JPH03212660A - Image forming device - Google Patents

Abstract

PURPOSE:To make a recording medium highly resistant regardless of ambient humidity and to efficiently perform high-quality printing by providing a means for heating the recording medium at the time of forming an electrostatic latent image. CONSTITUTION:A photoconductive film 1c on the surface of a photosensitive body 1 is uniformly electrostatically charged by an electrostatic charger 6. At the same time, the recording medium 100 conveyed by a recording medium conveying means 3 is heated by a heating means 21 so as to vaporize water content, and the surface of the recording medium 100 is made highly resistant. The recording medium 100 conveyed by the conveying means 3 is superposed on the photoconductive film 1c and charges 9 on the surface of the film 1c are held between the recording medium 100 and the film 1c. The recording medium 100 is conveyed to an exposing part. In the exposing part, the photosensitive body 1 is exposed by an optical image exposing means 4 from a transparent substrate 1a side and the charges 9 between the photoconductive film 1c and the recording medium 100 are selectively removed. Thus, the electrostatic latent image is formed on the recording medium 100. Then, the electrostatic latent image is developed by a developing means 5.

Description

[Detailed Description of the Invention] [Summary] Regarding an image forming apparatus that uses a photoreceptor to form an image on a recording medium such as recording paper, it is possible to efficiently perform high-quality printing regardless of changes in ambient humidity. For the purpose of this, after the surface of a photoreceptor in which a transparent conductive film and a photoconductive film are laminated on a transparent substrate is charged by a charging means, the charged photoconductive film is transported by a recording medium transport means. The photoconductive film and the recording medium are overlapped to hold the charge on the surface of the photoconductive film between the recording medium and the transparent substrate side of the photoreceptor is exposed by a photoimage exposure means to expose the photoconductive film and the recording medium. In an image forming apparatus that selectively removes charges between a medium and a medium to form an electrostatic latent image, and develops the electrostatic latent image by a developing means, the recording medium conveyed by the recording medium conveying means at least The structure includes a heating means for heating during formation of an electrostatic latent image.

[Industrial application field]

The present invention relates to an image forming apparatus that forms an image on a recording medium such as recording paper using a photoreceptor.

Image forming methods that use photoreceptors to form images on recording media are laser printers and facsimiles.

Used in devices such as copying machines. This image forming method is required to be able to form images stably over a long period of time.

[Conventional technology]

FIG. 3 is an explanatory diagram of this type of conventional image forming method.
1 is a photoreceptor, 2 is a charging means, 3 is a recording medium conveying means, 4
5 is a photoimage exposure means, and 5 is a developing means.

The photoreceptor 1 is formed by laminating a transparent conductive film 1b and a photoconductive film 1c on a transparent substrate la, and is movable in a fixed direction (to the right in the figure).

The charging means 2 includes a charger 6 facing the photoconductive layer 1c of the photoreceptor 1 at a predetermined position, and a charging power source 7 connected to the charger 6.

The recording medium transport means (recording paper transport belt) 3 includes a charger 6
The recording medium 100 is conveyed and superimposed on the photoconductive film 1c charged by the photoconductive film 1c. The conveyance direction and conveyance speed are the same as those of the photoreceptor 1.

The photoimage exposure means 4 is provided after the charger 6 and faces the transparent substrate 1a, and selectively removes the charge between the photoconductive film 1c and the recording medium 100 by exposing it to light from the transparent substrate 1a side.

The developing means (developing device) 5 includes a developing roller 8 and is arranged downstream of the optical image exposing means 4 so as to face the recording medium 100 .

When forming an image, first, as shown in FIG. 3(a),
The photoconductive film 1c on the surface of the photoreceptor 1 is uniformly charged by a charger 6.

Next, as shown in FIG. 3(b), the recording paper 100 is conveyed by the recording paper conveying means 3 and superimposed on the photoconductive film 1c, and the charge 9 on the surface of the photoconductive film 1c is transferred to the recording medium 100. hold in between.

Next, as shown in FIG. 3(c), the transparent substrate 1a side of the photoreceptor 1 is exposed to light by the optical image exposure means 4 to selectively remove the charges 9 between the photoconductive film 1c and the recording medium 100. to be removed. As a result, an electrostatic latent image is formed on the recording medium 100.

Next, this electrostatic latent image is developed by a developing roller 8 as shown in FIG. 3(d). In Figure 3(d), 1
0 is toner, and 11 is a developing bias power supply.

The developed toner image is then fixed by a fixing device (not shown).

[Problem to be solved by the invention]

In such a conventional image forming method, the recording medium 100 is superimposed on the charged photoconductive film 1c.
A light image is irradiated while a charge 9 is held between 0 and 0,
Since the latent image is formed by selectively removing the charges 9 between the recording medium 100 and the photoconductive film 1c, the latent image can be stably formed on the recording medium 100.

However, the relationship between the recording paper, which is a recording medium, and humidity is as shown in FIG. 4, and as the humidity increases, the moisture on the surface of the recording paper increases and the surface resistance decreases. When the surface resistance decreases, the transfer efficiency of the latent image to the recording paper decreases, or the charge 9 on the recording paper is discharged during the conveyance period from latent image formation to development, and the potential of the latent image decreases, resulting in a decrease in the potential of the latent image after development. There was a problem that the image quality deteriorated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can efficiently perform high-quality printing regardless of ambient humidity.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention, and in the figure, 21 is a heating means.

Note that the same reference numerals are used for members common to the conventional ones, and 2 indicates a photoreceptor formed by laminating a transparent conductive film 1b and a photoconductive film 1c on a transparent substrate 1c, and 2 indicates a charger 6 and a charging power source 7. 4 is a photoimage exposure means, and 5 is a developing means having a developing roller 8.

The heating means 21 heats the photoconductive film 1 by means of the recording medium transport means 3.
It is provided along the recording medium conveying means 3 to heat the recording medium 100 that is conveyed 9 and stacked on top of the recording medium 100 c.

[Function] When forming an image, first, as shown in FIG. 1(a),
The photoconductive film 1c on the surface of the photoreceptor 1 is uniformly charged by a charger 6. At the same time, the recording medium 100 conveyed by the recording medium conveying means 3 is heated by the heating means 21 to evaporate moisture and make the surface of the recording medium 100 high in resistance.

Next, as shown in FIG. 1(b), the recording medium conveying means 3
The recording medium 100 conveyed by
be held between. This recording medium 100 is conveyed to an exposure section.

In the exposure section, as shown in FIG. 1(c), the photoreceptor 1 is exposed to the transparent substrate 1a according to the image pattern by the optical image exposure means 4.
Exposure is performed from the side, and the charge 9 between the photoconductive film 1c and the recording medium 100 is selectively removed by the photoconductive effect of the photoconductive film 1c. As a result, an electrostatic latent image is formed on the recording medium 100.

Thereafter, the recording medium 100 is conveyed to a developing section as shown in FIG. to form a toner image.

This toner image is fixed by a fixing device in a fixing section (not shown).

〔Example〕

The invention will now be described in detail with reference to FIG.

FIG. 2 is a perspective view showing an outline of the structure of the image forming apparatus of this example. In the figure, 31 is a belt-shaped photoreceptor (corresponding to photoreceptor 1 in FIG. (equivalent to charger 6), 3
3 is a recording paper conveyance belt (corresponding to the recording medium conveyance means 3 in FIG. 1), and 34 is an LED head (light image exposure means 4 in FIG. 1).
), 35 is a developing device (corresponding to developing means 5 in Figure 1)
, 36 is a heater (corresponding to the heating means 21 in FIG. 1).

Further, 37 is a paper cassette for storing the recording paper 100;
8 is a pick roller.

The photoreceptor 31 is a belt-like member in which a transparent conductive film and a photoconductive film are laminated on a transparent substrate, and is passed around rollers 391 to 394 with the photoconductive film facing outside. Roller 39. ~
One of the rollers 394, for example a roller 394, is connected to a drive system, and driven by the roller 394, the photoreceptor 31 travels in the direction of the arrow.

The charger 32 includes a roller 39. ．． It is disposed facing the photoconductive film between 39□ and connected to a charging power source (not shown).

The recording paper conveyance belt 33 is connected to a drive roller 40. and the driven roller 40□ so that they run in the direction of the arrow, and the lower part is connected to the rollers 39, . 394 facing the photoreceptor 31.

The LED head 34 is mounted on a pulley 39. ．． 39. A large number of light emitting diodes are arranged facing each other on the transparent substrate side of the photoreceptor 31 between the photoreceptor 31 and arranged at a predetermined pitch in the width direction of the photoreceptor 31.

The developing device 35 is disposed between the roller 394 and the fixing roller 41 that is in pressure contact with the roller 40□, and is connected to the recording paper conveyance belt 3.
It faces the surface of 3.

The heater 36 is connected to the roller 40. ．． The recording paper conveyance belt 33 is disposed opposite to the back surface of the recording paper conveyance belt 33 between 40□.

42 is a static elimination lamp, and roller 39. ．． 39. It faces the photoconductive film of the photoreceptor 31 between the two.

The configuration overview of the image forming apparatus of this example is as described above.
Next, its effect will be explained.

The endless photoreceptor 31 circulates in the direction of the arrow, and the recording paper conveyance belt 33 also circulates in the direction of the arrow at the same speed. In the photoreceptor 31, the transparent conductive film is connected to the ground side, and the charger 32 is connected to the positive side of the charging power source 7, similarly to the photoreceptor 1 in FIG. 1(a). Therefore, the photoconductive film of the photoreceptor 31 is uniformly charged with a positive charge. In parallel with this movement, the recording paper 100 in the paper cassette 37 is fed out by the pink roller 38 and sent between the roller 401 and the opposing roller 43, and is sandwiched between the photoreceptor 31 and the recording paper conveyance belt 33. and reaches the LED head 34. During this time, as mentioned above in connection with FIG. 1(b),
The charge on the surface of the photoreceptor 31 continues to be held between the photoreceptor 31 and the recording paper conveyance belt 33, and the heater 36
Heat it to remove the moisture inside. Next, using the LED head 34, light is irradiated from the transparent substrate side of the photoreceptor 31 according to the image pattern, as described above with reference to FIG. 1(C). As a result, in the area irradiated with light, the electric charge between the photoreceptor 31 and the recording paper conveyance belt 33 is removed due to the photoconductive effect of the photoconductive film, and an electrostatic latent image is formed. This electrostatic latent image is transferred to the developer 35 as the recording paper 100 moves.
reach. In the developing device 35, as in FIG. 1(d), the recording paper conveyance belt 33 is set to the ground side, and the developing roller is charged to a positive potential with a developing bias power supply, and the electric field supplies toner to form a toner image. make. This toner image is
Thereafter, the image is fixed by a fixing roller 41 in a fixing section. On the other hand, the charge remaining on the photoreceptor 31 is removed by light irradiation from the charge eliminating lamp 42. Image formation is performed continuously by repeating this series of steps.

In this process, the recording paper is heated by a heater 36 when forming a latent image.
Since the recording paper is heated by the heat source, it is possible to make the recording paper high in resistance regardless of changes in ambient humidity, thereby increasing the efficiency of latent image formation and development. Furthermore, the potential of the latent image can be stably maintained while the recording paper is being conveyed, making it possible to realize high-quality printing.

In this example, since the heater 36 for heating the recording paper is arranged along the back side of the recording paper, the recording paper can be heated until the time of development, and more stable latent image formation can be realized.

〔Effect of the invention〕

As described above, according to the present invention, high-quality printing can be performed efficiently regardless of changes in ambient humidity.

[Brief explanation of drawings]

FIGS. 1(a) to (d) are diagrams explaining the principle of the present invention, FIG. 2 is a perspective view showing the outline of the structure of an image forming apparatus according to an embodiment of the present invention, and FIGS. 3(a) to (d) are Figure 4 is a diagram explaining the relationship between the surface resistance of recording paper and humidity. In the diagram, 1 is a photoreceptor, 1a is a transparent substrate, Ib is a transparent conductive film, and 1c is a photoconductive film. , 2 is a charging means, 3 is a recording medium conveyance means, 4 is a photoimage exposure means, 5 is a developing means, and 21 is a heating means.

Claims (1)

[Claims] A photoreceptor (1) consisting of a transparent conductive film (1b) and a photoconductive film (1c) laminated on a transparent substrate (1a) and moving in a fixed direction.
), a charging means (2) for charging the photoconductive film (1c) of the photoreceptor (1), and a recording medium is conveyed and superimposed on the charged photoconductive film (1c) to form the photoconductive film. (1c) a recording medium conveying means (3) for retaining the electric charge between the photoconductive film (1c) and the recording medium; An image forming apparatus comprising: a photoimage exposure means (4) that selectively removes charges to form an electrostatic latent image; and a developing means (5) that develops the formed electrostatic latent image. An image forming apparatus comprising a heating means for heating a recording medium conveyed by a medium conveying means (3) at least when an electrostatic latent image is formed.