JPH06118761A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate troubles resulting in the incompatible actions of image formation processing devices in relation to an image carrier, in the case of reducing torque loads of a drive transmission means and a drive source at the start of a fixing device by the control of the drive of the fixing device in an image forming device which uses the fixing device of a film type as an image fixing means and drives the image carrier and fixing device of an image formation processing part by means of the same drive source. CONSTITUTION:The driving speed of the drive source 102 has at least two steps: first speed that is a normal speed at which the image formation processing part forms an image, and a second speed that is lower than the first speed. When the drive source 102 is driven at the second speed, the prescribed image- formation conditions of the image formation processing part is altered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-fixable developer image on a recording material in an image forming process section including an image bearing member such as a photoconductor, such as an electrophotographic copying machine, printer or facsimile. The present invention relates to an image forming apparatus in which a (toner image) is formed and carried, and the recording material is subjected to an image fixing process by a heat fixing unit.

More specifically, the heat fixing means is a film type fixing device, and at least the image carrier of the image forming process section and the film type fixing device are driven by the same driving source. Regarding the device.

[0003]

2. Description of the Related Art A film type fixing device is disclosed in, for example, Japanese Patent Laid-Open No. 63-
Known from JP-A-313182 and JP-A-2-157878, it has a heating body and a heat-resistant fixing film that is driven to move in contact with the heating body, and adheres a recording material through the fixing film. Then, the heating member is moved through the fixing film together with the fixing film, and the heat of the heating member is applied to the recording material through the fixing film to heat and fix the heat-fixing developer image on the recording material. It is one of the effective means for image heat fixing processing, and has already been put to practical use.

[0004]

The film-type fixing device is a heat-resistant fluorine-based fixing agent used as a lubricant in the close contact sliding portion between the heating body and the fixing film in order to reduce the sliding friction resistance between the fixing film and the heating body. Although grease or the like is interposed, due to the characteristics of the grease, the viscosity of the grease is large at low temperatures, so a considerable amount of time has elapsed from the end of the previous image formation, such as when performing an image forming operation in the morning. When the heating element of the fixing device is cold, the viscosity of the grease is high, and the momentary torque when the fixing device is started becomes large.

For this reason, it is necessary to increase the strength of the drive transmission means, such as gears, or increase the drive torque of the motor or the like as a drive source, which causes the drawbacks of increasing the size and cost of the device.

As a solution to this drawback, when the temperature of the heating element of the fixing device is low, the fixing device is driven at a speed lower than the normal driving speed (normal image forming speed), or is driven. By setting the control configuration such that the fixing device is stopped and driven at a normal drive speed when the temperature of the heating element of the fixing device rises to a predetermined value, the torque burden of the drive transmission means and the drive source at the time of starting the fixing device is reduced. Can be mitigated.

However, at least in the case of an image forming apparatus in which the image carrier of the image forming process section and the fixing device are driven by the same drive source, the fixing device is controlled by the speed control of the drive source. When the low-speed drive state or the drive stop state is set, the image carrier also enters the low-speed drive state or the drive stop state, which causes incompatibility in the action of the image forming process device on the image carrier.

For example, when a high voltage is applied to the potential applying means to the image carrier as in a normal state when the image carrier is driven at a low speed or is in a drive stopped state, the image carrier is damaged. there is a possibility. Further, if the exposure is carried out as usual, the characteristics of the surface of the image carrier may be deteriorated.

The present invention relates to an image forming apparatus in which a film type fixing device is used as the image fixing means and the image carrier and the fixing device of the image forming process section are driven by the same drive source, as described above. By controlling the driving of the fixing device, the torque load on the drive transmission means and the driving source at the time of starting the fixing device is reduced. However, in this case, it is caused by the incompatibility of the image forming process equipment with the image carrier. It is an object of the present invention to provide an image forming apparatus that eliminates the above problems.

[0010]

The present invention is an image forming apparatus having the following configuration. (1) An image forming apparatus in which a heat-fixing developer image is formed and carried on a recording material in an image forming process section including an image bearing member, and the recording material is subjected to image fixing processing by the heating fixing means. Has a heating body and a heat-resistant fixing film that is moved and driven in contact with the heating body. The recording material is brought into close contact with the heating body through the fixing film, and is moved through the heating body position together with the fixing film. A film-type fixing device for applying heat of a heating body to a recording material through a fixing film to heat and fix a heat-fixable developer image on the recording material, at least an image carrier of the image forming process section. And the fixing device is driven by the same drive source, and the drive speed of the drive source is at least a first speed that is a normal image forming speed of the image forming process unit and a second speed that is lower than the first speed. Has two stages Image forming apparatus and changes the predetermined image forming condition of image forming process unit when said driving source is driven at a second speed.

(2) A means for detecting the temperature of the heating element of the fixing device is provided, and when the temperature of the heating element is lower than a predetermined temperature, the driving source is driven at the second speed.
When the temperature of the heating body reaches a predetermined temperature, a means for switching the drive of the drive source to the first speed is provided, and when the temperature of the heating body is equal to or lower than the predetermined temperature, the predetermined image forming condition of the image forming process unit is set. The image forming apparatus according to (1), further including a changing unit.

(3) The image forming apparatus described in (1) or (2), wherein the image forming condition is an exposure condition for the image carrier.

(4) The image forming apparatus according to (1) or (2), wherein the image forming condition is a condition for applying a potential to the image carrier.

(5) The image forming apparatus as described in (1) or (2), characterized in that exposure and potential application to the image carrier are not performed during driving at the second speed.

(6) An image forming apparatus in which an image forming process section including an image bearing member forms and carries a heat-fixing developer image on a recording material, and the recording material is subjected to an image fixing process by a heat-fixing means. The heating and fixing means has a heating body and a heat-resistant fixing film which is driven to move in contact with the heating body, and the recording material is brought into close contact with the heating body through the fixing film so that the position of the heating body is fixed together with the fixing film. A film-type fixing device for moving and passing heat of a heating body to a recording material through a fixing film to heat-fix a heat-fixable developer image on the recording material, at least the image forming process section The image carrier and the fixing device are driven by the same drive source,
When the temperature detected by the temperature detecting means is lower than a predetermined value, the drive source is not driven and the temperature of the heating body is set to a predetermined value. An image forming apparatus, which starts driving a drive source to perform an image forming operation when the temperature exceeds the temperature.

(7) While the temperature of the heating element is below a predetermined temperature and the driving source is not driven, the exposure amount of the exposure lamp of the image forming process section is changed so that the temperature of the heating element becomes equal to or higher than the predetermined temperature. The image forming apparatus described in (6) is characterized in that the exposure lamp is turned on at a normal exposure amount when the drive source is driven.

(8) While the temperature of the heating element is below a predetermined temperature and the drive source is not driven, the output level of the high voltage to the potential applying means to the image carrier of the image forming process section is changed to change the heating element. The image forming apparatus described in (6) is characterized in that the high voltage is output at a normal level when the temperature of the temperature exceeds a predetermined temperature and the drive source is driven.

[0018]

[Operation] That is, when the temperature of the heating element of the fixing device is lower than the predetermined temperature, the driving speed of the driving source is set to the second speed which is lower than the first speed which is the normal image forming speed, or is driven. When the fixing device is brought into the stopped state and is driven at a low speed or is kept in the stopped state, and when the temperature of the heating body of the fixing device reaches a predetermined temperature, the driving speed of the driving source is set to the normal first speed.
By controlling the speed to the normal drive state of the fixing device, the torque load of the drive transmitting means and the drive source at the time of starting the fixing device is reduced, the strength of the drive transmitting means is further increased, and the drive source is driven. There is no need to further increase the torque, and the device can be downsized and the cost can be reduced.

.. While the image carrier is driven at a low speed or is stopped due to the drive control or the drive stop control of the drive source at the second speed, a predetermined image forming condition of the image forming process unit is changed, for example, image carrying. The conditions for applying a high voltage to the potential applying means for the body, the exposure conditions for the image carrier, etc. are changed to conditions that are suitable for the low speed drive state or the drive stopped state of the image carrier (for applying the potential or exposing the image carrier). Including the case where it is not performed), problems such as damage of the image carrier and deterioration of characteristics due to incompatibility of image forming process equipment with respect to the image carrier that is in the low speed drive state or the drive stop state may occur. Will be resolved.

[0020]. As drive source control, the above (6) to
As in the apparatus described in (8), when the heating body of the fixing device is lower than a predetermined temperature, the drive source is not driven, that is, the fixing device and the image carrier are both kept in a stopped state. In the case of on / off control that starts driving of the driving source when the temperature of the heating element exceeds a predetermined temperature, compared with the control that switches the speed of the driving source at least between the normal speed and the low speed. For example, a low-speed drive circuit is not needed, the configuration of the drive circuit / control circuit, etc. can be simplified and the cost can be reduced.

[0021]

【Example】

A. The following first to third embodiments are embodiments of the image forming apparatus characterized by the configurations described in claims 1 to 5 of the claims.

<First Embodiment> (FIGS. 1 to 6) (1) Example of Image Forming Apparatus (FIG. 1) FIG. 1 is a schematic configuration of an example of an image forming apparatus using a film type fixing device as an image fixing means. It is a figure. The image forming apparatus of this example is a reciprocating platen / rotating drum type / transfer type electrophotographic copying apparatus.

Reference numeral 100 denotes an apparatus casing, and 1 denotes a reciprocating type document placing table made of a transparent plate member such as a glass plate disposed on an upper surface plate 100a of the apparatus casing.
The upper part is driven to reciprocate to the right a and the left a'in the drawing at a predetermined speed.

Reference numeral G denotes an original, which is placed on the upper surface of the original placing table 1 with the image surface side to be copied facing downward according to a predetermined placing standard, and the original pressure plate 1a is placed on the original and placed thereon. Set.

Reference numeral 100b denotes a slit opening serving as a document illuminating section which is opened on the surface of the machine top plate 100a with a direction perpendicular to the reciprocating direction of the document placing table 1 (direction perpendicular to the paper surface) as a longitudinal direction.

The downward image surface of the document G placed and set on the document placing table 1 is sequentially subjected to the slit opening 10 from the right side to the left side in the forward movement process of the document placing table 1 to the right a.
0b, the light L of the fluorescent lamp (exposure lamp) 3 is passed through the slit opening 100b,
It is received and scanned by illumination through the transparent original placing table 1. The light reflected from the document surface of the illumination scanning light is transferred to the photosensitive drum (photosensitive member) 4 as an image carrier by the short-focus small-diameter image forming element array 2.
The image is exposed on the surface.

The photosensitive drum 4 is coated with a photosensitive layer such as a zinc oxide photosensitive layer and an organic semiconductor photosensitive layer, and the central support shaft 4
Shown at a predetermined process speed (peripheral speed) around a
Is rotated clockwise, and in the course of the rotation, a uniform charging process of positive or negative polarity is performed by a charger 5 as a potential applying means, and the uniformly charged surface is imagewise exposed to the original image ( Photosensitive drum 4 by receiving slit exposure)
An electrostatic latent image corresponding to the original image image-exposed and formed is sequentially formed on the surface.

This electrostatic latent image is sequentially visualized by the developing device 6 with toner as a heat-fixing developer made of resin or the like that is softened and melted by heating, and the toner image as the visualized image is used as a transfer portion. Of the transfer discharger 9.

Reference numeral S denotes a cassette in which transfer material sheets P as recording materials are stacked and accommodated. The sheets in the cassette are fed out and fed one by one by the rotation of the feeding roller 7, and then the registration roller 8 causes the drum 4 to move. When the tip of the upper toner image forming portion reaches the portion of the transfer discharger 9, the tip of the transfer material sheet P also arrives at the position between the transfer discharger 9 and the photosensitive drum 4, and the timing is adjusted so that they coincide with each other. It is then delivered synchronously. Then, the transfer discharger 9 sequentially transfers the toner image on the photosensitive drum 4 side to the surface of the fed sheet.

The sheet to which the toner image has been transferred at the transfer portion is sequentially separated from the surface of the photosensitive drum 4 by a separating means (not shown), and is guided to a fixing device 11 described later by a conveying device 10 to carry the unfixed toner. The image is subjected to heat fixing processing, and is discharged as an image-formed product onto the paper discharge tray 12 outside the machine through the guide 43 and the discharge roller 44.

The surface of the photosensitive drum 4 after the image transfer is subjected to removal of adhered contaminants such as transfer residual toner by the cleaning device 13 and is repeatedly used for image formation.

(2) Fixing Device 11 (FIGS. 2 to 4) FIG. 2 is a schematic configuration diagram of the fixing device 11. FIG. 3 is a plan view in which an intermediate part of the heating element (heater) is viewed from the side where the energized heating element layer is formed.

Reference numeral 25 denotes a heat-resistant fixing film in the form of an endless belt, which has a low driving capacity on the left side, a driven roller on the right side 27, and a low heat capacity fixedly supported below both rollers 26, 27. The heater 21 as a linear heating element and a guide roller 26a arranged below the drive roller 26 are arranged in parallel with each other by the four members 26.
Suspended between 27, 21 and 26a.

The driven roller 27 also serves as a tension roller for the endless belt-shaped fixing film 25.
The fixing film 25 is a recording material having an unfixed toner image Ta conveyed from the image forming section (9) side on the upper surface thereof at a predetermined peripheral speed in the clockwise direction with the clockwise rotation of the driving roller 26. The transfer material sheet P is rotationally driven at the same peripheral speed as the conveying speed of the transfer material sheet P without wrinkles, meandering, or speed delay.

Numeral 28 is a pressure roller as a pressure member having a rubber elastic layer having a good releasability such as silicon rubber, and sandwiching the film portion on the descending side of the endless belt-shaped fixing film 25, and the heater. The lower surface of the sheet 21 is pressed against the lower surface of the sheet 21 by urging means with a contact pressure of, for example, 4 to 7 kg in total, and rotates in the forward counterclockwise direction in the transport direction of the transfer material sheet P.

Since the endless belt-shaped fixing film 25 which is rotationally driven is repeatedly subjected to heat fixing of the toner image, it has excellent heat resistance, releasability and durability, and generally has a total thickness of 100 μm or less, Preferably, a thin monolayer or composite layer film of less than 40 μm is used.

In this embodiment, polyimide, polyether imide, PES, PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin) or the like is used to form a PT on the image contact surface side of a heat-resistant resin film having a thickness of about 20 μm.
A release coating layer such as FE (tetrafluoroethylene resin) / PAF is applied to a thickness of about 10 μm.

The heater 21 as a heating body in this example is a heater substrate 22 having an insulating property, a high heat resistance, and a low heat capacity, the length of which is the direction orthogonal to the transfer material sheet P conveying direction.
And a heater temperature detecting element provided by contacting an energization heating element layer 23 formed by printing along the length of the substrate surface and a surface of the substrate 22 opposite to the energization heating element layer formation surface side. The basic structure of the thermistor 24 is of low heat capacity, and the heater 21 is held in the heater holder 30 by exposing the side of the surface where the electric heating element layer is formed.

The heater holder 30 holds the heater 21 adiabatically, and is made of a highly heat-resistant resin such as PPS (polyphenylene sulfide), PAI (polyamide imide), PI (polyimide), PEEK (polyether ether ketone) and liquid crystal polymer. Or a composite material of these resins and ceramic metal, glass, or the like.

The heater substrate 22 has a thickness of 1 mm as an example.
An alumina substrate with a width of 6 mm and a length of 240 mm. Further, it is a composite material substrate including the same.

As shown in FIG. 3, the energization heat generating layer 23 is formed along the longitudinal direction at the substantially central portion of the lower surface of the heater substrate 22, for example, Ag.
/ Pd, RuO ₂ , Ta ₂ N, etc.
It is provided by coating (screen printing, etc.) on m.
Power supply electrodes 23a and 23b provided by energizing both ends thereof
A voltage is applied between them to energize them.

The energization is controlled by the temperature detecting element 24, and the energy temperature of the heater 21 is controlled by supplying electric power according to a desired amount of temperature energy emission.

The surface of the heater 21 on which the electric heating layer 23 is formed may be covered with a surface protective layer such as a thin heat-resistant glass in order to prevent abrasion of the film 25 due to sliding conveyance.

A lubricant is applied to the sliding surface of the heater 21 that contacts the fixing film.

The image forming process is executed by the image forming start signal, and the transfer material sheet P conveyed from the transfer section (9) side to the fixing device 11 is guided by the inlet guide 29 and is heated by the temperature-controlled heater 21. The unfixed toner image surface moves in the same direction at the same speed as the conveyance speed of the sheet P by entering between the fixing roller 25 and the pressure roller 28 at the pressure contact portion N (fixing nip portion) with the pressure roller 28. The heater 2 is in close contact with the lower surface of the film 25 in the state of being in a state of overlapping with the film 25 without causing surface deviation or wrinkling.
1 passes through the fixing nip portion N between the pressure roller 1 and the pressure roller 28 while receiving a clamping pressure.

The toner image bearing surface of the sheet P receives the heat of the heater 21 through the film 25 in the process of passing through the fixing nip portion N in a pressed contact state with the film surface, the toner image is melted at a high temperature, and the sheet P is heated. The surface is softened and adhered to Tb.

In the case of the apparatus of this example, the sheet P as a recording material and the film 25 are separated from each other when the sheet P passes through the fixing nip portion N and comes out.

The sheet P separated from the film 25 is guided by the guide 43, and the temperature of the toner Tb higher than the glass transition point is naturally lowered (naturally cooled) while reaching the pair of discharge rollers (44), so that the glass transition occurs. The temperature below the point is reached and solidification Tc is reached, and the sheet P on which the image has been fixed is output onto the tray.

The film 25 is not limited to the endless belt shape, and as shown in FIG. 4, the end fixing film 25 wound around the delivery shaft 41 in a roll is passed between the heater 21 and the pressure roller 28. Lock it on the winding shaft 42,
Transfer material sheet P from delivery shaft 41 side to winding shaft 42 side
It may be configured to run at the same speed as the transport speed of.

(3) Control System (FIG. 5) FIG. 5 is a block diagram of a control system such as a motor control unit, a high-voltage power supply unit, an exposure lamp power supply unit, and a heater control unit in the apparatus of this embodiment.

Reference numeral 101 is a control unit (CPU) for controlling the overall operation of the image forming apparatus, 102 is a main motor as a drive source for driving the fixing device 11, the photosensitive drum 4, and other loads, and 103 is a main motor. An encoder for detecting the number of rotations of the motor 102, 104 is the main motor 1
This is a circuit for controlling the number of revolutions (speed) of 02.

The operation will be described. M_ON of CPU 101
"H" is output from the terminal and the motor speed control circuit 104
When the signal is received at, the drive signal is output from the M_D terminal to the transistor 111, and the main motor 102 is driven.

At this time, the encoder 103 detects the number of rotations of the motor 102, and based on this, the control circuit 104
To control the speed.

When the output of the V_H terminal of the CPU 101 is "L", the control speed of the motor 102 is low (second speed).
Speed), and when it is "H", it is switched to the normal control speed (first speed) for image formation.

In the control circuit 104, the encoder 103
Discriminates whether the number of rotations detected is normal drive speed or low speed drive, and at the time of low speed drive, it is "L" from the V_HO terminal.
Is output, and "H" is output at the normal driving speed.

Reference numeral 106 is a high-voltage power supply, which creates a high voltage to be applied to the photosensitive drum 4 and supplies it to the charger 5. The output of this high-voltage power supply 106 is turned on / off by the CPU.
P_ON 'terminal of 101 and motor speed control circuit 104
The output of the V_HO terminal is controlled by gated by the gate 105.

In this embodiment, when both the outputs of the P_ON 'terminal and the V_HO terminal are "H", the output of the gate 105, that is, the input terminal P_ON input of the high voltage power supply 106 becomes "H", and the photosensitive drum primary from P_OUT. The high voltage for charging is output to the primary charger 5.

Reference numeral 21 is a heating body (heater) of the fixing device 11, 24 is a thermistor for detecting the temperature of the heating body 21,
Reference numeral 110 is a power source for supplying electric power to the energization heat generating body 23 of the heating body 21.

For temperature control, the temperature detected by the thermistor 24 is converted into a digital signal by the A / D converter 115, and the CPU
The TH_S terminal 101 reads the control signal based on the data from the TH_C terminal and controls the output power in the heater power supply 110 to control the temperature of the heating element 21.

Reference numeral 200 is a power source for the exposure lamp 3, and CP
The lamp 3 is turned on when the L_ON terminal of U101 is "H". Further, when L_CH is “H”, the light is turned on with the light amount for normal image formation, and when it is “L”, the power supplied to the lamp 3 is controlled so as to reduce the light amount.

(4) Control Operation (FIG. 6) Next, the actual operation will be described with reference to the flowchart of FIG.

First, when the copy key is turned on in step S1, it is compared in step S2 whether the temperature of the thermistor 24 is higher than a predetermined value T _REF . If it is lower than T _REF , the V_H terminal is set to "L" in step S3, and M_ON, P_ON, and L_ON are set to "H" in step S4.

In this state, since the motor 102 is driven at a low speed, V_ of the motor speed control circuit 104 is
The HO terminal is "L", and P_ of the high voltage power supply 106
Since the ON terminal is "L", no high voltage is output from the high voltage power supply 106.

Since the L_CH terminal of the lamp power source 200 is also "L", the exposure amount of the lamp 3 is lower than the normal exposure amount.

Next, when it is detected in step S5 that the temperature of the heating element 21 becomes higher than a predetermined value, step S5 is performed.
In step 6, the V_H terminal of the CPU 101 is set to "H", and the drive speed of the motor 102 becomes the drive speed during normal image formation. At this time, the V_HO terminal of the control circuit 104 is "H", and the P_ON terminal of the high-voltage power supply 106,
Since both the L_CH terminals of the lamp power supply 200 and the L_CH terminal are "H", the high voltage output and the exposure amount are the same as in the normal image formation.

If the temperature of the heating element 21 is higher than the predetermined temperature at step S2, the CPU 10 is turned on at step S7.
Since the V_H terminal of 1 is set to "H", the motor 1
The image forming conditions such as the drive speed of 02, the high voltage output to the charging device 5, and the exposure amount of the exposure lamp 3 are the same as those at the time of normal image formation from the beginning.

<Second Embodiment> (FIGS. 7 and 8) FIG. 7 is a block diagram of a control system of the image forming apparatus in this embodiment.

Reference numeral 250 denotes a power source for the exposure lamp 3, which is L
The lamp 3 is turned on when the _ON terminal is "H". 251 is an AND gate, which is L_ON of the CPU 101.
When both the ‘terminal and the V_HO terminal of the motor speed control circuit 104 are“ H ”, the“ H ”signal is transmitted to the L_ON terminal of the lamp power supply 250.

Next, the operation will be described with reference to the flowchart of FIG. When the copy key is turned on in step S1, the temperature of the heating element 21 is detected in step S2, and the heating element 21 is detected.
If the temperature is lower than the predetermined value, C in step S3
The V_H terminal of PU101 is set to "L".

In step S4, M_ON, L_ON, P_
Set the ON terminals to "H". At this time, the driving speed of the motor 102 is low, and the V_HO terminal of the motor speed control circuit 104 is "L".
P_OUT terminal of high-voltage power supply 106 and power supply 2 for lamp
The L_ON terminals of 50 are both "L", and the high voltage output to the charger 5 and the exposure lamp 3 are not turned on.

When it is detected in step S5 that the temperature of the heating element 21 exceeds a predetermined value, C is detected in step S6.
The V_H terminal of the PU 101 is set to "H", and the drive speed of the motor 102 is switched to the speed during image formation. At this time, the V_HO terminal of the motor speed control circuit 104 becomes "H", and the high voltage output to the charger 3 and the exposure lamp 3 are turned on.

If the temperature of the heating element 21 exceeds the predetermined value in step S2, the CPU 101 operates in step S7.
Since the V_H terminal of is set to "H", the motor 10
The driving speed of 2 becomes the speed at the time of image formation from the beginning, and the high voltage output to the charger 5 and the lighting of the exposure lamp 3 are performed in the same manner as at the time of normal image formation.

<Third Embodiment> (FIGS. 9 and 10) FIG. 9 is a block diagram of a control system of the image forming apparatus in this embodiment.

Reference numeral 120 denotes a comparator, which compares the signal from the thermistor 24 with the reference voltage 121, and outputs "L" when the detected temperature of the thermistor 24 is lower than a predetermined temperature, and outputs "H" when it is higher than the predetermined temperature. .

The output of the comparator 120 is the V_H terminal of the motor speed control circuit 104, the gate 105 and the same 25.
Connected to 3.

Next, the operation will be described with reference to the flowchart of FIG. When the copy key is turned on in step S1, M_ON and P_ON of the CPU 101 are set in step S2.
The terminals 'and L_ON' are set to "H".

At this time, when the temperature detected by the thermistor 24 is lower than the predetermined value, V_H of the motor speed control circuit 104 is increased.
Terminal, P_ON terminal of high-voltage power supply, and lamp power supply 20
Since the L_ON terminals of 0 are all "L", the motor 102 is driven at a low speed, and the high voltage is not applied to the charger 5 and the exposure lamp 3 is not turned on.

When the temperature of the heating element 21 rises and exceeds a predetermined temperature, the output of the comparator 120 becomes "H", and "H" is input to each terminal of V_H, P_ON, and L_ON. The driving speed of 102 becomes a speed for normal image formation, a high voltage is applied to the primary charger 5 of the photosensitive drum 4, and the exposure lamp 3 is also turned on.

In the first to third embodiments described above, for convenience of explanation, only one system of high voltage is described for the primary charger, but all high voltages applied to the photosensitive drum 4 (primary charging voltage , Transfer voltage, etc.).

As described above, in the image forming apparatus in which the fixing device 11 and the photoconductor 4 are driven by the same driving source 102 in the first to third embodiments, the driving source 102
However, when driving at low speed, the exposure lamp 3 lights up,
Also, since no high voltage is applied to the photoconductor 4, deterioration or damage of the photoconductor can be prevented.

B. The following fourth and fifth embodiments are embodiments of the image forming apparatus according to claims 6 to 8 of the claims.

<Fourth Embodiment> (FIGS. 11 and 12) The construction of the image forming apparatus and the construction of the fixing device 11 are the same as those of the first embodiment.
1 to 4 of the embodiment of FIG.

FIG. 11 is a block diagram of a motor drive section and a heater control section in the image forming apparatus of this embodiment. An operation unit 300 is provided. Motor drive circuit 104A
Receives the "H" signal from the ON terminal, the motor 102
Supply power to. The electric power supplied to the motor 102 is detected by the encoder 103. Motor 102
The rotation speed of the motor 102 is controlled at a constant speed.

The heater power source 110 is the control circuit 101.
When the H_ON terminal of is at "H", electric power is supplied to the heating body 21. The temperature of the heating element 21 is controlled by inputting the temperature detected by the thermistor 24 to the TC terminal of the control circuit 101 and outputting a control signal from the HP terminal of the control circuit 101 to the heater power supply 110 according to the value. .

Next, the operation will be described with reference to the flowchart of FIG. First, when the copy key is pressed in step S1, the H_ON terminal is set to "H" and power is supplied to the heating body 21 in step S2.

In step S3, the temperature of the heating element 21 waits until it reaches a predetermined value t1, and when it reaches t1, the M_ON terminal is set to "H" in step S4, the motor 102 is driven, and the image forming operation is started. It

<Fifth Embodiment> (FIGS. 13 and 14) FIG. 13 is a block diagram of a control system of the image forming apparatus in this embodiment.

The TS terminal of the control circuit 101 is set to "H" when the temperature of the heating element 21 exceeds a predetermined temperature t1. The lamp power supply 200 turns on the exposure lamp 3 when the OH terminal is "H". The high voltage power supply 106 outputs a high voltage to the charger 5 when the ON terminal is “H”.

Next, the operation will be described with reference to the flowchart of FIG. When the copy key is turned on in step S1, the H_ON, M_ON, and L_ON terminals are set to "H" and the TS terminal is set to "L" in step S2.

At this time, the M_ON terminal and the L_ON terminal are "H", but the gates 401 and 402 respectively.
The ON terminal of the motor drive circuit 104A and the ON terminal of the lamp power supply 200 are "L" because they are gated by, and the motor 102 is not driven,
The exposure lamp 3 is not turned on either.

Next, in step S3, if the temperature of the heating element 21 is equal to or lower than the predetermined temperature t1, wait until t1 is reached, and if t1 or higher is set, the TS terminal is set to "H" in step S4, and the motor 102 is driven. Then, the exposure lamp 3 is also driven.

The high voltage output from the high voltage power supply 106 to the charger 5 is output by the control signal of the HV_ON terminal which is output at a timing different from that of the flowchart of FIG. Since this control signal is gated by the gate 403, no high voltage is output when the motor 102 is not driven.

In this embodiment, the exposure lamp 3 is not turned on and the high voltage is not output to the charger 5 when the motor 102 is not driven.
It is also possible to adopt a configuration in which the amount of light and the output level to the charger 5 are changed.

As described above, in the fourth and fifth embodiments, the fixing device 11 and the photosensitive drum 4 have the same drive source 10.
In the image forming apparatus driven by 2, the fixing device 1
When the temperature of the heating element 21 of No. 1 is below a predetermined temperature, the heating element 2
By preventing the motor 102 from being driven until the temperature of 1 reaches a predetermined temperature or higher, it is possible to prevent an excessive load from being applied to the motor 102 and a gear as a drive transmission means at a low temperature with a simple and inexpensive structure. be able to.

[0095]

As described above, according to the present invention, a film type fixing device is used as the image fixing means, and the image carrier and the fixing device of the image forming process section are driven by the same drive source. In regard to the above, the problem caused by the incompatibility of the operation of the image forming process device with respect to the image carrier in the case of controlling the drive of the fixing device to reduce the torque load of the drive transmission means and the drive source at the time of starting the fixing device is solved. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a block diagram of a film type fixing device.

FIG. 3 is a plan view of the heating element (heater) with an energized heating element layer formation surface side omitted

FIG. 4 is another configuration diagram of the fixing device.

FIG. 5: Block diagram of control system

FIG. 6 is a flowchart of control operation

FIG. 7 is a block diagram of a control system of the image forming apparatus according to the second embodiment.

FIG. 8 is a flowchart of control operation

FIG. 9 is a block diagram of a control system of the image forming apparatus according to the third embodiment.

FIG. 10 is a flowchart of control operation

FIG. 11 is a block diagram of a control system of the image forming apparatus according to the fourth embodiment.

FIG. 12 is a flowchart of control operation

FIG. 13 is a block diagram of a control system of the image forming apparatus according to the fifth embodiment.

FIG. 14 is a flowchart of control operation

[Explanation of symbols]

 3 Exposure Lamp 4 Photosensitive Drum as Image Carrier 5 Charger 11 Film Fixing Device 21 Heater (Heater) 25 Fixing Film P Recording Material (Transfer Material Sheet) Ta Toner Image 101 Control Circuit (CPU) 102 Main Motor 103 Encoder 104 motor speed control circuit 104A motor drive circuit 106 high-voltage power supply 110 heater power supply 200 lamp power supply

Claims (8)

[Claims] 1. An image forming apparatus for forming and carrying a heat-fixing developer image on a recording material in an image forming process section including an image carrier, and performing an image fixing process on the recording material by a heating and fixing means. The fixing unit has a heating body and a heat-resistant fixing film that is driven to move in contact with the heating body. The recording material is brought into close contact with the heating body via the fixing film and moves the heating body position together with the fixing film. A film-type fixing device for passing the heat of a heating body to a recording material through a fixing film to heat-fix the image of the heat-fixing developer on the recording material, at least the image of the image forming process section. The carrier and the fixing device are driven by the same drive source, and the drive speed of the drive source is at least a first speed that is a normal image forming speed of the image forming process unit and a lower speed than the first speed. 2-speed 2-step It has an image forming apparatus and changes the predetermined image forming condition of image forming process unit when said driving source is driven at a second speed. 2. A means for detecting a temperature of a heating body of the fixing device, wherein when the temperature of the heating body is lower than a predetermined temperature, the driving source is driven at a second speed to heat the heating body. When the temperature of the body reaches a predetermined temperature, a means for switching the drive of the drive source to the first speed is provided, and when the temperature of the heating body is below the predetermined temperature, the predetermined image forming condition of the image forming process unit is changed. A means for performing
The image forming apparatus according to item 1. 3. The image forming apparatus according to claim 1, wherein the image forming condition is an exposing condition for the image carrier. 4. The image forming apparatus according to claim 1, wherein the image forming condition is a condition for applying a potential to the image carrier. 5. The image forming apparatus according to claim 1 or 2, wherein exposure and potential application to the image carrier are not performed during driving at the second speed. 6. An image forming apparatus for forming and carrying a heat-fixing developer image on a recording material in an image forming process section including an image carrier, and performing an image fixing process on the recording material by a heat-fixing means. The fixing unit has a heating body and a heat-resistant fixing film that is driven to move in contact with the heating body. The recording material is brought into close contact with the heating body via the fixing film and moves the heating body position together with the fixing film. A film-type fixing device for passing the heat of a heating body to a recording material through a fixing film to heat-fix the image of the heat-fixing developer on the recording material, at least the image of the image forming process section. The carrier and the fixing device are driven by the same drive source, and have a means for detecting the temperature of the heating body of the fixing device, and the temperature detected by the temperature detecting means is lower than a predetermined value. When the drive Without the drive, the temperature of the heating body is an image forming apparatus, characterized in that to perform starting image forming operation driving of the drive source When equal to or higher than a predetermined temperature. 7. While the temperature of the heating element is below a predetermined temperature and the drive source is not driven, the exposure amount of the exposure lamp of the image forming process section is changed so that the temperature of the heating element becomes equal to or higher than the predetermined temperature. The image forming apparatus according to claim 6, wherein the exposure lamp is turned on at a normal exposure amount when the source is driven. 8. The output level of the high voltage to the means for applying a potential to the image carrier of the image forming process section is changed while the temperature of the heating element is below a predetermined temperature and the drive source is not driven,
7. The image forming apparatus according to claim 6, wherein a high voltage is output at a normal level when the temperature of the heating element exceeds a predetermined temperature and the drive source is driven.