JP2962882B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copier, a facsimile machine, a printer, and a word processor having a printer function for copying and reproducing data, text, images, etc. on a recording material such as paper or resin by electrophotography. The present invention relates to a forming apparatus.

[0002]

2. Description of the Related Art Conventionally, when a toner image is thermally fixed on a recording material, a heat source is incorporated in one or both of a pair of rollers provided opposite to each other, and the toner image is formed by a roller heated by the heat source. A method of heating and fixing has been used.

However, a large amount of electric power is required due to the need for heat capacity, and most of the heat does not contribute to fixing and is not only wasted, but also increases the temperature inside the apparatus and adversely affects the surroundings. There was a problem of exerting.

In order to solve this problem, recently, as a heating element of a toner image heating / fixing means, a heat-resistant and high-thermal-conductivity substrate is provided on a surface which is in pressure contact with a pressing member via a fixing film of the substrate. There is a fixing device having a temperature detector disposed and a heating element having a low heat capacity disposed on a substrate surface opposite to the temperature detector side (see Japanese Patent Application Laid-Open No. 2-154284).

[0005]

According to the above-mentioned prior art, unnecessary heat generation is reduced, but heat is not generated corresponding to dots or fonts. Also, there is a problem in the durability of the film.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of preventing wasteful heat generation and performing more efficient heat fixing.

[0007]

According to a first aspect of the present invention, there is provided an image forming apparatus having a heating element for transferring a toner image formed on an image bearing member to a recording material and fixing by heating. Are arranged in a plurality of rows in the moving direction of the toner image on the recording material, extend in the direction intersecting and are divided in the same direction, and are arranged between the heating body and a pressure contact body for pressing the recording material against the heating body. The heating member is controlled such that a portion corresponding to a portion through which the toner image passes generates heat, and the plurality of rows of heating members are firstly passed through the first portion through which the toner image passes. An image forming apparatus comprising: a row heating body; and a second row heating body through which a toner image passes next, wherein the first row heating body has a heating temperature lower than a temperature at which the toner image melts. is there.

A second invention is a heating method for transferring a toner image formed on an image carrier to an intermediate transfer member, and thereafter re-transferring the toner image on the intermediate transfer member to a recording material and heating and fixing the toner image. In the image forming apparatus, the heating elements are arranged in a plurality of rows in the moving direction of the toner image on the intermediate transfer body, extend in the intersecting direction and are divided in the same direction, and the heating elements are The recording material is in contact with the intermediate transfer member and the heating member, and the heating member is controlled such that a portion corresponding to a portion through which the toner image passes generates heat. Multiple rows of heating elements
A first-row heating element through which a toner image passes first, and a second-row heating element through which a toner image passes next, wherein the first-row heating element has a heating temperature lower than a temperature at which the toner image melts. An image forming apparatus characterized in that:

[0009]

According to the present invention, when the toner image on the intermediate transfer member or the recording material comes to a position facing or near the heating member, the timing at which the elements of the heating member start to generate heat, the amount of heat generated, and the time during which the heat is generated , Order of heat generation, range of heat generation, etc. are selected from a predetermined sequence, and data and programs stored in the memory are selected and controlled by an external input signal or a signal from a sensor, and recorded. It is possible to efficiently heat the toner on the material.

[0010]

FIG. 1 is a diagram showing a first embodiment to which the present invention can be applied.

The photoreceptor 1 is exposed by the LED head 2 to form a latent image, which is developed by a developing roller 3 having a toner hopper (not shown) for accommodating toner, thereby forming a toner image. The toner image rotates with the rotation of the photoconductor 1, is transferred to a belt-shaped intermediate transfer member 5 stretched over a transfer roller 4 provided opposite to the photoconductor 1, and rotates in synchronization with the photoconductor. The heating member 6 rotates together with the moving belt-shaped intermediate transfer member 5.
And a fixing roller 7 provided opposite to the heating element 6 to transfer and fix the recording material 8. Around the photoreceptor, there are a main charger (not shown) for charging the photoreceptor and a cleaning member (not shown) for cleaning a toner image adhered to the photoreceptor.

The belt-shaped intermediate transfer member 5 is a transfer roller 4
, A heating element 6 and a tension roller 9 to which a force is applied in a direction indicated by an arrow by an elastic member 11 such as a spring. The fixing roller 7 is given a force in the direction of the heating element 6 by the elastic member 10.

The belt-shaped intermediate transfer member 5 is configured so that the photosensitive member 1 is not heated by the heat of the heating member 6, and the belt-shaped intermediate transfer member 5 is cleaned (not shown) so that toner adheres to the photosensitive member 1. Not to be configured.

The heating element 6 is composed of a heating element 12, and the toner forming a toner image on the belt-shaped intermediate transfer member 5 is transferred to the recording material 8 by the heat from the heating element and is fixed.

FIG. 2 is a diagram showing a second embodiment to which the present invention can be applied.

A recording material 8 is supplied between a heating member 6 and a belt-like intermediate transfer member 5 stretched around a fixing roller 7 provided opposite to the heating member 6. The fixing roller 7 is pressed against the heating element 6 by the elastic member 10, and the heating is performed from the back surface of the transfer material 8.

FIG. 3 is a diagram showing a third embodiment to which the present invention can be applied.

A transfer roller 4A is provided as an intermediate transfer member instead of the belt-shaped intermediate transfer member 5, and a heating member 6 provided opposite to the transfer roller 4A is pressed by an elastic member 14 so that the toner transferred to the transfer roller 4A is transferred. The image is transferred to the recording material 8 supplied between the transfer roller 4A and the heating element 6 and is fixed.

By using a roller of the same material as the transfer belt, the transfer belt is replaced with a roller.
The heating is performed from the back surface of the recording material 8.

FIG. 4 is a diagram showing a fourth embodiment to which the present invention can be applied.

In this example, the toner image transferred from the photoreceptor 1 to the recording material 8 is supplied to a fixing unit. In this example, a belt 15 stretched over the heating body 6 is provided opposite to the heating body 6. A dot toner 13 which is a toner image transferred to the recording material 8 is supplied between the fixing roller 7 and the fixing roller 7 and heat-fixed. The belt 15 is preferably made of a thin heat-resistant resin film having a releasing property so that the toner does not adhere to the heating body 6.

FIG. 5 is a diagram showing a fifth embodiment to which the present invention can be applied.

The dot-shaped toner 13 on the recording material 8 is directly heated and fixed by the heating element 12 of the heating element 6, and the surface of the heating element 6 is coated with fluorine to prevent the toner from being offset after fixing. I do.

FIG. 6 is a diagram showing a sixth embodiment to which the present invention can be applied.

An embodiment in which a part of the fifth embodiment is changed,
The fixing is performed by heating from the back surface of the recording material 8.

FIG. 7 is a diagram showing the correspondence between the heating element 12 and the dot-like toner 13 in FIG.
A heating element 12 is provided, an intermediate transfer body 5 is provided behind the heating element 12, a dot-shaped toner 13 is provided next, a recording material 8 is provided, and finally a fixing roller (not shown).

The heating element 12 includes a large number of elements 12A for one line inside the heating element 6. The element 12A is about the same size as one dot of the toner image on the intermediate transfer member 5. In the figure, a black mark indicates that a toner image is formed.

An element 12A of the heating element 12 is provided corresponding to the dot toner transferred to the intermediate transfer member 5, and a recording material 8 is provided between the intermediate transfer member 5 and a fixing roller (not shown). Is supplied, and when the element 12A and the dot toner 13 overlap, the element 12A is heated and fixed. The heating element 6 only needs to have a heating range equal to or larger than the dot transferred to the recording material 8. In FIG. 7, the element 12A for one line is provided, but a plurality of lines may be provided. The size of the heating element 12 is the same as that of the dot toner 1.
It may have a size larger than 3, for example, (n dots) × (m dots), and may be configured to heat n × m dots at a time.

Next, a method of heating the heating element 6 will be described.

FIG. 8 is a block diagram showing the control of development and fixing.

A code signal sent from a personal computer or the like is taken in from the I / F circuit 22 and stored in the buffer memory 25.

The CPU 21 reads font data from the font memory 24 according to the code stored in the buffer memory 25 based on the program stored in the program memory 23 storing the program, and sends the font data to the LED drive circuit 26. The LED drive circuit 26 transfers data of a shift register (not shown) to a latch (not shown), drives the LED head 2 to drive the LED head 2 to turn on the LED, and exposes the photoconductor 1. Then, a latent image is formed on the photoconductor 1.

At this time, the CPU 21 starts counting time based on a signal from the timer 27.

In FIG. 1, the distance from the position exposed by the LED head to the transfer to the belt-shaped intermediate transfer member 5 is denoted by La, and the heat generated by the heating element 6 from the position to which the belt-shaped intermediate transfer member 5 is transferred. Assuming that the distance to the position of the body 12 is Lb and the speed of the photoconductor 1 and the belt-shaped intermediate transfer body 5 is V, the latent image formed by the exposure is developed and formed on the belt-shaped intermediate transfer body. The transferred element 12 of the heating element 6
The time Tx required to reach the position opposite to is Tx = (La
+ Lb) / V.

On the other hand, the heating element drive circuit 28 receives data read from the buffer memory 25 by the CPU 21 in accordance with a program stored in the program memory 23. The received data is transferred from a shift register (not shown) to a latch (not shown) and sent to a drive circuit of a heating element 12 formed on the heating element 6.

FIG. 9 is a drive circuit diagram.

In FIG. 9, when there is no input data, that is, when the data is "L", the output at the point a becomes "H". Then, b
The states at the point and the point c are as follows.
C36 turns ON. Then, the capacitor C discharges and c
The point becomes “L”, and the output of IC 35 becomes “H” when the input is “H”.
"H" at "L", and the input of the IC 34 is "H".
And "H", and the output becomes "L". IC36 is OFF
, The capacitor C starts charging, and at the point c,
H ", the input of the IC 35 becomes" H "and" L ", and the output becomes" H ".The input of the IC 34 becomes" H "and" H ".
The output becomes "L" at "H", and the point b is stabilized at "L".
Then, the input of the IC 39 becomes “H” and “H”, and the output Dout becomes “L”.

Next, when Din changes from "L" to "H" due to data input, first, the output of the IC 33 becomes "L".
fall into. At that time, the input of the IC 32 becomes “L” and “H”, the output becomes “H”, and the input of the IC 31 becomes “H” and “H”.
H ", the output becomes" L ", and the input of the IC 33 becomes" H "and" L ", and the output becomes" H ". Then, a very short pulse of negative logic is issued.
When the point becomes “H”, the input of the IC 32 becomes “L” and “H”.
When Din falls to "L", the state returns to the initial state and waits for the rise of Din.

As for the IC 34, when the point a falls to "L", the point b becomes "H". When point b becomes "H", IC
The input of 39 becomes "H" and "L", and Dout becomes "H". When the IC 36 is turned on, the electric charge accumulated in the capacitor C is discharged, and the potential at the point c immediately drops. At the input end of the IC 35, when it is determined to be "L" lower than the threshold, the output of the IC 35 becomes "H".
Becomes At that time, the point a is already “H”, the output of the IC 34 is “L”, and the IC 36 is turned off.
, And charging of the capacitor C starts. At this time IC39
Become "L" and "H", and Dout remains "H".

Further, electric charge is accumulated in the capacitor C, and IC3
When the "H" threshold value of 8 is exceeded, Dout falls to "L", and the IC 35 also returns to the initial state.

If data arrives at Din before Dout does not become "H", that is, when the charge is not completely accumulated in the capacitor C, the IC3 is turned on in the same manner as described above.
6 turns ON, and discharges the capacitor C again. This extends the “H” period of Dout.

The heating element 12 is driven by the output of the drive circuit.
Rises to the temperature required for fixing. Assuming that the time required for the heating element 12 to rise to the temperature required for fixing is Ta,
The CPU 21 sets the heating element drive circuit 2 to Tx-Ta,
By sending the data to the dot 8, the dot toner 13 that has come to a position facing the element 12A can be heated and fixed.

The relative position between the dot-shaped toner 13 and the heating element 12 of the heating element 6 after a lapse of the time Tx from the formation of the latent image on the photosensitive element 1 is not necessarily completely eliminated. If they do not match, there are causes, for example, errors in the drive system, errors in assembly, errors in part processing, and the like. The time when the dot-shaped toner 13 and the heating element 12 face each other is Tx ± ΔTx
That is, when there is a shift of ΔTx, for example, Tx−Δ
When the dot toner 13 and the heating element 12 face each other at Tx, the CPU 21 monitors the timer 27, and when the time Tx−ΔTx−Ta elapses, the heating element driving circuit 28
To start heating the element 12A of the heating element 12 corresponding to the dot-shaped toner 13.

Only when the dot-shaped toner 13 of the image transferred in this way is present, the dot-shaped toner 13 is heated and fixed when it comes to a position facing the element 12A of the heating element 12 or in the vicinity thereof.

Note that the position of the dot-shaped toner 13 is
When the driving motor is a pulse motor, it rotates in synchronization with the pulse of the pulse motor, so that the timing and time of the heating element can be easily set.

FIG. 10 is a diagram provided with a line sensor.

When the dot-shaped toner 13 on the belt-shaped intermediate transfer member 5 approaches the heating element 12 of the heating element 6, the heating element 1
Based on the signal from the line sensor 18 provided in parallel with 2, the time until heat generation is calculated, or
Alternatively, heat fixing can be performed in the same manner as described above with reference to the time calculated in advance and stored in the table of the memory 23. At this time, the position of the line sensor 18 may be anywhere, but the accuracy of the control can be increased as the line sensor 18 is closer to the heating element, and there is less wasteful heat generation.

In FIG. 7, the positional relationship between the dot toner 13 of the toner image in the horizontal direction and the element 12A of the heating element 12 is 1: 1 by adjusting the positions of the LED head 2 and the heating element 6. It can be adjusted and matched accordingly. When this adjustment is difficult, by heating a plurality of elements 12A adjacent to the element 12A substantially corresponding to the dot-shaped toner 13 in the horizontal direction, it is possible to reliably heat and fix.

FIG. 11 shows that the photosensitive elements 1 of the LED head 2 corresponding to the elements 12A are provided by providing the elements 12A corresponding to a plurality of the dot toners 13.
FIG. 7 is a diagram when there is a write signal to the memory.

In FIG. 11, the data DL1 to data DL4 to the LED head corresponding to the data DE1 to the element 12A are 0% in the data DL1 and DL2.
In this case, the data DL3 and the data DL4 are 0. Since there is 1 in the data DL1 to DL4 to the LED head, the data DE1 to the element 12A is 1.

In the data DL5 to DL8 to the LED head corresponding to the data DE2 to the element 12A, the data DL5 is 1 and the data DL6 to DL8 are 0. Therefore, the data DE2 to the element 12A becomes 1. Since the data DLn to data DLn + 3 to the LED head are all 0, the data DEm to the element 12A is set to 0.

FIG. 12 is a view in which a plurality of rows of heating elements are provided. An example in the case where the dot-shaped toner 13 having the toner image transferred to the recording material 8 in the direction of the arrow in FIG. The heating element 6 is provided with a heating element 121, a heating element 122, and a heating element 123. When the dot toner 13 on the recording material 8 supplied in the direction of the arrow comes to a position facing the heating element 121, the heating element 121 generates heat and the dot toner 13 on the recording material 8 is preheated. This preheat is to fix the toner to the recording material 8 with less heating.
Preheating is performed by providing a heating element 121 at a temperature lower than the temperature at which the toner melts.

Next, when the dot-shaped toner 13 comes to a position facing the heating element 122, the heating element 122 generates heat.
The heating temperature of the heating element 122 at this time is set to a temperature at which the toner melts, but the amount of heat generated is not sufficient for the preheated dot-shaped toner 13 to be melted and fixed.

Next, when the dot-shaped toner 13 comes to a position facing the heating element 123, the heating element 123 generates heat.
At this time, the heating temperature of the heating element 123 is set to a temperature at which the toner is melted, and the amount of heat generated is set to a sufficient amount of heat necessary for fixing when the amount of heat applied by the heating element 121 and the heating element 122 is added. . In this way, the time Ta required to raise the temperature of the heating element 12 to a temperature required for fixing the dot toner 13 can be shortened, and the heat capacity of the heating element 12 per line can be reduced. . Therefore, stable fixing can be performed at higher speed. The positions of the heating element 12 and the dot toner 13 can be controlled in the same manner as described above.

In this example, the heating element 12 is replaced by a heating element 121.
, The heating element 122 and the heating element 123 are provided in three lines.
The configuration is not limited to the line, but may be another configuration.

Further, if the heating of the heating element 12 is performed by pulse heating, more advanced control becomes possible by controlling the height and width of the pulse.

In the above example, the case where the sizes of the dot toner 13 and the element 12A are approximately 1: 1 or n: 1 has been described.
The same configuration can be applied when A is 1: n. In addition, a similar configuration may be adopted in which fixing may be performed at a lower heating temperature in combination with pressure fixing. Although the above example has been described as an example of a printer, the present invention can be applied to devices such as a digital PPC, a facsimile, and a word processor with a printer function. The light source of the exposure is not limited to the LED, but can be applied to a laser beam system, a liquid crystal system, and other similar systems.

[0058]

According to the present invention, a toner for forming an image on a recording material is selected, and heat is efficiently generated for fixing the toner. Therefore, heat generation for fixing is extremely small and effective. Will be Therefore, the thermal design of the entire apparatus, not only the area around the heating element, becomes extremely easy, and it is possible to reduce the space and parts for cooling. Even if a member made of a thin layer such as a belt or a film is used around the heating element, the durability of the belt or the film can be improved because less heat is applied.

Further, the capacity of the driving portion for driving the heating element can be reduced, and energy saving, cost reduction and size reduction can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment to which the present invention is applied.

FIG. 2 is a diagram showing a second embodiment to which the present invention is applied.

FIG. 3 is a diagram showing a third embodiment to which the present invention is applied.

FIG. 4 is a diagram showing a fourth embodiment to which the present invention is applied.

FIG. 5 is a diagram showing a fifth embodiment to which the present invention is applied.

FIG. 6 is a diagram showing a sixth embodiment to which the present invention is applied.

FIG. 7 is a diagram showing the correspondence between elements of a heating element and dot toner.

FIG. 8 is a block diagram illustrating control of development and fixing.

FIG. 9 is a diagram illustrating a drive circuit of a heating element drive circuit.

FIG. 10 is a diagram showing an embodiment provided with a line sensor.

FIG. 11 is a diagram showing correspondence of data to LED heads and elements.

FIG. 12 is a diagram showing an embodiment in which a plurality of rows of elements are provided.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 2 LED head 3 developing roller 4 transfer roller 4A transfer roller as intermediate transfer member 5 belt-shaped intermediate transfer member 6 heating element 7 fixing roller 8 recording material 9 tension roller 10 elastic member 11 elastic member 12 heating element 12A element 13 Dot toner 14 Elastic member 15 Belt 16 Belt drive roller 17 Transfer charger 21 CPU 22 I / F circuit 23 Program memory 24 Font memory 25 Buffer memory 26 LED drive circuit 27 Timer 28 Heater drive circuit DL Data to LED head DE element Data to

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 13/16 G03G 13/20 G03G 15/16 G03G 15/20

Claims (3)

(57) [Claims] 1. An image forming apparatus having a heating member for transferring a toner image formed on an image carrier to a recording material and fixing by heating, wherein the heating member moves in a direction in which the toner image moves on the recording material. The recording material is arranged in a plurality of rows and extends in the intersecting direction and is divided in the same direction, so that the recording material passes between the heating body and a pressing body for pressing the recording material against the heating body. The heating element is controlled such that a portion corresponding to a portion through which the toner image passes generates heat , and the heating elements in the plurality of rows firstly pass through the first portion through which the toner image passes.
A row heating element and a second row heating element through which the toner image passes next
And the first row heating element has a temperature at which the toner image melts.
An image forming apparatus having a lower heating temperature . 2. An image having a heating member for transferring a toner image formed on an image carrier to an intermediate transfer member, and thereafter re-transferring the toner image on the intermediate transfer member to a recording material and simultaneously fixing by heating. In the forming apparatus, the heating element is arranged in a plurality of rows in the moving direction of the toner image on the intermediate transfer body, extends in an intersecting direction and is divided in the same direction, and the heating element contacts the intermediate transfer body. The recording material is configured to pass between the intermediate transfer member and the heating member, and the heating member is controlled such that a portion corresponding to a portion through which the toner image passes generates heat. The body is initially the first through which the toner image passes.
A row heating element and a second row heating element through which the toner image passes next
And the first row heating element has a temperature at which the toner image melts.
An image forming apparatus having a lower heating temperature . 3. An exposure apparatus for projecting and exposing a document image directly on an image carrier.
Light means, comprising a detecting means for detecting the formed image,
The heating of the heating element is controlled from the output signal of the detecting means.
That or converts the image signal into an optical signal comprising an exposure means for exposing on an image carrier, according to claim 1 or claim 2 heating of the heating body from the image signal is being controlled The image forming apparatus as described in the above.