JPH11327351A - Controller for fixing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a temperature irregularity from occurring in the surface temperature of a roller and to shorten the time required for warm-up by varying the rotating state of a driving part between in the midst of printing and during performing the warm-up. SOLUTION: This fixing unit 48 is provided with a heating roller 49 functioning as a 1st roller heating toner on a recording medium and a pressure roller 50 functioning as a 2nd roller disposed in contact with the roller 49. The rollers are supported so that they can be rotated by driving a fixing motor functioning as a driving part. In the unit 48, the rollers 49 and 50 are rotated in a direction (h) and in a direction (l), respectively, so that a toner image is fixed by both rollers. At the time, of warm-up, a fixing motor is driven in a reverse direction, and the rollers 49 and 50 in the unit 48 are rotated in the reverse direction until the warm-up is finished. Therefore, the irregular temperature is prevented from occurring in the surface temperature of the rollers 49 and 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device control device.

[0002]

2. Description of the Related Art Conventionally, in an image recording apparatus such as an electrophotographic printer, a fixing device is provided for fixing a toner image transferred to a recording medium. The fixing device includes a heating roller as a first roller having a heating heater therein, a pressure roller as a second roller disposed opposite to the heating roller, and an offset preventing liquid such as dimethyl silicone oil. , And an oil roller or the like disposed in contact with the heating roller.

In the fixing device, the surface temperature of the heating roller is controlled to a predetermined value. When the power of the image recording apparatus is turned on, the heater is energized,
Warm-up is performed.

[0004]

However, in the conventional fixing device, since the heating roller and the pressure roller are stopped during the warm-up, the surface temperature of the heating roller and the pressure roller is reduced. Temperature unevenness occurs. In particular, in the pressure roller, the part in contact with the heating roller is heated by the heating roller, while the other parts are not heated by the heating roller, so that the temperature unevenness of the surface temperature becomes extremely large, The time required for warm-up increases.

The present invention solves the above-mentioned problems of the conventional fixing device, suppresses the occurrence of temperature unevenness in the surface temperature of the first and second rollers, and reduces the time required for warm-up. It is an object of the present invention to provide a fixing device control device capable of shortening the fixing time.

[0006]

For this purpose, in a fixing device control device according to the present invention, a first roller provided with a heating element and a second roller provided in contact with the first roller are provided. Temperature control means for selectively energizing the heating element to control the surface temperature of the first roller, a driving unit for rotating the first and second rollers, and performing warm-up during printing. And a rotation state changing means for changing the rotation state of the drive unit during the operation.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a first diagram showing a color image recording device according to the first embodiment of the present invention, and FIG. 2 is a second diagram showing a color image recording device according to the first embodiment of the present invention. is there.

In the figure, in a color image recording apparatus 11, four sets of first to fourth printing mechanisms P1 to P4 are arranged in order from the insertion side of the recording medium 21 to the ejection side.
Each of the fourth printing mechanisms P1 to P4 is an electrophotographic L
It consists of an ED (light emitting diode) printing mechanism. The first printing mechanism P1 includes a photosensitive drum 1 according to a yellow image forming cartridge 12Y and yellow image data.
6 includes an LED head 13Y for exposing the surface of the recording medium 6, and a transfer roller 14Y for transferring a yellow toner image formed by the image forming cartridge 12Y to a sheet-like recording medium 21.

The second printing mechanism P2 is a LE for exposing the surface of the photosensitive drum 16 according to magenta image forming cartridge 12M and magenta image data.
D head 13M and image forming cartridge 12M
And a transfer roller 14M for transferring the magenta toner image formed on the recording medium 21. The third printing mechanism P3 includes a cyan image forming cartridge 12C, an LED head 13C that exposes the surface of the photosensitive drum 16 according to cyan image data, and a cyan toner formed by the image forming cartridge 12C. Transfer roller 1 for transferring an image to the recording medium 21
4C.

The fourth printing mechanism P4 includes a black image forming cartridge 12B, an LED head 13B for exposing the photosensitive drum 16 in accordance with black image data, and a black image forming cartridge 12B. The transfer roller 14B transfers a toner image to the recording medium 21. Since each of the image forming cartridges 12Y, 12M, 12C, and 12B has the same structure, only the structure of the yellow image forming cartridge 12Y will be described. The image forming cartridge 12 </ b> Y includes a photosensitive drum 16 that is rotated in the direction of an arrow a about a shaft 15, a charging roller 17 that uniformly and uniformly charges the surface of the photosensitive drum 16, and a developing unit 18. .

The developing section 18 includes a developing roller 19a, a developing blade 19b, a sponge roller 19c, a toner tank 19d, and a stirring member 19e. Each of the image forming cartridges 12Y, 12M, 12C,
Each element of 12B is supported by each cartridge frame 24. In the developing section 18, the toner tank 1
The non-magnetic one-component toner (not shown) supplied from 9d is agitated by an agitating member 19e and sent to a developing roller 19a via the sponge roller 19c, and a thin layer is formed on the surface of the developing roller 19a by a developing blade 19b. And the photosensitive drum 16 and the developing roller 19a
Is sent to the contact surface. When the toner is thinned, the developing roller 19a and the developing blade 1
9b is strongly rubbed (rubbed) and charged. In the present embodiment, the toner is charged to a negative polarity. In the present embodiment, the developing roller 19a is made of a semiconductive rubber material. The toner tank 19d is replaced when the toner runs out.

Next, the LED heads 13Y, 13M,
13C and 13B will be described. The LED head 13
Y, 13M, 13C and 13B are LED arrays (not shown) and a drive I (not shown) for driving the LED arrays.
C, a substrate (not shown) on which the drive IC is mounted;
An LED is formed according to a color image signal transmitted from a higher-level device via an interface unit (not shown).
Each LED element of the array is selectively caused to emit light to form an electrostatic latent image on the surface of the photosensitive drum 16. Then, the toner on the developing roller 19a is made to adhere to the electrostatic latent image by electrostatic force, and a toner image is formed.

Each of the LED heads 13Y, 13M, 1
3C and 13B are supported by the holding member 96, and are pressed downward in the drawing by the urging force of the spring 17a.
Further, the urging force of the spring 17b fixed to the holding member 96 causes the cartridge frame 24 to be pressed downward at two places on the left and right (front and back in the figure). Therefore, the image forming cartridges 12Y, 12M, 12C, and 12B can be reliably held and positioned by the pressing forces of the springs 17a and 17b. Further, each image forming cartridge 1 in the transport direction of the recording medium 21 is
2Y, 12M, 12C, and 12B, a spring 17c is disposed downstream of the guide frame 90.
Is held by the spring support portion 90d. The spring 17
The urging force of c is made smaller than the urging forces of the springs 17a and 17b.

A transfer portion between each photosensitive drum 16 and each transfer roller 14Y, 14M, 14C, 14B includes:
An endless transport belt 20 is provided so as to run freely.
The developing unit 18 of the image forming cartridge 12Y
Contains yellow toner in the image forming cartridge 12M.
Magenta toner, the cyan toner in the developing unit 18 of the image forming cartridge 12C, and the black toner in the developing unit 18 of the image forming cartridge 12B.

The yellow image data generated by the color image signal is generated by the LED head 13Y of the first printing mechanism P1, and the color image signal is generated by the LED head 13M of the second printing mechanism P2. Magenta image data, cyan image data generated by the color image signal on the LED head 13C of the third printing mechanism P3, and color image signal on the LED head 13B of the fourth printing mechanism P4. The input black image data is input.

By the way, the image forming cartridges 12Y,
12M, 12C, and 12B, the conveyor belt unit 2
0A is provided. The transport belt unit 20A includes a transport belt 20, a driving roller 31, and driven rollers 32a to 32a.
2c, cleaning blade 34, transfer roller 14
Y, 14M, 14C, 14B, a static elimination brush 99, and a frame 84 that supports these components. A guide portion 93 for guiding the recording medium 21 to the fixing device 48 and guide grooves 84a and 84b are formed in a part of the frame body 84, and are fixed to the main body side in the guide grooves 84a and 84b. The frame 84 is positioned by inserting the guides 85a and 85b of the frame 85.

Next, the transport belt unit 20A will be described. The transport belt 20 is made of a high-resistance semiconductive plastic film, is formed into a seamless endless shape, and includes a driving roller 31, a driven roller 32a to
32c and transfer rollers 14Y, 14M, 14C, 14B
It is stretched between. Note that the resistance value of the transport belt 20 is such that when the recording medium 21 is attracted to the transport belt 20 by electrostatic force and the recording medium 21 is separated from the transport belt 20, the static electricity remaining on the transport belt 20 is natural. Is set in such a range as to be neutralized.

The drive roller 31 is connected to a belt running motor (not shown), and is rotated by the belt running motor in the direction of arrow c. The driven roller 32b is urged in the direction of arrow g by a spring (not shown), and the tension is always applied to the transport belt 20 by the urging force of the spring. The transport belt unit 20
When A is mounted on the main body of the image recording apparatus 11, the upper half portion 20a of the transport belt 20 is connected to the first to fourth printing mechanisms P1.
To P4, the photosensitive drum 16 and the transfer rollers 14Y, 14M, 14C, 14B are brought into contact with each other with the upper half 20a interposed therebetween.
The driven roller 32a and the tip of the cleaning blade 34 are brought into contact with each other with the lower half 20b of the transport belt 20 interposed therebetween.

The cleaning blade 34 is made of a flexible rubber or plastic material, scrapes off the toner remaining on the surface of the conveyor belt 20, and removes the toner from a waste toner tank surrounded by a frame 84. Drop into part 35. Therefore, while the transport belt 20 is running in the direction of the arrow f, the transport belt 20 is always cleaned.

Further, the suction roller 47 is connected to the transport belt 20.
The recording medium 21, which is pressed against the driven roller 32 c via the sheet feeding mechanism 36 and conveyed by the sheet feeding mechanism 36, is charged, and the recording medium 21 is attracted to the conveyance belt 20 by electrostatic force.
For this purpose, the suction roller 47 is made of a semiconductive rubber material having a large resistance value. Then, a charge removing brush 99 is provided so as to face the drive roller 31 via the transport belt 20. The neutralization brush 99 neutralizes the recording medium 21 that has been adsorbed and conveyed by the transport belt 20, and facilitates separation from the transport belt 20.

A paper feed mechanism 36 is provided at the lower right of the image recording apparatus 11 in FIG.
The paper storage cassette comprises a recording medium storage box 37, a push-up plate 38, and a pressing means 39. The hopping mechanism includes a discriminating means 40, a spring 41, and a paper feed roller 42.

In this case, the recording medium 21 accommodated in the recording medium accommodation box 37 is pushed by the pushing means 39 by the pushing means 39.
8, the sheet is pressed against the sheet feeding roller 42, and is discriminated one by one by the discriminating means 40 pressed against the sheet feeding roller 42 by the spring 41. In this state, when the paper feed roller 42 is rotated in the direction of arrow h by a motor (not shown),
The recording medium 21 sandwiched between the paper feed roller 42 and the discriminating means 40 is guided by sheet guides 43 and 44 and sent to registration rollers 70 and 71. The registration rollers 70 and 71 determine the timing between the front end of the recording medium 21 and the image formation by the image forming cartridges 12Y, 12M, 12C and 12B. Reference numeral 72 denotes a registration roller 7 in the conveyance direction of the recording medium 21.
The photosensor is disposed upstream of 0 and 71 and detects the front end and the rear end of the recording medium 21.

Subsequently, when the registration rollers 70 and 71 are rotated in the direction of the arrow by a motor (not shown), the recording medium 21 is guided by a medium guide 46,
It is sent between the suction roller 47 and the transport belt 20. The front cover 104 is supported on the main body so as to be rotatable around a fixed shaft 104a.
04b by opening the front cover 1
A lock portion (not shown) of the main body 04 is disengaged from the engagement portion of the main body, and the registration roller 71, the suction roller 47, and the sheet guide 4
4 come off the main body together. The shafts extending to both ends of the registration roller 71 and the suction roller 47 are rotatably supported by guide shafts 106 and 107. The guide shafts 106 and 107 are provided with springs 106a and 107 provided in grooves of the front cover 104.
It is urged downward by a. Therefore, when the front cover 104 is closed, the spring 106
The registration roller 71 is pressed against the registration roller 70 and the suction roller 47 is pressed against the driven roller 32c by the urging forces a and 107a. When a high voltage is applied to the suction roller 47 in a state where the driven roller 32c is grounded and the front cover 104 is closed, the recording medium 21 is attracted to the conveyance belt 20 by a potential difference. I have.

Further, a fixing device 48 is provided downstream of the fourth printing mechanism P4 in the transport direction of the recording medium 21. The fixing device 48 fixes the toner image transferred by the transfer belt 20 and transferred to the recording medium 21, and includes a heating roller 49 as a first roller for heating the toner on the recording medium 21, and There is a pressure roller 50 as a second roller disposed in contact with the heating roller 49 by the urging force of a spring that does not. The heating roller 49 and the pressure roller 50 are driven by a fixing motor as a driving unit (not shown) so that the heating roller 49 is moved in the directions of arrows h and l, and the pressure roller 50 is moved in the directions of arrows i and m. It is supported so that it can be rotated.

The heating roller 49 is formed by covering a hollow cylindrical mandrel made of aluminum or the like with a heat-resistant elastic layer such as a silicone rubber-based material, and a Teflon (trade name) -based PFA on the heat-resistant elastic layer. , ETTE or the like. A heater 1 as a heating element such as a halogen lamp is provided in a mandrel of the heating roller 49.
01 is provided. The pressure roller 50 is formed by coating a heat-resistant inelastic layer made of heat-resistant plastic on a mandrel made of aluminum, stainless steel, or the like, and forming a Teflon-based PFA, ETTE, or the like on the heat-resistant inelastic layer. It is formed by coating a release layer. As described above, by forming the heat-resistant elastic layer on the heating roller 49 and the heat-resistant inelastic layer on the pressure roller 50, a pressure contact portion (nip portion) is formed between the heating roller 49 and the pressure roller 50. You.

The outer peripheral surface of the heating roller 49 has a first surface for detecting the surface temperature of the heating roller 49.
A thermistor 102 serving as a temperature detecting means is disposed in contact with the heater, and a temperature control means of a control circuit (not shown) selectively energizes the heater 101 based on the surface temperature of the heating roller 49 detected by the thermistor 102. Then, the surface temperature of the heating roller 49 is controlled and maintained at a predetermined value. On the other hand, a thermistor 103 as a second temperature detecting means for detecting the surface temperature of the pressing roller 50 is provided in contact with the outer peripheral surface of the pressing roller 50, and the temperature control means The temperature of the heater 101 is controlled based on the surface temperature of the pressure roller 50 detected by the thermistor 103, and the surface temperature of the pressure roller 50 is maintained at a predetermined value.

An oil roller 1 as a coating means
16 is disposed on the outer peripheral surface of the heating roller 49 and is supported by the support member 105 so as to be rotatable in the directions of arrows j and n. The oil roller 116 is impregnated with an anti-offset liquid such as dimethyl silicone oil, and the anti-offset liquid is applied to the heating roller 49 as the heating roller 49 rotates. Therefore, it is possible to suppress the toner from causing the offset phenomenon. Further, a cleaning roller 117 as a cleaning unit is disposed upstream of the oil roller 116 and downstream of the pressure roller 50 in the rotation direction when the heating roller 49 is rotated in the direction of arrow h. You. The cleaning roller 117 is rotatably supported by the support member 105 in the directions of arrows k and p. The cleaning roller 117 is formed of a material having good oil absorbency and good toner adhesion, and removes toner, oil, paper dust, and the like remaining on the outer peripheral surface of the heating roller 49. In this embodiment, the oil roller 116 is used as a coating means.
However, an oil pad may be used instead of the oil roller 116, or a roll-up web may be used.

Further, on the downstream side of the fixing device 48 in the transport direction of the recording medium 21, the recording medium 21 is
A plurality of separation claws 118 are provided for separation from the hook 9. The separation claw 118 is arranged in the longitudinal direction of the heating roller 49,
The tip is disposed so as to contact the outer peripheral surface of the heating roller 49. The upper case 1 is located above the fixing device 48.
The upper case 119 supports the heating roller 49, the thermistor 102, and the support member 105. The support member 105 is detachably provided to the upper case 119. A lower case 120 is disposed below the fixing device 48, and the lower case 1
Reference numeral 20 denotes a guide 120a for supporting the pressure roller 50 and guiding the recording medium 21.

A pair of transport rollers 121 is located downstream of the separation claw 118 in the transport direction of the recording medium 21.
The transport roller 121 sends the recording medium 21 discharged from the fixing device 48 to discharge rollers 126 and 127 via guides 122 to 125. The discharge roller 12
6 and 127, the recording medium 21 sent to the upper cover 1
28 are discharged to the discharge stacker unit 128a. The photo sensor 109 detects the rear end of the recording medium 21. Further, the transport roller 121 and the discharge rollers 126, 12
7 constitutes a recording medium conveying means.

The upper cover 128 is fixed to the fixed shaft 1.
A switch (not shown), which is opened and closed by being rotated about the center 28b and is linked to opening and closing of the upper cover 128, is provided in the main body. The switch is turned off when the upper cover 128 is opened, and the upper cover 1 is turned off.
Turns on when 28 is closed. Then, the LED heads 13Y, 13M, 13C,
The 13B holding member 96, guides 124 and 125, and discharge rollers 126 and 127 are supported. When the upper cover 128 is opened, each image forming cartridge 12
The Y, 12M, 12C, and 12B move upward by the urging force of the spring 17c, and each image forming cartridge 12Y,
The photoconductor drums 16 of 12M, 12C, and 12B move away from the transport belt 20.

The charging roller 17, developing roller 19a, sponge roller 19c, transfer rollers 14Y, 14M, 14C, 1
A high-voltage power supply 150 for applying a high voltage to the 4B and the suction roller 47 is provided. Immediately below the fixing device 48, a circuit control unit 151 and a low-voltage power supply 152 for applying a low-voltage to the circuit control unit 151 are provided. Will be arranged.

Next, a control circuit of the image recording apparatus 11 will be described. FIG. 3 is a block diagram of a color image recording apparatus according to the first embodiment of the present invention. In addition,
In the drawing, reference numerals Y, M, C, and B denote yellow, magenta, cyan, and black image forming cartridges 12 respectively.
Y (FIG. 2), 12M, 12C, and 12B (FIG. 1).

In the figure, 51 is a working register,
The control circuit 51 is a control circuit including a microprocessor having a timer, a ROM, and the like. The control circuit 51 controls the image recording apparatus 11. The control circuit 51 includes each sponge roller 19 of each developing unit 18 of the first to fourth printing mechanisms P1 to P4.
c, a DB bias power supply 53 for applying a voltage to each developing roller 19a of each developing unit 18, a first to fourth printing mechanism P
A charging power supply 54 for applying a voltage to each of the charging rollers 17 of the first to P4, and first to fourth printing mechanisms P1 to P4
Transfer power supplies 55Y, 55M, and 55 that apply voltages to the transfer rollers 14Y, 14M, 14C, and 14B, respectively.
C and 55B are respectively connected.

The control circuit 51 is connected to a power supply 56 for suction / charging. The power supply 56 for suction / charging applies a charging voltage to the suction roller 47, and the driven roller 32c is grounded to a ground (not shown). Is done. Therefore, an electrostatic force is generated by the potential difference between the driven roller 32c and the suction roller 47, and the recording medium 21 is sucked to the transport belt 20 by the electrostatic force. The photosensitive drum 16 is grounded via a connection wiring member (not shown).

The SP bias power supply 52 and each DB
Bias power supply 53, charging power supply 54, transfer power supply 5
5Y, 55M, 55C, 55B and power supply 56 for adsorption charging
Are turned on / off by an instruction from the control circuit 51, and constitute a high-voltage power supply 150. Further, the control circuit 51 includes print control circuits 58Y, 58M, 58 corresponding to the first to fourth printing mechanisms P1 to P4, respectively.
C and 58B are connected. The respective print control circuits 5
8Y, 58M, 58C, and 58B store the memories 59Y,
9M, 59C, and 59B, respectively, receives yellow image data, magenta image data, cyan image data, and black image data, and in accordance with instructions from the control circuit 51, receives the LED heads 13Y, 13M, 13C, and 1C.
3B, the exposure time of each LED element of the LED array (not shown) is controlled, and an electrostatic latent image is formed on the surface of each photoconductor drum 16.

For this purpose, when the interface unit 60 receives a color image signal transmitted from a higher-level device (not shown), for example, a host computer, the interface unit 60 separates the color image signal into colors and converts the color image signal into yellow image data and magenta image data. Data, cyan image data, and black image data. The yellow image data is stored in the memory 59Y, and the magenta image data is stored in the memory 59M.
Then, the cyan image data is stored in the memory 59C, and the black image data is stored in the memory 59B.

The control circuit 51 includes a fixing device driver 61 as a temperature control unit, a motor drive circuit 62 as a drive unit control unit, and a sensor receiver driver 6.
6 is connected. The fixing device driver 61 energizes or stops energizing the heater 101 in the heating roller 49 so that the surface temperature of the heating roller 49 detected by the thermistor 102 is maintained at a predetermined value.

Then, the motor drive circuit 62
3 to rotate the paper feed roller 42 and drive the motor 64 to drive the transfer rollers 14Y, 14M, 1M of the first to fourth printing mechanisms P1 to P4.
4C, 14B, each photosensitive drum 16, each charging roller 1
7, each developing roller 19a and each sponge roller 19c,
Then, the driving roller 31, the registration rollers 70 and 71, and the suction roller 47 are rotated. Further, the motor drive circuit 62 drives the fixing motor 65 to
Heating roller 49, pressure roller 50, discharge roller 126,
127, the fixing motor 65 is driven in the reverse direction by rotating the pair of transport rollers 121 and operating a rotation direction switching unit (not shown), thereby switching the rotation direction of the heating roller 49 and the pressing roller 50.

The motors 63 and 64 and the fixing device motor 6
Each element rotated by driving 5 is connected by a gear or a belt (not shown). And
The sensor receiver driver 66 includes each photo sensor 72,
The controller 109 operates to send the output waveforms of the photosensors 72 and 109 to the control circuit 51 as detection signals. Also, 1
Reference numeral 52 denotes a low-voltage power supply. The low-voltage power supply 152 includes a control circuit 51, print control circuits 58Y, 58M, 58C, 58B,
Memory 59Y, 59M, 59C, 59B and high voltage power supply 1
A low voltage of DC (direct current) is applied to 50. When a voltage is applied from the low-voltage power supply 152 to the high-voltage power supply 150,
The low voltage is converted into a high voltage by a transformer (not shown) or the like. The low-voltage power supply 152 and the high-voltage power supply 1
A switch 88 is provided between the switch 50 and the switch 50. The switch 88 turns off when the upper cover 128 is opened, and turns on when the upper cover 128 is closed. Therefore, the upper cover 12
8, the application of the voltage to the high voltage power supply 150 is stopped, so that the charging roller 17, the developing roller 19a, the sponge roller 19c, and the transfer rollers 14Y, 14M, 1
The application of the high voltage to 4C and 14B is forcibly stopped. In addition, 89 is an AC power switch of the main body,
The AC power switch 89 is turned on / off to selectively supply, for example, 100 [V] commercial power (AC).

Next, the operation of the image recording apparatus 11 having the above configuration will be described. First, when the AC power supply switch 89 is turned on, the low-voltage power supply 152 is started, and the low-voltage voltage is applied to the control circuit 51, the print control circuits 58Y, 58M, and 58.
C, 58B, memories 59Y, 59M, 59C, 59B and high voltage power supply 150. Subsequently, the control circuit 51 performs a predetermined initial setting and then drives the fixing device driver 61 to perform warm-up until the surface temperature of the heating roller 49 reaches a predetermined value. After the completion of the warm-up, the control circuit 51 always keeps the surface temperature of the heating roller 49 at a constant value.

When the initialization of the image recording apparatus 11 is completed in this way, the control circuit 51
And waits for a color image signal to be transmitted from the host computer via the host computer. And the control circuit 51
Receives the color image signal, generates the yellow image data, magenta image data, cyan image data, and black image data by separating the color image signal for each color, and stores the yellow image data in a memory. 59
The image data of Y is stored in the memory 59M, the image data of cyan is stored in the memory 59C, and the image data of black is stored in the memory 59B.

Subsequently, when the reception of the color image signal is completed, the control circuit 51 drives the fixing device driver 61 again to energize the heating heater 101 and raise the surface temperature of the heating roller 49 to a predetermined value. . Next, the control circuit 51
Drives a motor 63 via a motor drive circuit 62,
The paper feed roller 42 is rotated. By the rotation of the paper feed roller 42, only one recording medium 21 in the recording medium storage box 37 is fed out to the sheet guides 43 and 44, and the control circuit 51
When the front end of the recording medium 21 is detected by the photo sensor 72 via the sensor receiver driver 66, the motor 63 is driven to convey the recording medium 21 by a predetermined amount from the detection position. The front end of the recording medium 21 is
When the control circuit 51 reaches 0, 71, the control circuit 51
3 is further conveyed slightly by the recording medium 21. As a result, the recording medium 21 has its front end
By pressing between the rollers 0 and 71, a slight loop is formed, and the skew of the recording medium 21 is corrected by the loop.

Next, the control circuit 51 controls the motor drive circuit 6
2 to drive the transfer rollers 14Y, 14M, 14C, 14 of the first to fourth printing mechanisms P1 to P4.
B, each photosensitive drum 16, each charging roller 17, each developing roller 19a, each sponge roller 19c, the driving roller 3
1. While rotating the registration rollers 70 and 71 and the suction roller 47, respectively, and turning on the suction charging power supply 56, a voltage is applied to the suction roller 47. At the same time, the control circuit 51 drives the fixing motor 65 via the motor drive circuit 62 to rotate the discharge rollers 126 and 127 and the pair of transport rollers 121, and presses the heating roller 49 in the direction of arrow h. The roller 50 is rotated in the direction of arrow i, the oil roller 116 is rotated in the direction of arrow j, and the cleaning roller 117 is rotated in the direction of arrow k (rotation in the forward direction).

The registration rollers 70 and 71 are rotated in the direction of the arrow, and the recording medium 21 is conveyed while being guided by the medium guide 46 by the registration rollers 70 and 71. When the front end of the recording medium 21 reaches between the suction roller 47 and the transport belt 20, the recording medium 2
The front end of 1 is attracted to the conveyor belt 20 by the electrostatic force between the attracting roller 47 and the driven roller 32c. In addition,
When the rear end of the recording medium 21 moves away from the discriminating means 40, the control circuit 51 stops the motor 63 via the motor drive circuit 62.

When the front end of the recording medium 21 has passed the suction roller 47, the control circuit 51 turns on the charging power source 54, the DB bias power source 53, and the SP bias power source 52, respectively, Roller 1
A voltage is supplied to 9a and the sponge roller 19c. As a result, the surface of the photosensitive drum 16 is
7 to be uniformly and uniformly charged,
A predetermined high voltage is applied to the sponge roller 19c and the developing roller 19a.

Next, the control circuit 51 issues a command to the memory 59Y, reads out one line of yellow image data from the memory 59Y, and sends it to the print control circuit 58Y. The print control circuit 58Y changes the yellow image data sent from the memory 59Y into a form that can be sent to the LED head 13Y and sends it to the LED head 13Y according to a command from the control circuit 51. The LED head 13
Y is L corresponding to the sent yellow image data.
The LED elements of the ED array emit light, and the photosensitive drum 16
To form an electrostatic latent image for one line on the surface of. In this manner, the photosensitive drums 16 are successively arranged according to the yellow image data sent from the memory 59Y line by line.
Exposure is completed when an electrostatic latent image is formed on the surface of the substrate and an electrostatic latent image is formed in accordance with the yellow image data corresponding to the length in the sub-scanning direction.

Subsequently, a developing roller 19a is applied to the electrostatic latent image.
As a result, the yellow toner is adhered, and a yellow toner image is formed. Then, when the front end of the recording medium 21 reaches the transfer portion between the photosensitive drum 16 and the transfer roller 14Y, the control circuit 51 turns on the transfer power supply 55Y. As a result, the yellow toner image on the photosensitive drum 16 is electrically transferred to the recording medium 21 by the transfer roller 14Y. That is, the photosensitive drum 1
As the roller 6 is rotated, one page of the yellow toner image is sequentially transferred to the recording medium 21.

Subsequently, when the rear end of the recording medium 21 reaches the transfer section, the control circuit 51 issues a transfer power supply 55Y.
Turn off. The transport belt 20 is continuously run, and the recording medium 21 is sent from the image forming cartridge 12Y to the image forming cartridge 12M, and the magenta toner image is transferred to the recording medium 21 by the image forming cartridge 12M.

To this end, the control circuit 51 includes a memory 59
A command is issued to M, and one line of magenta image data is read from the memory 59M and sent to the print control circuit 58M. The print control circuit 58M changes the magenta image data sent from the memory 59M into a form that can be sent to the LED head 13M and sends it to the LED head 13M according to a command from the control circuit 51. The LED head 13M causes the LED elements of the LED array corresponding to the sent magenta image data to emit light, and forms a one-line electrostatic latent image on the surface of the photosensitive drum 16. In this manner, the electrostatic latent images are formed one after another on the surface of the photosensitive drum 16 according to the magenta image data sent from the memory 59M for each line, and the magenta image corresponding to the length in the sub-scanning direction is formed. The exposure ends when an electrostatic latent image is formed according to the data.

Subsequently, a developing roller 19a is applied to the electrostatic latent image.
As a result, the magenta toner is adhered to form a magenta toner image. Then, when the front end of the recording medium 21 reaches the transfer portion between the photosensitive drum 16 and the transfer roller 14M, the control circuit 51 turns on the transfer power supply 55M. As a result, the magenta toner image on the photosensitive drum 16 is electrically transferred to the recording medium 21 by the transfer roller 14M. That is, the photosensitive drum 1
As the roller 6 is rotated, a magenta toner image of one page is sequentially transferred onto the recording medium 21 in a superimposed manner.

Subsequently, when the rear end of the recording medium 21 reaches the transfer section, the control circuit 51 turns off the transfer power supply 55M. Then, the recording medium 21 further stores the image forming cartridge 12C from the image forming cartridge 12M.
The cyan toner image is transferred to the recording medium 21 by the image forming cartridge 12C.

For this purpose, the control circuit 51 includes a memory 59
A command is issued to C, and one line of cyan image data is read from the memory 59C and sent to the print control circuit 58C.
The print control circuit 58C changes the cyan image data sent from the memory 59C into a form that can be sent to the LED head 13C and sends it to the LED head 13C according to a command from the control circuit 51. The LED head 13
C is the LE corresponding to the transmitted cyan image data.
The LED elements of the D array emit light to form an electrostatic latent image for one line on the surface of the photosensitive drum 16. In this manner, an electrostatic latent image is formed on the surface of the photosensitive drum 16 one after another according to the cyan image data sent from the memory 59C for each line, and the cyan image corresponding to the length in the sub-scanning direction is formed. The exposure ends when an electrostatic latent image is formed according to the data.

Subsequently, a developing roller 19a is applied to the electrostatic latent image.
Causes the cyan toner to adhere, thereby forming a cyan toner image. Then, when the front end of the recording medium 21 reaches the transfer portion between the photosensitive drum 16 and the transfer roller 14C, the control circuit 51 turns on the transfer power supply 55C. As a result, the cyan toner image on the photosensitive drum 16 is electrically transferred to the recording medium 2 by the transfer roller 14C.
Transferred to 1. That is, as the photosensitive drum 16 is rotated, one page of the cyan toner image is sequentially transferred onto the recording medium 21 in a superimposed manner.

Subsequently, when the rear end of the recording medium 21 reaches the transfer section, the control circuit 51 turns off the transfer power supply 55C. Then, the recording medium 21 further moves from the image forming cartridge 12C to the image forming cartridge 12B.
The black toner image is transferred to the recording medium 21 by the image forming cartridge 12B. For this purpose, the control circuit 51 issues a command to the memory 59B, reads out one line of black image data from the memory 59B, and sends it to the print control circuit 58B. The print control circuit 58
B is stored in the memory 59B according to a command from the control circuit 51.
Is transmitted to the LED head 13B in a form that can be transmitted to the LED head 13B. The LED head 13B is provided with an LED array LE corresponding to the transmitted black image data.
The D element emits light to form an electrostatic latent image for one line on the surface of the photosensitive drum 16. In this manner, the electrostatic latent images are sequentially formed on the surface of the photosensitive drum 16 in accordance with the black image data sent from the memory 59B for each line, and the black image corresponding to the length in the sub-scanning direction is formed. The exposure ends when an electrostatic latent image is formed according to the data.

Subsequently, the developing roller 19a is applied to the electrostatic latent image.
As a result, black toner is adhered to form a black toner image. Then, when the front end of the recording medium 21 reaches the transfer portion between the photosensitive drum 16 and the transfer roller 14B, the control circuit 51 turns on the transfer power supply 55B. As a result, the black toner image on the photosensitive drum 16 is electrically transferred to the recording medium 21 by the transfer roller 14B. That is, the photosensitive drum 1
As the roller 6 is rotated, the black toner image for one page is sequentially transferred onto the recording medium 21 in a superimposed manner.

Subsequently, when the rear end of the recording medium 21 reaches the transfer section, the control circuit 51 turns off the transfer power supply 55B. As described above, the toner image of each color is recorded on the recording medium 2.
1 and transferred to form a color toner image. Then, the recording medium 21 is sent to the charge removing brush 99 by the transport belt 20, and the charge is removed by the charge removing brush 99.
As a result, the recording medium 21 is separated from the conveyance belt 20 above the driving roller 31, guided by the guide unit 93, and sent to the fixing device 48.

In the fixing device 48, the heating roller 49 is rotated in the direction of arrow h, and the pressure roller 50 is rotated in the direction of arrow i.
The color toner image is fixed on the recording medium 21 by
A color image is formed on the recording medium 21. And
When the fixing by the fixing device 48 is completed, the recording medium 21 is transported by the transport roller 121 and the guides 122 to 12 are transported.
5 and is sent to discharge rollers 126 and 127. After that, the recording medium 21 is discharged by the discharge rollers 126, 1
27, the sheet is discharged to the discharge stacker 128a. Note that the control circuit 51 determines that the photo sensor 109 is the recording medium 2.
By detecting the trailing edge of No. 1, it is known that the recording medium 21 has been discharged.

When the ejection of the recording medium 21 is completed in this manner, the control circuit 51 sets the SP bias power supply 52 and the DB
The bias power supply 53 and the charging power supply 54 are turned off, and the motor 64 is stopped via the motor drive circuit 62. Reference numeral 103 denotes a thermistor. By the way, the image recording apparatus 11 is in a state of waiting for a printing operation to be performed,
That is, the printer is placed in a standby state and a state where the printing operation is started, that is, a printing operation state.

Next, a description will be given of a temperature control process of the fixing unit 48 when the warm-up is performed. FIG. 4 is a flowchart showing the operation of the fixing device according to the first embodiment of the present invention. In this case, when the warm-up is started, the fixing motor 65 (FIG. 3) is driven in the reverse direction, and the heating roller 49 and the pressure roller 50 of the fixing device 48 (FIG. 1) are reversed until the warm-up is completed. Rotated in the direction. Therefore, the surface temperature T _r of the heating roller 49 and the pressure roller 50, a temperature irregularity in T _p can be suppressed.

The surface temperature _Tr is maintained at 165 ° C., and the surface temperature T _p is maintained at 100 ° C. Therefore, since the surface temperature _Tr does not decrease, the occurrence of the offset phenomenon can be prevented, and the toner on the recording medium 21 does not adhere to the surface of the heating roller 49. Further, the glossiness of the color image formed on the recording medium 21 is not lost.

[0061] Then, when the OHP sheet is used as a recording medium 21, since the surface temperature T _p can be maintained at 100 [℃], it is possible to increase the transmittance of the OHP sheet. Moreover, in order that the surface temperature T _r, the first for maintaining T _p, it is not necessary to exceptionally increase the second predetermined temperature, it is possible to reduce the power consumption of the heater 101.

During the warm-up, the fixing motor 65 is driven in the reverse direction, the heating roller 49 is moved in the direction of the arrow 1 and the pressure roller 50 is moved in the direction of the arrow m.
16 is rotated in the direction of the arrow n, and the cleaning roller 117 is rotated in the direction of the arrow p, so that the anti-offset liquid that oozes out of the oil roller 116 and adheres to the heating roller 49 is removed. It can be immediately sucked and removed by the cleaning roller 117. Therefore, it is possible to prevent the excessive offset prevention liquid from adhering to the surface of the pressure roller 50, so that the back surface of the recording medium 21 is not stained by the offset prevention liquid.

Moreover, the heating roller 49 and the pressure roller 5
The heat transfer to 0, since the surface temperature T _p can be maintained at 100 [℃], it is not necessary to provide a heater inside the pressure roller 50. Therefore, not only can the power consumption be reduced, but also the cost of the image recording device 11 can be reduced. Next, the flowchart will be described. Step S1 The AC power switch 89 is turned on, the low-voltage power supply 152 is started, and the low-voltage is controlled by the control circuit 51,
It is applied to the print control circuits 58Y, 58M, 58C, 58B, the memories 59Y, 59M, 59C, 59B and the high voltage power supply 150, respectively. Then, the control circuit 51 executes a predetermined initial setting. Step S2: Whether the photo sensor 109 has detected the rear end of the recording medium 21, that is, whether the guides 122 to
It is determined whether or not the recording medium 21 has passed through the paper discharge section between the five. If the recording medium 21 has passed, go to step S4.
If not, the process proceeds to step S3. Step S3: The control circuit 51 determines that a jam has occurred, displays on a display means (not shown) that the jam has occurred, and performs jam processing. By the way, the transport roller 12
1 and the discharge rollers 126 and 127 are rotated by driving the fixing motor 65. Therefore, when the warm-up is started and the fixing motor 65 is driven in the reverse direction, the transport rollers 121 and 127 are discharged. The discharge rollers 126 and 127 are also rotated in the opposite direction.

In this case, with the recording medium 21 remaining in the sheet discharge section, the transport roller 121 and the discharge roller 126
When the recording medium 21 is rotated in the reverse direction, the recording medium 21 is conveyed in the reverse direction, and the recording medium 21 is conveyed in the fixing device 48 or the conveyance belt unit 20.
The recording medium 21 is pulled into A. Therefore, in the present embodiment, when the recording medium 21 is present in the paper discharge unit, the jam processing is performed. Step S4: The control circuit 51 drives the fixing motor 65 in the reverse direction, moves the heating roller 49 in the direction of arrow 1, the pressure roller 50 in the direction of arrow m, the oil roller 116 in the direction of arrow n, and the cleaning roller 117 in the direction of arrow n. Each is rotated in the opposite direction in the p direction.

By rotating the heating roller 49 in the direction of arrow h and the pressing roller 50 in the direction of arrow i,
The anti-offset liquid oozing out of the oil roller 116 adheres to the surface of the heating roller 49, and further adheres to the surface of the pressure roller 50 at the nip between the heating roller 49 and the pressure roller 50. Then, as the heating roller 49 and the pressure roller 50 rotate, the offset preventing liquid is
If the toner particles accumulate on the surface of the recording medium 21, the back surface of the recording medium 21 will be stained by the offset prevention liquid when fixing the color toner image on the recording medium 21.

Therefore, in the present embodiment, as described above, the heating roller 49 is moved in the direction of arrow 1, the pressure roller 50 is moved in the direction of arrow m, the oil roller 116 is moved in the direction of arrow n, and the cleaning roller 117 is moved in the direction of arrow n. Each is rotated in the opposite direction in the p direction. In this case, the offset prevention liquid that has oozed out of the oil roller 116 is immediately sucked by the cleaning roller 117 disposed downstream of the oil roller 116 in the rotation direction when the heating roller 49 is rotated in the direction of arrow l. . Accordingly, it is possible to prevent the excessive offset prevention liquid from adhering to the surface of the pressure roller 50, so that the recording medium 21 is not stained by the offset prevention liquid.

The driving of the fixing motor 65 in the reverse direction is continued until the warm-up is completed. Step S5: The surface temperature _Tr detected by the thermistor 102 is _equal to the first set temperature, that is, 165 ° C.
It is determined whether or not this is the case. Surface temperature _Tr is 165
If the temperature is [° C.] or more, the process proceeds to step S6, where the surface temperature _Tr
Is lower than 165 [° C.], the process proceeds to step S7. Step S6: The fixing device barrier 61 is driven to stop the energization of the heater 101. Step S7: The fixing device barrier 61 is driven to energize the heater 101. Step S8: The surface temperature T _p detected by the thermistor 103 is equal to the second set temperature, that is, 100 ° C.
It is determined whether or not this is the case. Surface temperature T _p is 100
If [℃] or higher than that, the process proceeds to step S9, when the surface temperature T _p is less than 100 [℃] returns to step S5. Step S9: The fixing device barrier 61 is driven to stop the energization of the heater 101. Step S10: The driving of the fixing motor 65 in the reverse direction is stopped.

When the warm-up is completed in this manner, the control circuit 51 waits for a color image signal to be transmitted from the host computer. Next, a second embodiment of the present invention will be described. FIG. 5 is a flowchart showing the operation of the fixing device according to the second embodiment of the present invention,
FIG. 6 is a temperature rise characteristic diagram of the surface temperatures of the heating roller and the pressure roller according to the second embodiment of the present invention. In FIG. 6, the horizontal axis represents time, and the vertical axis represents the heating roller 4.
9 (FIG. 1) and the surface temperature of the pressure roller 50 are taken. The components having the same structure as that of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this case, the motor driving circuit 62 (FIG. 3) as the rotation state changing means drives the fixing motor 65 as a driving unit in the forward direction, and drives the heating roller 49 as the first roller of the fixing device 48. The pressure roller 50 as the second roller is rotated in the direction of the arrow i, the oil roller 116 as the coating means is rotated in the direction of the arrow j, and the cleaning roller 117 as the cleaning means is rotated in the direction of the arrow k. Direction).

The motor drive circuit 62 can switch the rotation speed of the fixing motor 65, the heating roller 49, and the pressure roller 50 by operating a rotation speed switching unit (not shown). Next, the flowchart will be described. Step S11: Turn on the AC power switch 89,
The low-voltage power supply 152 is started, and the low-voltage is controlled by the control circuit 5.
1. Print control circuits 58Y, 58M, 58C, 58B, memories 59Y, 59M, 59C, 59B and high voltage power supply 15
0 is applied to each. Then, the control circuit 51 executes a predetermined initial setting. Step S12: It is determined whether or not the recording medium 21 has passed through the paper discharge section between the guides 122 to 125. Recording medium 2
If 1 has passed, the process proceeds to step S14; otherwise, the process proceeds to step S13. Step S13: The control circuit 51 determines that a jam has occurred, displays that a jam has occurred on a display unit (not shown), and performs a jam process. Step S14: The control circuit 51 drives the fixing motor 65 at high speed. In this case, the rotation speed of the fixing motor 65 is
During printing, that is, while the transferred color toner image is fixed on the recording medium 21, the rotation speed is set higher than the rotation speed.

In FIG. 6, L1 to L3 are fixing motors 6
5 the surface temperature T _r of the heating roller 49 and the pressure roller 50 when the rotational speed is varied in a line showing the temperature rise characteristics of T _p, when the line L1 is obtained by increasing the rotational speed of the fixing motor 65 the surface temperature T _r, the temperature rise characteristic of T _p, the line L3 shows the surface temperature T _r, the temperature rise characteristic of T _p when the low rotational speed of the fixing motor 65.

[0072] Therefore, by increasing the rotational speed of the fixing motor 65, the surface temperature T _r, the 1 T _p, respectively, the time until the second predetermined temperature, i.e., required to perform the warm-up Time can be shortened. The high-speed driving of the fixing motor 65 is continued until the warm-up is completed. Also,
T _A is the time during which the heater 101 as a heating element is continuously energized, and T _B is the time during which the heater 101 is energized or de-energized. Step S15: The surface temperature _Tr detected by the thermistor 102 is _equal to the first set temperature, that is, 165.
It is judged whether it is [° C.] or more. If the surface temperature _Tr is equal to or higher than 165 ° C., the process proceeds to step S16. If the surface temperature _Tr is lower than 165 ° C., the process proceeds to step S17.
Proceed to. Step S16: The fixing device barrier 61 as a temperature control unit is driven to stop the power supply to the heater 101. Step S17: The fixing device barrier 61 is driven to energize the heater 101. Step S18: The surface temperature T _p detected by the thermistor 103 becomes the second set temperature, that is, 100
It is judged whether it is [° C.] or more. If the surface temperature T _p of 100 [℃] or the process proceeds to step S19,
If the surface temperature T _p is lower than 100 [° C.], step S
Return to 15. Step S19: The power supply to the heater 101 is stopped by driving the fixing unit barrier 61. Step S20: The driving of the fixing motor 65 in the reverse direction is stopped.

When the warm-up is completed, the control circuit 51 waits for a color image signal to be transmitted from the host computer. Next, the third aspect of the present invention
An embodiment will be described. FIG. 7 is a flowchart showing the operation of the fixing device according to the third embodiment of the present invention. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

In this case, the motor drive circuit 62 (FIG. 3) as a rotation state changing means includes a rotation direction switching means (not shown), and the fixing direction of the fixing motor 65 as a driving unit is changed by the rotation direction switching means. To the fixing device 4
8 (FIG. 1), the heating roller 49 as the first roller in the direction of arrow h, the pressure roller 50 as the second roller in the direction of arrow i, the oil roller 116 as the application means in the direction of arrow j, Cleaning roller 11 as cleaning means
7, the heating roller 49 in the direction of the arrow l, the pressure roller 50 in the direction of the arrow m, the oil roller 116 in the direction of the arrow n, and the cleaning roller 117 in the direction of the arrow. Each can be rotated in the p direction (rotated in the opposite direction).

The motor drive circuit 62 can switch the rotation speed of the fixing motor 65, the heating roller 49, and the pressure roller 50 by operating a rotation speed switching unit (not shown). Next, the flowchart will be described. Step S21: Turn on the AC power switch 89,
The low-voltage power supply 152 is started, and the low-voltage is controlled by the control circuit 5.
1. Print control circuits 58Y, 58M, 58C, 58B, memories 59Y, 59M, 59C, 59B and high voltage power supply 15
0 is applied to each. Then, the control circuit 51 executes a predetermined initial setting. Step S22: It is determined whether or not the recording medium 21 has passed the paper discharge section between the guides 122 to 125. Recording medium 2
If 1 has passed, the process proceeds to step S24; otherwise, the process proceeds to step S23. Step S23: The control circuit 51 determines that a jam has occurred, displays on the display means (not shown) that the jam has occurred, and performs jam processing. Step S24: The control circuit 51 drives the fixing motor 65 in the reverse direction and at a high speed. In this case, the motor drive circuit 62 rotates the heating roller 49 in the direction of arrow 1, the pressure roller 50 in the direction of arrow m, the oil roller 116 in the direction of arrow n, the cleaning roller 117 in the direction of arrow p, and The rotation speed of the fixing motor 65 is set higher than the rotation speed while the transferred color toner image is fixed on the recording medium 21.

Therefore, the anti-offset liquid oozing from the oil roller 116 is applied to the oil roller 1 in the rotation direction when the heating roller 49 is rotated in the direction of arrow l.
Cleaning roller 117 disposed downstream of the cleaning roller 117
Is immediately aspirated. Therefore, it is possible to prevent the excessive offset prevention liquid from adhering to the surface of the pressure roller 50, so that the back surface of the recording medium 21 is not stained by the offset prevention liquid.

[0077] Also, by increasing the rotational speed of the fixing motor 65, the surface temperature T _r of the heating roller 49 and the pressure roller 50, the 1 T _p, respectively, the time until the second predetermined temperature, i.e. Therefore, the time required for performing the warm-up can be shortened. The reverse high-speed driving of the fixing motor 65 is continued until the warm-up is completed. Step S25: It is determined whether or not the surface temperature _Tr of the heating roller 49 detected by the thermistor 102 is equal to or higher than the first set temperature, that is, 165 [° C.]. If the surface temperature _Tr of the heating roller 49 is equal to or higher than 165 [° C.], the process proceeds to step S26.
_{If r} is lower than 165 [° C.], the process proceeds to step S27. Step S26: The power supply of the heater 101 as the heating element is stopped by driving the fixing device barrier 61 as the temperature control means. Step S27: The fixing device barrier 61 is driven to energize the heater 101. Step S28: It is determined whether or not the surface temperature T _p of the pressure roller 50 detected by the thermistor 103 is equal to or higher than the second set temperature, that is, 100 ° C. If the surface temperature T _p of the pressure roller 50 is 100 [℃] or higher, the process proceeds to step S29, if the surface temperature T _p of the heating roller 50 is lower than 100 [℃] returns to step S25. Step S29: The power supply to the heater 101 is stopped by driving the fixing device barrier 61. Step S30: The high-speed driving of the fixing motor 65 is stopped.

When the warm-up is completed in this way, the control circuit 51 waits for a color image signal to be transmitted from the host computer. Next, the fourth aspect of the present invention.
An embodiment will be described. FIG. 8 is a diagram showing a power transmission system of a fixing motor according to a fourth embodiment of the present invention.

In the figure, 49 is a heating roller as a first roller, 65 is a fixing motor as a driving unit, 121
Is a transport roller, and 126 and 127 are discharge rollers. The transport roller 121 and the discharge rollers 126, 12
Reference numeral 7 denotes a recording medium transport unit. A motor gear 201 is fixed to an output shaft (not shown) of the fixing motor 65, the motor gear 201 and the idle gear 202 are meshed (engaged), and a heating roller gear 203 is fixed to a shaft (not shown) of the heating roller 49. The heating roller gear 203 and the idle gear 202 are meshed.

The shaft 204 of the transport roller 121
The first and second transport roller gears 205 and 206 are fixed, and the first transport roller gear 205 and the idle gear 207 mesh with each other, and the second transport roller gear 206 and the idle gear 202 mesh with each other. Can be Further, the shaft 208 of the discharge rollers 126 and 127
Then, the discharge roller gear 209 is fixed, and the discharge roller gear 209 is meshed with the idle gear 207.

Therefore, when the fixing motor 65 is driven in the forward direction, the rotation generated by the fixing motor 65 is transmitted to the heating roller 49 via the motor gear 201, the idle gear 202 and the heating roller gear 203 in this order. 49 is rotated in the direction of arrow h (forward direction). At this time, the rotation of the idle gear 202 is transmitted to the transport roller 121 via the second transport roller gear 206, and rotates the transport roller 121 in the direction indicated by the solid line arrow. It is transmitted to the discharge rollers 126 and 127 via the roller gear 205, the idle gear 207, and the discharge roller gear 209 in order, and rotates the discharge rollers 126 and 127 in the solid arrow direction.

On the other hand, when the fixing motor 65 is driven in the reverse direction, the rotation generated by the fixing motor 65 is transmitted to the heating roller 49 via the motor gear 201, the idle gear 202 and the heating roller gear 203 in that order. The heating roller 49 is rotated in the direction of arrow l. At this time, the idle gear 202 is rotated in the direction of the arrow shown by the broken line, and the rotation of the idle gear 202 is transmitted to the second transport roller gear 206. However, the power is transmitted between the second transport roller gear 206 and the shaft 204. The rotation transmitted to the second conveyance roller gear 206 is not transmitted to the shaft 204 because the one-way clutch (not shown) is connected as a blocking means, and the conveyance roller 121 and the discharge rollers 126 and 127 do not rotate. .

The one-way clutch transmits power when the fixing motor 65 is driven in the forward direction, and cuts off transmission of power when the fixing motor 65 is driven in the reverse direction. Note that an electromagnetic clutch or the like may be used instead of the one-way clutch. In this way, during the warm-up, the guide 122
Even if the heating roller 49 and the pressure roller 50 as the second roller are rotated in the reverse direction in a state where the recording medium 21 (FIG. Since the transport roller 121 and the discharge rollers 126 and 127 do not rotate, the recording medium 21 is not transported in the reverse direction, and the recording medium 21 is prevented from being drawn into the fixing device 48 or the transport belt unit 20A. Can be.

The present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0085]

As described above in detail, according to the present invention, in the fixing device control device, the first device including the heating element is provided.
A roller, a second roller disposed in contact with the first roller, temperature control means for selectively energizing the heating element to control a surface temperature of the first roller, 1,
A driving unit that rotates the second roller; and a rotation state changing unit that changes a rotation state of the driving unit during printing and during warm-up.

In this case, when the warm-up is started, the driving unit is driven, and the first and second rollers are rotated in the opposite directions until the warm-up is completed. Therefore, it is possible to suppress the occurrence of temperature unevenness in the surface temperatures of the first and second rollers. Further, the time required for performing warm-up can be shortened.

[Brief description of the drawings]

FIG. 1 is a first diagram illustrating a color image recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a second diagram illustrating the color image recording apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram of a color image recording apparatus according to the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation of the fixing device according to the first embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation of a fixing device according to a second embodiment of the present invention.

FIG. 6 is a temperature rise characteristic diagram of the surface temperature of a heating roller and a pressure roller according to a second embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation of a fixing device according to a third embodiment of the present invention.

FIG. 8 is a diagram illustrating a power transmission system of a fixing motor according to a fourth embodiment of the present invention.

[Explanation of symbols]

48 fixing device 49 heating roller 50 pressure roller 61 fixing device driver 62 motor drive circuit 65 fixing motor 101 heating heater 121 transport roller 126, 127 discharge roller _Tr surface temperature

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ken Nozawa 4-11-12 Shibaura, Minato-ku, Tokyo Inside the company offshore data (72) Inventor Masato Sakai 4-11-22 Shibaura, Minato-ku, Tokyo Shares (72) Inventor Shinichi Murakami 4-11-11 Shibaura, Minato-ku, Tokyo Stock Company Offshore Data (72) Inventor Junichi Ito 4-11-22 Shibaura, Minato-ku, Tokyo Stock Company Oki data

Claims (5)

[Claims] (A) a first roller having a heating element;
(B) a second roller disposed in contact with the first roller, and (c) temperature control means for selectively energizing the heating element to control a surface temperature of the first roller. (D) a drive unit for rotating the first and second rollers, and (e) a rotation state changing unit for changing the rotation state of the drive unit during printing and during warm-up. A fixing device control device, comprising: 2. The fixing device control according to claim 1, wherein the rotation state changing unit drives the driving unit in a forward direction during printing, and drives the driving unit in a reverse direction during warm-up. apparatus. 3. The fixing device according to claim 1, wherein the rotation state changing unit sets the rotation speed of the drive unit during a warm-up operation to be higher than the rotation speed of the drive unit during printing. Control device. 4. An application means for applying an offset preventing liquid to at least one of the first and second rollers, and (b) a rotation direction of the first and second rollers during printing. 3. The fixing device control device according to claim 2, further comprising a cleaning unit disposed upstream of the coating unit. 5. A recording medium conveying means disposed downstream of first and second rollers in a conveying direction of the recording medium, and (b) a position between the driving section and the recording medium conveying means. Power to transmit the power to the recording medium conveying means when the driving unit is driven in the forward direction, and to shut off the transmission of the power to the recording medium conveying means when the driving unit is driven in the reverse direction. The fixing device control device according to claim 2, further comprising a transmission blocking unit.