JPH0416942A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain this device capable of surely executing thermal fixing by a simple control by performing the control so as to operate a driving means when the fact that temperature is set less than prescribed temperature is detected with a second or third temperature detecting means when a power source is applied to an image forming device and the device is set in a standby state. CONSTITUTION:When it is detected that the temperature of a pressurizing roller 56 is less than the prescribed temperature with the second temperature detecting means 86, or that of a belt 55 is less than the prescribed temperature with the third temperature detecting means 87 even when it is detected that the temperature of a heating roller 53 exceeds the prescribed temperature in a state where the power source is applied or the device is set in the standby state, the control is performed so as to set the temperature at the one exceeding the prescribed temperature by supplying heat from a heater 58 in advance to the part of the belt 55 easy to decrease the temperature or that of the pressurizing roller 56 by operating a driving motor 80 and changing a part in contact with the heating roller 53. Thereby, it is possible to prevent phenomenon such as temperature reduction at the part of the thermal fixing occurring when image formation work is started, which enables sufficiently stable thermal fixing work to be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an image forming apparatus using a photosensitive pressure-sensitive recording medium, and more particularly, to a control device for a heat fixing device for heat fixing a color developer sheet. This relates to temperature management control.

[Conventional technology]

In this type of image forming apparatus, a light-sensitive pressure-sensitive recording medium is used as a microcapsule sheet that encapsulates a dye precursor that develops color by reacting with a color developer and supports microcapsules whose mechanical breaking strength changes in response to light. The latent image formed by exposing the light-sensitive and pressure-sensitive recording medium is transferred by placing it on a color developer sheet carrying a color developer on its surface and applying pressure.

Next, as disclosed in the prior art Japanese Utility Model Application Publication No. 2-30947, the color developer sheet separated from the transferred microcapsule sheet is sent to a heat fixing device. A conveyor belt is wound around the roller, and a pressure roller is provided facing the heating roller,
Heat and pressure are applied to the surface of the color developer sheet between the conveyor belt around the heating roller and the pressure roller to develop a color image on the surface of the color developer sheet, and then give the surface of the color developer sheet an appropriate level of gloss. So-called heat fixing is performed.

[Invention or problem to be solved]

Conventionally, when power is turned on (ON) to an image forming apparatus,
In the heat fixing device, electricity is started to be applied to the heater of the heating roller, and a temperature detection means (temperature sensor) placed near the surface of the heating roller detects the temperature of the surface of the heating roller. Control was such that when the temperature required for heat fixing was reached, preparations for copying were completed.

However, even if the temperature of the conveyor belt part and the surface of the pressure roller in contact with the heating roller reaches a predetermined temperature, which is approximately the same as that of the heating roller part, pressure is applied at a position away from the contact part. The temperature of the rollers and conveyor belt is approximately the same as the temperature of the surrounding air.

If copying work is started in such a state, the following problems will occur.

That is, when the heat fixing operation in the copying operation is started, the conveyor belt and the pressure roller also rotate, and the lower temperature area contacts the heating roller that has reached the predetermined temperature and takes away the heat. The temperature of the roller rapidly drops below a predetermined temperature. Therefore, even if the lowered temperature is sensed and the heater section of the heating roller is energized to supply heat, there will be a time delay until the pressure roller or conveyor belt reaches a predetermined temperature. This may occur due to poor heat fixing. Particularly, there is a problem in that this defective accident becomes more noticeable during times when the ambient temperature is low, such as in the winter.

The present invention has been made to solve this problem, and an object of the present invention is to provide an apparatus that can perform reliable heat fixing with simple control.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a first temperature measuring means for detecting the temperature of the heating roller, a second temperature measuring means for detecting the temperature of the pressure roller, and a third temperature measuring means for detecting the temperature of the belt. and a temperature control means for controlling the amount of electricity supplied to the heat source to set the temperature of the heating roller to a predetermined value based on the detection result of the first temperature measuring means, the image forming apparatus comprising: When the second temperature measuring means or the third temperature measuring means detects that the temperature is below a predetermined temperature when the power is turned on to the apparatus and while the apparatus is waiting for operation, the driving means for driving the roller and the belt is actuated. It was controlled to

〔Example〕

Hereinafter, embodiments embodying the present invention will be described based on the drawings.

FIG. 1 shows a photosensitive and pressure-sensitive copying machine that implements the image forming apparatus of the present invention.

In the copying machine 20 of this embodiment, as shown in FIG. 1, photosensitive paper consisting of microcapsule paper 21 and color developer sheet 22 is used as a photosensitive and pressure sensitive recording medium.

In addition, the microcapsule paper 2 used in this example
Microcapsules are coated on the surface of 1, and the microcapsules contain dye precursors and the like that react with a color developer described later. The surface of the color developer sheet 22 is coated with a color developer, which develops color by reacting with a dye precursor.
It is described in the official gazette of , etc., and is omitted here.

A desired document 25 is placed face down on a document table glass 23 disposed at the upper part of the copying machine 20, and the upper part thereof is covered with a document table cover 24.

A halogen lamp 26 is provided below the document table glass 23.
a, a reflector 26b, a reflection mirror 27, etc., and a light source unit 26 or a shaft 28 installed parallel to the document table glass 23.
It is arranged so that it can be moved back and forth along.

The light from the light source unit 26 is irradiated in a line shape in a direction perpendicular to the moving direction toward the document table glass 23, and the irradiated light passes through the transparent document table glass 23 and is placed on the document table glass 23. The light is reflected downward by the scratched original 25.

The light reflected from the original is reflected in the order of the reflection mirror 27 in the light source section 26 and the reflection mirrors 29a and 29b in a mirror part 29 that is movable separately from the light source section 26, is guided so that it is parallel to the direction of movement.

A normally fixed projection lens 30 and a filter 3I for adjusting the color tone of the copied image are disposed below the document platen glass 23, and the light reflected by the reflection mirror 29b is directed to the projection lens 30. incident. The lens 30
The light projected by is reflected by reflection mirror groups 32a and 32b.

The reflection mirror groups 32a and 32b are arranged on the axis 2 in order to change the optical path length according to the change in the projection magnification m when enlarging or reducing the size of the latent image formed on the microcapsule paper 21.
8 in the axial direction.

An exposure table 33 for exposing the microcapsule paper 21 is arranged on the right side of the reflection mirror 32b, and a reflection mirror 32c for switching the optical path is arranged between the reflection mirror 32b and the exposure table 33. It's there. Image information on the original 25 is formed on the microcapsule paper 21 disposed along the exposure table 33 .

On the other hand, a removable cartridge 34 is disposed in the center of the copying machine 20, and the cartridge shaft 34 is disposed in the center of the copying machine 20.
A long length of microcapsule paper 21 in a state of being rolled up into 5 pieces is housed therein.

Further, this copying machine has an autoloading function for automatically setting the microcapsule paper 21 on a predetermined transport path within the machine.

Reference numeral 36 denotes a half-moon roller for drawing out the leader film portion attached to the tip of the microcapsule paper 21;
A tension roller 37 and a separation chute 39 for guiding the winding shaft 38 to the winding shaft 38 are rotatably attached. An upper winding guide 41a and a lower winding guide 41b are arranged around the winding shaft 38 for winding the leader film.

Microcapsule paper 2 coming out from the top of the cartridge 34
1 is guided by a tension roller 37 and passes above the exposure table 33, and then passes through a pressure developing device 42 that includes a feed roller 40a, a dancer roller 40b for tension adjustment, and a large diameter roller 42a and a backup roller 42b. The sheet passes through the sheet, is further guided to a separating roller 43, and then wound onto a winding shaft 38.

As a result, the microcapsule paper 21 following the leader film portion is also wound up on the winding shaft 38, and the setting in the apparatus is completed.

Note that the unexposed microcapsule paper 2I after leaving the cartridge 34 is maintained in an unexposed state by a light shielding cover or the like.

On the other hand, a paper feed cassette 4 provided below the pressure developing device 42
The developer sheets 22 stored in the color developer sheet 5 are taken out one by one by a suction cup-type paper feeding mechanism 46 that sucks the paper using negative pressure suction. Between the paper feeding mechanism 46 and the pressure developing device 42,
Feed roller 47a.

47b, 47c, and a feed guide 47d, and are carried into the pressure developing device 42.

In case 2, the microcapsule paper 2 is processed by the pressure developing device 42.
After transferring the latent image from the microcapsule paper 2 to the color developer sheet 22, the color developer sheet 22 is separated by a separation roller 43, and the color developer sheet 22 is transferred to the heat fixing device 4, which will be described later.
Sent to 4.

A heat fixing device 44 is disposed to the right of the pressure developing device 42, and a paper discharge tray 48 for storing the color developing notebook 22 on which an image has been formed is disposed to the right of the heat fixing device 44. It is set up.

The heat fixing device 44 fixes the color developing sheet 22 with the surface facing upward.
a pair of feed rollers 50 for conveying the material in the six directions of arrows;
50, a kite plate 52.52 disposed adjacent to the feed roller pair 50.50, and an endless belt 55 which is wound around and rotated between a heating roller 53 and a discharge roller 54 disposed between a pair of frames 51.51. and a pressure roller 56 that presses against the heating roller 53. Reference numeral 57 is a support plate that receives the color developing sheet 22.

A heater 58 is disposed inside the heating roller 53, and the developing sheet 22 is heated and pressurized between it and the pressure roller 56, and is separated at the discharge roller 54 side while being cooled as the belt 55 moves. do.

Numerals 59 and 59 are bearings for rotatably supporting both ends of the support shaft 60 of the heating roller 53 on the frame 51.51, and 61 and 61 are bearings for rotatably supporting both ends of the support shaft 62 of the discharge roller 54. The two bearings 61.
61 is a longitudinal guide groove 63 bored in the frame 51°51.
63 so as to move toward and away from the support shaft 60 of the heating roller 53 .

Reference numeral 64 applies an equal tensile force to both ends of the discharge roller 54 in the direction away from the heating roller 53;
The urging means 64 includes a pair of outer rings 65 and 65 that are rotatably fitted onto both ends of the support shaft of the discharge roller 54, and the amphiphilic ring. A pair of tension bodies 66 66 such as wires having one end attached to the tension bodies 65 , one biasing spring 67 such as a coil spring connecting the other ends of the pair of tension bodies 66 , 66 , and the pair of tension bodies 66 . Roller 68.6 guiding the middle part of .66
Each roller 68 is fixed in position by being attached to the frame 51 via a bracket 69.

Reference numeral 70 denotes a pressure adjustment driving means for the pressure roller 56, and a pivot shaft 7 rotatably mounted on the frame 51.51.
A spindle 74 of the pressure roller 56 is rotatably supported by an arm 72 fixed to one end of the swing arm 72 and a swing arm 73 fixed to the other end of the swing arm 73.
The eccentric cam 76 is always in contact with the circumferential surface of the swing arm 73, and the eccentric cam 76 is rotated by a step motor 79 via a pair of gears 77 and 78 to change and adjust the swing angle of the swing arm 73. Accordingly, the pressure force can be adjusted to be stronger or weaker.

Reference numeral 80 is a drive motor that drives the heating roller 53 and the heald 55, and above the heat fixing device 44,
In order to remove the smell of residue generated during the heat fixing,
A scum adsorption filter device 81 including a gas adsorption filter body (not shown) and an exhaust blower is provided in the chi sink 82, and the gas adsorption filter body is replaced when a certain amount of dregs is adsorbed.

Reference numeral 83 is a cooling fan for sucking out air from the optical system of the copying machine (2) to cool it.

Reference numeral 85 is a first temperature measuring means for detecting the surface temperature of the heating roller 53, and reference numeral 86 is a second temperature measuring means for detecting the surface temperature of the surface of the pressure roller 56 on the side remote from the heating roller 53. Temperature measuring means, reference numeral 87, is a third temperature measuring means for detecting the surface temperature of the belt 55 on the side away from the heating roller 53 (the side not affected by the heat of the heating roller 53), and these temperature measuring means Means 85, 86.87
Each consists of a thermistor, etc.

Reference numeral 88 inputs the detection results etc. from the three temperature measuring means 85, 86°78, and controls the heater 58 and the drive motor 80.
The central processing unit (CPU) 89 has a read-only memory (ROM) 90 and a read/write memory (
RAM) 91, and these read-only memories (RO
M) Control is executed according to the program stored in the subroutine 90, such as driving and stopping the drive motor 80, determining the amount of electricity to be applied to the heater 58, etc. according to the subroutine flowchart shown in FIG. Also, you can use readable and writable notes to set and change the conditions! Next, the operation of this copying machine and the control of the heat fixing device will be explained.

When the cart rerun 34 is set in the copying machine 1 and the leader film attached to the tip of the microcapsule paper 21 is wrapped around the winding shaft 38, the upper winding kite 25 and the lower winding kite 26
, the separation node 27 returns to the position shown by the solid line, and copying becomes possible.

When the power switch 92 in the copying machine 1 is turned on to turn on the power, the heater 58 starts to be energized.

Step 601 following the start and initialization of the subroutine in the flowchart (see Figure 6) is performed when the power is turned on or during standby (during the warm-up state after the power is turned on).
or in a preheated state to save power when not in use for a long period of time).
If so, a copying operation is executed in step 602.

When YES in step 601, the detection result of the first temperature measuring means 85 is read in step 603, and step 60
4, the surface temperature of the heating roller 53 reaches a predetermined temperature (for example, 1
30°C) or higher.

If no in step 604 (when the temperature of the heating roller 53 is low), the process returns to step 603 and step 603 is executed again.

The heater 58 continues to be energized until the temperature of the heating roller 53 reaches, for example, 130°C, and after reaching 130°C, on/off control of the energization is executed.

If YES in step 604 (when the temperature of the heating roller 53 is high), then in step 605 the detection result of the second temperature measuring means 86 is read, and in step 606 the pressure roller 56 is moved away from the heating port 53. It is determined whether the surface temperature of the location is below a predetermined temperature (for example, 115° C.).

If YES in step 606 (when the temperature of the pressure roller 56 is low), the drive motor 80 is turned on in step 607 to rotate the heating roller 53 and the pressure roller 56, and the contact point between the two is turned on. The temperature changes, and the locations with lower temperatures are brought into contact with the heating roller 53 and heat is applied thereto, and the process returns to before step 601.

When the answer in step 606 is no (when the temperature of the pressure roller 56 is high), in step 608, the third temperature measuring means 8
7 is read, and in step 609, the held 55
It is determined whether the surface temperature of a portion away from the heating roller 53 is lower than a predetermined temperature (for example, 110° C.).

If YES in step 609 (when the temperature of the belt 55 is low), the drive motor 80 is turned on in step 607 in the same manner as described above, and the heating roller 53 and pressure roller 55 are turned on.
6 is rotated to change the contact point between the two, heat is applied to the low temperature point of the pressure roller 56 in the same manner as described above, and the process is returned to before step 601.

If no in step 609 (when the temperature of the heald 55 is high), the process proceeds to step 601 to prohibit driving of the drive motor 80, and returns to the process before step 601.

In this way, not only the heating roller 53, but also both the pressure roller 56 and the heald 55, the temperature at a location away from the heating roller 53 that tends to be low generally becomes approximately the above-mentioned predetermined temperature. After this, the printer exits the waiting step and moves on to the copying operation described below.

Next, when the copy start key is operated, the reflecting mirror 27 and the halogen lamp 26a move at a moving speed of 1/m V, assuming that the transport speed of the microcapsule paper 21 is V and the projection magnification is m, and the reflecting mirror 29a, 29b moves at a moving speed of 1/2 mV.

The conveyance speed of the microcapsule paper 21 is determined by the mirror group 27.
Since the moving speeds of the document sheets 29 a and 29 b are synchronized as described above, latent images of predetermined lines of the original document 25 are sequentially formed on the microcapsule paper 21 as it passes through the exposure table 33 . Note that the above-mentioned predetermined speed ratio is determined in advance based on the setting of the magnification.

The pressure developing device 42 is supplied with the microcapsule paper 21 on which the latent image has been formed and the color developing sheet 22 in close contact with each other as one body, and the microcapsule surface on which the latent image on the microcapsule paper 21 has been formed and the surface of the microcapsules on which the latent image has been formed are The color developer coated surface of the color developer sheet 22 is in contact with the inner side and is sandwiched between the large diameter roller 42a and the backup roller 42b, and pressure is applied thereto. This pressure destroys the unexposed microcapsules and transfers the image onto the color developing sheet 22.

After the microcapsule paper 21 and the color developing sheet 22 that have come out of the pressure developing device 42 are separated by a separation roller 43,
The color developer sheet 22 is accelerated in color development by the heating roller 53 of the heat fixing device 44 to form an image, and is then transferred to the discharge roller 5.
The paper is delivered to the paper discharge tray 48 from the 4 side.

The passage surface of the color developer sheet 22 in the heat fixing device 44 may not be horizontal, but may be inclined or vertical, and may also be applied to a copying machine equipped with both a monochrome laser printer and a color image forming device. Needless to say, it is applicable.

[Action of the invention]

As described above, when the image forming apparatus is powered on or while the apparatus is on standby, the heating roller 53 is heated by the first temperature measuring means 85.
Even if it is detected that the temperature of the pressure roller 56 is above a predetermined temperature, the second temperature measuring means 86 detects that the pressure roller 56 is below the predetermined temperature, or the third temperature measuring means 87
When it is detected that the temperature of the heald 55 is below a predetermined temperature,
Pressure roller 56 and heating roller 53 in belt 55
Since the temperature at a position away from the contact point with the heating roller 53 is lower than the predetermined temperature, by operating the drive motor 80 and sequentially changing the contact point with the heating roller 53, the temperature of the heald 55 and Heat from a heater 58 is applied in advance to 56 locations of the pressure roller to control the temperature to a predetermined temperature or higher.

〔Effect of the invention〕

As described in detail above, according to the present invention, the drive motor of the heat fixing device is operated when the power of the image forming apparatus is turned on or while the image forming apparatus is on standby, and the heat from the heating roller is easily reduced. Since the heat can be transmitted to the pressure roller and heald and sufficiently preheated, the heat roller will not be deprived of heat by the pressure roller or belt when the heat fixing process starts, and the image forming process will be faster. This makes it possible to carry out a sufficiently stable heat fixing operation without causing the phenomenon of temperature drop at the heat fixing point at the start.

In addition, with this control device, by simply adding two temperature measuring means, one at the pressure convex and one at the belt point, the drive motor and heating heater that are necessary for the original function of the device can be used as is. Therefore, the structure does not become complicated and the increase in cost can be suppressed.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall configuration diagram of a copying machine, FIG. 2 is a perspective view of main parts of a heat fixing device, FIG. 3 is a plan view, and FIG. 4 is an IV diagram of FIG. 3. -IV sectional view, FIG. 5 is a block diagram of the control device, and FIG. 6 is a flowchart. 20... Copying machine, 21... Microcapsule paper, 2
2... Color developer sheet, 26... Light source unit, 42... Pressure developing device, 44... Heat fixing device, 45... Paper feed cassette, 48... Paper output tray, 51.51. ...Frame, 53...Heating roller, 55...Belt, 56.
... Pressure roller, 58 ... Heater, 70 ... Pressure adjustment drive means, 79 ... Step motor, 80 ... Drive motor, 85 ... First temperature measuring means, 86 ... No. 2 temperature measuring means, 87... third temperature measuring means, 88... control device, 89... central processing unit, 90... read only memory (ROM), 92... power switch. Agent Patent Attorney Tadashi Higashino Story Figure 4 Figure 3

Claims (1)

[Claims] (1) A belt wrapped around a heating roller equipped with an internal heat source and a discharge roller, and a color developing sheet onto which a latent image has been transferred from a photosensitive pressure sensitive recording medium are pressed toward the heating roller. A heat fixing device is constituted by a pressure roller and a driving means for driving these rollers and a belt, a first temperature measurement means for detecting the temperature of the heating roller, and a second temperature measurement means for detecting the temperature of the pressure roller. , comprising a third temperature measuring means for detecting the temperature of the belt, and a temperature controlling means for controlling the amount of electricity supplied to the heat source to set the temperature of the heating roller to a predetermined value based on the detection result of the first temperature measuring means. an image forming apparatus comprising: when the second temperature measuring means or the third temperature measuring means detects that the temperature is below a predetermined temperature when the power is turned on to the image forming apparatus and while the apparatus is on standby; An image forming apparatus characterized in that the driving means is controlled to operate.