rotation detection control unit Pr5, irradiates the first irradiation region Ar1 with light by the light emitting unit 72, and receives the reflected light of the white portion q1 by the light receiving unit 73.

Subsequently, the rotation detection control unit Pr5 reads the white level generated by the light receiving unit 73 and determines whether or not the reflected light of the white portion q1 is saturated. Here, the saturation of the reflected light means that even if the light emitting unit 72 generates light having a light amount larger than the light amount adjusting value set in the light amount adjusting unit 71, the light receiving unit 73 receives the reflected light of the white portion q1. The state where the white level does not change.

When the reflected light of the white portion q1 is saturated, the rotation detection control unit Pr5 sets the light amount adjustment value set at this time as the specified value of the light amount adjustment unit 71, and records the white level in the RAM 53.

On the other hand, when the reflected light of the white portion q1 is not saturated, the rotation detection control unit Pr5 increases the light amount adjustment value until the reflected light of the white portion q1 is saturated.

Next, the flowchart will be described.
Step S2-1 The rotation detection control unit Pr5 sets the initial value of the light amount adjustment value.
Step S2-2 The reflection sensor 66 irradiates the first irradiation region Ar1 with light by the light emitting unit 72.
Step S2-3 The reflection sensor 66 receives the reflected light of the white portion q1 by the light receiving unit 73.
Step S2-4 The rotation detection control unit Pr5 determines whether or not the reflected light of the white portion q1 is saturated. If the reflected light of the white portion q1 is saturated, the process proceeds to step S2-5, and if the reflected light of the white portion q1 is not saturated, the process proceeds to step S2-6.
Step S2-5 The rotation detection control unit Pr5 records the white level in the RAM 53 and returns.
Step S2-6 The rotation detection control unit Pr5 increases the light amount adjustment value until the reflected light of the white portion q1 is saturated, and returns to step S2-3.

Next, the post-calibration process will be described.

FIG. 20 is a diagram showing a subroutine of post-calibration processing according to the embodiment of the present invention.

The reflection sensor 66 (FIG. 1) receives an instruction from the rotation detection control unit Pr5, irradiates the second irradiation region Ar2 with light by the light emitting unit 72 (FIG. 5), and the white portion q2 and the black portion q3 by the light receiving unit 73. Receives the reflected light of. Subsequently, the rotation detection control unit Pr5 determines the black level representing the sensor output of the reflected light of the black portion q3.

At this time, since the fixing motor M2 is driven in the positive direction and the rotating plate 47 is rotated, the light receiving unit 73 alternately receives the reflected light of the white portion q2 and the reflected light of the black portion q3 and rotates. The detection control unit Pr5 reads the white level and the black level alternately.

Generally, the sensor output of the light receiving unit 73 represents a voltage obtained by photoelectrically converting the amount of reflected light, so that the black level is lower than the white level. Therefore, the rotation detection control unit Pr5 determines the one having the lowest voltage among the white level and the black level read alternately as the black level.

Subsequently, the rotation detection control unit Pr5 reads out the white level recorded in the RAM 53 in the precalibration process, calculates the difference voltage δV which is the difference between the white level and the black level, and when the difference voltage δV is equal to or higher than the specified value Vs. Determine if there is.

When the difference voltage δV is equal to or higher than the specified value Vs, the rotation detection control unit Pr5 determines that the calibration can be performed normally, and ends the process.

After the calibration is performed in this way, the rotation detection control unit Pr5 subsequently detects the rotation of the pressurizing roller 45 based on the white level and the black level read from the light receiving unit 73.

On the other hand, when the difference voltage δV is less than the specified value Vs, the rotation detection control unit Pr5 displays a message indicating that the calibration could not be performed normally on the display unit of the operation panel 54, and a calibration error occurs. Is notified to the operator.

Then, the control unit 51 cancels each process of the print control unit Pr1, the motor control unit Pr2, the paper position detection unit Pr3, the heating control unit Pr4, the rotation detection control unit Pr5, and the like, and puts the printer 10 in the standby state.

Next, the flowchart will be described.
Step S7-1 The reflection sensor 66 irradiates the second irradiation region Ar2 with light by the light emitting unit 72.
Step S7-2 The reflection sensor 66 receives the reflected light of the white portion q2 and the black portion q3 by the light receiving unit 73.
Step S7-3 The rotation detection control unit Pr5 determines the black level.
Step S7-4 The rotation detection control unit Pr5 calculates the difference voltage δV.
Step S7-5 The rotation detection control unit Pr5 determines whether or not the difference voltage δV is equal to or greater than the specified value Vs. If the difference voltage δV is equal to or more than the specified value Vs, the process returns, and if the difference voltage δV is less than the specified value Vs, the process proceeds to step S7-6.
Step S7-6 The rotation detection control unit Pr5 notifies the operator of the calibration error and returns.

As described above, in the present embodiment, the rotation detection control unit Pr5 is in a state where the rotating plate 47 is placed in the first operating position before the rotation of the pressurizing roller 45 is started. After the calibration is performed and the rotation of the pressurizing roller 45 is started, the second calibration is performed with the rotating plate 47 placed in the second operating position, so that the calibration can be started earlier. You can start printing early.

Further, since the warm-up time can be shortened by the amount that the first calibration is performed before the warm-up is started, the power consumption at the time of warm-up can be reduced, and the cost of the printer 10 can be reduced. ..

In the present embodiment, the pressure roller 45 is supported by the lever 75, but the fixing roller 44 can also be supported by the lever 75. In that case, the rotating plate 47 is attached to the fixing roller 44.

Further, in the above-described embodiment, the printer 10 has been described, but the present invention can be applied to an image forming apparatus such as a copying machine, a facsimile, and a multifunction device.

The present invention is not limited to the above-described embodiment, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention.

10 Printer 44 Fixing roller 45 Pressurizing roller 47 Rotating plate 66 Reflection sensor M2 Fixing motor Pr4 Heating control unit Pr5 Rotation detection control unit

Claims (8)

(A) A rotating member that is rotated by driving the drive unit, and
(B) A member to be detected that is rotated as the rotating member rotates, and
(C) A detection member that is arranged to face the detected member and detects the detected member to generate a sensor output.
(D) It has a calibration processing unit that reads the sensor output of the detection member and calibrates the detection member.
(E) The member to be detected is movably arranged and takes the first and second operating positions.
(F) The calibration processing unit performs the first calibration based on the sensor output of the detection member in a state where the member to be detected is placed in the first operation position before the rotation of the rotating member is started. After the rotation of the rotating member is started, the second calibration is performed based on the sensor output of the detection member while the detected member is placed in the second operating position. Image forming device. The first calibration is performed based on the sensor output of the detection member in a state where the detected member is stopped, and the second calibration is performed in a state where the detected member is rotated. The image forming apparatus according to claim 1, wherein the image forming apparatus is performed based on the sensor output of the above. (A) The rotating member is a pressure roller disposed so as to be in contact with and detach from the fixing roller of the fixing device.
(B) The member to be detected is placed in the first operating position with the pressurizing roller separated from the fixing roller, and placed in the second operating position with the pressurizing roller pressed against the fixing roller. The image forming apparatus according to claim 1 or 2. The detection member is an optical sensor including a light emitting unit that generates light and irradiates the member to be detected, and a light receiving unit that receives the reflected light of the member to be detected and generates a sensor output. The image forming apparatus according to any one item. (A) The member to be detected includes an irradiation surface composed of first and second irradiation regions on a surface facing the optical sensor.
(B) The light emitting unit irradiates the first irradiation region with the generated light when the detected member is placed in the first operating position, and the detected member moves to the second operating position. The image forming apparatus according to claim 4, wherein when the image is placed, the generated light is irradiated to the second irradiation area. (A) In the first irradiation region, a first color portion is formed over the entire area in the circumferential direction.
(B) The image forming apparatus according to claim 5, wherein second and third color portions are alternately formed in the second irradiation region in the circumferential direction. (A) The first and second color portions are white portions.
(B) The image forming apparatus according to claim 6, wherein the third color portion is a black portion. (A) It has a warm-up processing unit that warms up by heating a predetermined member, and also has a warm-up processing unit.
(B) The image forming apparatus according to any one of claims 1 to 7, wherein the calibration processing unit performs the first calibration before the warm-up is started.

Images