JPH05273727A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an image forming device which is small in size and inexpensive and whose image quality is stable by providing a cooling means for a pressure transfer device and installing a temperature sensor and a controller. CONSTITUTION:In this image forming device, a photosensitive transfer type heat developable material is used, and an exposing device, a heat developing device and the pressure transfer device 60 are installed, then the cooling fan 100 for the device 60 is provided. Furthermore, the device has the temperature sensor 102 for detecting the temperature of the pressuring part of the device 60, and the controller 103 for changing the cooling power of the fan 100 in accordance with output from the sensor 102. When the detected temperature by the sensor 102 exceeds a temperature value previously set, the controller 103 energizes the fan 100, and when it becomes below the upper limit value of the temperature, the controller 103 stops energizing the fan 100. Therefore, density change caused by the temperature rise of a pressure transfer roller at the time of continuously outputting many copies is prevented, and the device is made small in size and inexpensive and the high-quality image is stably outputted.

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 copying machine or a printer, which forms an image by using a photosensitive transfer type heat developing material.

[0002]

2. Description of the Related Art A wide variety of image forming methods and apparatuses are known, and a conventional example of an image forming apparatus using a photosensitive transfer type heat developing material is, for example, Japanese Patent Laid-Open No. 62-
No. 147461 can be mentioned. According to this publication, main mechanical parts such as an exposure part, a heat developing part, and a pressure transfer part are formed inside one constituent body in the apparatus, and image formation is performed in the following procedure.

First, a roll-shaped photosensitive transfer type heat-developable material is cut into a predetermined length and then imagewise exposed to form a latent image. Next, thermal development is performed with a heating roller. After that, the photosensitive member and the image receiving paper are superposed and pressure-transferred by the roller, and the photosensitive member is transferred to the photosensitive material discarding section by the separating device.
The image receiving paper is discharged to the tray via the fixing device.

[0004]

The above-described embodiment has an excellent feature that an image forming apparatus capable of outputting a high-quality image with a small size and a low price can be obtained, but at the same time, it has the following drawbacks. had. That is, when a large number of images are continuously output, the density of the entire image is increased, resulting in a dark image. In particular, it was difficult to say that stable and good image quality can be obtained by giving the impression that the density of the white part in the image is significantly increased and the image quality is significantly deteriorated.

The inventor has discovered that the above-mentioned drawbacks are due to the temperature rise of the pressure roller of the pressure transfer device. First, it was confirmed that the photosensitive member was heated to a high temperature in the heat development step immediately before reaching the pressure transfer step, and was still in a high temperature state at the time of contact with the pressure roller of the pressure transfer device. Therefore, it is considered that the pressure roller continues to receive heat from the photosensitive member during continuous multi-sheet output and the temperature rises. Now, the temperature of the photosensitive member in the pressure transfer step becomes almost equal to that of the pressure roller. In the photosensitive transfer type thermal development device, the temperature rise of the photosensitive member leads to a decrease in the viscosity of the transferred ink,
The density is increased by improving the permeability to the image receiving paper.

The present invention solves the above problems in view of such a situation, and an object thereof is to provide an image forming apparatus which is small in size and low in price and has stable image quality.

[0007]

An image forming apparatus of the present invention is characterized by using a photosensitive transfer type heat developing material and including a cooling means of a pressure transfer device.

Further, the image forming apparatus has a temperature sensor for detecting the temperature of a pressure portion of the pressure transfer device, and a control device for changing the cooling power of the cooling means according to the output of the temperature sensor. And

[0009]

EXAMPLES The image forming apparatus of the present invention will be described in detail below with reference to examples.

FIG. 1 is a front sectional view of a copying machine showing an embodiment of the present invention. First, the operation of the copying machine will be described.

A document 2 is placed on a document table 1 movably provided in the direction of arrow A in the figure, and light rays emitted from a red lamp 3, a green lamp 4 and a blue lamp 5 which are light sources are emitted from the document 2. And the reflected light from the original 2 is imaged on the photosensitive member 8 that moves on the exposure table 7 through the lens 6 to form a so-called scan exposure system.

A continuous sheet-shaped photosensitive member 8 delivered from a cartridge 20 containing an unexposed photosensitive member 8.
After being exposed on the exposure table 7 to form a latent image, it is heat-developed by the heat developing device 40 via the carrying roller 9. on the other hand,
The cut sheet-shaped transfer member 11 housed in the paper feed tray 10 is sent out by the paper feed device 12, and is superposed on the photosensitive member 8 in synchronization with the image area formed on the photosensitive member 8 so that the roller pressing system is used. Pressure transfer is performed by the pressure transfer device 60. The pressure unit of the pressure transfer device 60 is composed of three rollers, an upper roller 61, a middle roller 62, and a lower roller 63, and pressure transfer is performed between the upper roller 61 and the middle roller 62.

After this, the transfer member 11 is separated from the photosensitive member 8 by the separating roller 64 and is discharged to the paper discharge tray 14 through the conveying roller 13. The photosensitive member 8 is pinched to promote the conveyance and separation of the photosensitive member 8. It is wound around the winding shaft 21 via the roller 65.

Reference numeral 15 is a manual paper feed port, and 16 is a gas filter for removing gas generated in the machine.

Next, the cooling device of the pressure transfer device, which is a feature of the present invention, will be described. FIG. 2 is a front sectional view showing the arrangement of the cooling device of the pressure transfer device 60 of the image forming apparatus of FIG. Approximately 12
The photosensitive member 8 heated to about 0 ° C. to 180 ° C. first comes into contact with the upper roller 61. Meanwhile, the middle roller 6
Reference numeral 2 denotes a pressurizing portion, which faces the photosensitive member 8 via the transfer member 11 sent from a sheet feeding device (not shown). Therefore,
In the roller structure of this embodiment, the temperature of the photosensitive member 8 is almost the same as that of the upper roller 61, and the transfer member 11 is insulated to some extent. It is sufficient to cool only 61. The lower roller 63 is for making the pressure distribution in the width direction uniform, and may have a drum shape, a so-called crown shape, or to contact the middle roller 62 at two or several points at appropriate positions. May be

The cooling fan 100 is installed in the duct 101 and is energized to generate cooling air in the direction of the arrow in the figure. The duct 101 is provided so that the air near the outside air temperature always flows in a certain position and in a certain direction, and it is considered that high temperature air near the thermal developing device is not taken in, and intake and exhaust are separated. ..

With the above structure, the cooling fan 100 has a static pressure of 3
When continuous copying was carried out by energizing so that the flow rate was mmH2O and the air volume was 0.3 cubic meters / minute, the temperature of the upper roller 61 hardly increased, and a stable quality image with almost no density fluctuation was obtained from the start of continuous copying. Was given.

Next, a second embodiment of the present invention will be described. FIG. 3 is a front sectional view showing a cooling device of the pressure transfer device 60 of this embodiment. In this embodiment, the temperature sensor 102 and the temperature sensor 1 for detecting the temperature of the upper roller 61 are added to the embodiment of FIG.
A control device 103 for varying the cooling power of the cooling fan 100 according to the detected temperature of 02 is added. Other configurations are similar to those of the embodiment shown in FIG. The temperature sensor 102 is a thermistor covered with a heat-resistant film, and is fixed to a frame of an apparatus body (not shown),
It is in slidable contact with the upper roller 61. Control device 1
03 is configured to energize the cooling fan 100 when the temperature detected by the temperature sensor 102 exceeds a preset temperature upper limit value, and to stop energizing the cooling fan 100 when the temperature falls below the temperature upper limit value.

In the above-mentioned embodiment shown in FIG. 2, when the cooling capacity of the cooling fan 100 is increased, the temperature of the upper roller may be lowered more than necessary, and conversely the density may be lowered. However, in this embodiment, since the cooling power is changed according to the temperature of the upper roller 61, a more stable image having no density fluctuation can be obtained.

Next, a third embodiment of the present invention will be described. FIG. 4 is a front sectional view showing the cooling device of the pressure transfer device 60 of this embodiment. In this embodiment, a halogen lamp heater 104 for heating the inside of the pipe-shaped upper roller 161 is added to the embodiment of FIG. The other structure is the same as that of the embodiment shown in FIG. In this embodiment, the present invention is applied to an image forming apparatus using a heat and pressure type pressure transfer device disclosed in JP-A-62-232653. In the above-mentioned conventional example, the transfer pressure is lowered by utilizing the fact that the density increases when the temperature of the upper roller rises, and the size and weight of the apparatus are reduced. This is because if only the heating device is provided, the upper roller 161 is heated by the heat from the photosensitive member 8.
This is because when the temperature becomes higher than the target temperature, the temperature cannot be lowered rapidly and an image with stable density cannot be obtained. In the present embodiment, the control device 105 is configured to energize the cooling fan 100 when the temperature of the upper roller 161 detected by the temperature sensor 102 is higher than the target temperature, and to energize the halogen lamp heater 104 when the temperature is lower than the target temperature. Therefore, the deviation from the target temperature is quickly eliminated.

In the present embodiment, a copying machine has been described as an example, but the present invention is not limited to this, and it is needless to say that the present invention can be applied to all image forming apparatuses such as printers, facsimiles, and electronic cameras.

[0022]

As described above, according to the image forming apparatus of the present invention, the image forming apparatus using the photosensitive transfer type heat developing material is provided with the cooling means of the pressure transfer apparatus,
Further, by having a temperature sensor that detects the temperature of the pressure portion of the pressure transfer device and a control device that changes the cooling power of the cooling means according to the output of the temperature sensor, pressure transfer at the time of continuous multiple-sheet output There is an effect that it is possible to provide a small-sized, low-priced image forming apparatus capable of stably outputting a high-quality image because it is possible to prevent a density change due to a temperature rise of the roller.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention.

FIG. 2 is a front sectional view showing a first embodiment of a cooling device for a pressure transfer device according to the present invention.

FIG. 3 is a front sectional view showing a second embodiment of the cooling device for the pressure transfer device of the present invention.

FIG. 4 is a front sectional view showing a third embodiment of the cooling device for the pressure transfer device of the present invention.

[Explanation of symbols]

 1 Original Plate 2 Original 3 Red Lamp 4 Green Lamp 5 Blue Lamp 6 Lens 7 Exposure Stand 8 Photosensitive Member 9, 13 Conveying Roller 10 Paper Tray 11 Transfer Member 12 Paper Feeding Device 14 Paper Ejection Tray 15 Manual Paper Feeding Port 16 Gas Filter 20 Cartridge 21 Winding Shaft 40 Thermal Development Device 60 Pressure Transfer Device 61, 161 Upper Roller 62 Middle Roller 63 Lower Roller 64 Separation Roller 65 Pinch Roller 100 Cooling Fan 101 Duct 102 Temperature Sensor 103 Control Unit 104 Halogen Lamp Heater

Claims (2)

[Claims] 1. An exposure device that exposes the photosensitive member, and a heat developing device that heats the photosensitive member, using a photosensitive member having on a support microcapsules in which at least a photosensitive material and a coloring material are encapsulated. An image forming apparatus comprising: a pressure transfer device that pressurizes the photosensitive member and the transfer member in an overlapping manner, and includes a cooling unit of the pressure transfer device. 2. The image forming apparatus includes a temperature sensor that detects a temperature of a pressure portion of the pressure transfer device, and a controller that changes a cooling power of the cooling unit according to an output of the temperature sensor. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.