JP2569482B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus used in an optical printing apparatus such as a printer or a copying machine, and more particularly, to a photosensitive device in which a latent image is formed by exposure. The present invention relates to an image forming apparatus that develops a recording paper by applying pressure.

[Conventional technology]

The photosensitive pressure-sensitive recording paper is a recording medium in which microcapsules whose hardness changes according to the amount of exposure light and a color developer that develops a color by contact with the contents of the microcapsules are coated on a support. In order to form an image on the photosensitive pressure-sensitive recording paper, first, a latent image is formed by performing exposure according to the content of the document to be recorded, and then a hardness change is given by a pressure roll as a pressure unit. The microcapsules are destroyed and developed by reaction with a color developer to develop color.

Generally, an image forming apparatus using photosensitive pressure-sensitive recording paper performs development by passing between a pair of pressurizing units as described later with reference to FIG. In a conventional apparatus, the pressure applied to the pressure roll is configured to be constant by an adjustment made in advance in consideration of, for example, the thickness of the recording paper. Therefore, when the exposure amount for obtaining the latent image on the recording paper is constant, the recording paper exhibits a certain density,
It could not be easily adjusted.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus that develops a photosensitive pressure-sensitive recording sheet by pressing the recording sheet, in which the density of the developed image can be accurately and easily variably set so as to optimize the image density. It is to provide a device.

[Means for solving the problem]

An object of the present invention is to provide a density adjusting mechanism for generating a signal for optimally specifying the density of an image, and receiving at least a signal from the density adjusting mechanism to adjust at least one of the rotation speed and the pressing force of the pressing unit. This is achieved by providing a control device for variably setting.

〔Example〕

Prior to disclosing an embodiment according to the present invention, a conventional device will be outlined. FIG. 1 is a perspective view showing a main part of an image forming apparatus according to the prior art. In the figure, pressure rolls 1 and 2 as pressure portions of a pressure device are supported by upper and lower arms 3 and 4, and are adjusted by a pressing force adjusting mechanism 5 and a compression spring 6. The recording paper 7 on which a latent image is formed by being optically processed in a latent image forming apparatus (not shown) passes between the two pressure rolls 1 and 2 rotating as shown by an arrow 8 as shown by a white arrow 9. During this time, the film is developed by applying a predetermined pressure, and a visible image appears.

FIG. 2 is a characteristic curve showing the relationship between the pressure (horizontal axis) of the photosensitive pressure-sensitive recording paper and the color density (vertical axis). In this graph, the exposure amount and the pressurization time are recorded as being constant. In general, the diameter of the applied microcapsule on the photosensitive pressure-sensitive recording paper, the capsule hardness when curing is saturated,
Although it changes depending on the exposure amount, pressurization time and the like, the tendency is almost the same. For example, the slope α of the straight line portion at the center of the curve
Becomes smaller as the microcapsule hardness is increased.
The color density can be arbitrarily set by changing one or both of the pressing force and the pressurizing time using this linear portion.

FIG. 3 shows an embodiment of the image forming apparatus according to the present invention, in which both pressure rolls 11 and 12, upper and lower arms 13 and 14 are shown.
Is the same as the conventional device. The pressure roll 11 is supported at both ends by bearings on an upper arm 13 via bearings, and the pressure roll 12 is also supported by a lower arm.
These upper and lower arms 13 and 14 are configured to be rotatable at a point A at the tip thereof.

The pressing force of the pressure rolls 11 and 12 is
This is performed by a pressure adjusting mechanism at the rear end of the motor. This pressure adjustment mechanism is constituted by a bolt 16 and a spring 16 whose length is limited by a spring holding nut 20. When the compression state of the spring 16 changes, the tightening state of the rear ends of the upper and lower arms 13 and 14 changes with the point A at the front end as a fulcrum. As a result, the pressure applied to the photosensitive pressure-sensitive recording paper 17 changes.

In the image forming apparatus according to the present invention, the pressure roll
It has an additional mechanism for changing the pressing force of 11 and 12. This mechanism has a motor 21, a driving gear 22, and a driven gear 23 connected to the bolt 15, and is configured to rotate the bolt 15. This motor is conveniently a stepper motor. A first controller 24 for generating a suitable pulse output is connected to the stepping motor 21 and gives an instruction of forward rotation or reverse rotation to the motor. A signal according to the setting of the density adjusting mechanism 25 is input to this controller, and a corresponding output is given to the motor 21. As a result, a pressing force according to the compression state of the spring 16 is applied between the upper and lower arms 13 and 14, and the pressing force on the photosensitive pressure-sensitive recording paper 17 can be freely changed at any time before and after development.

Further, the image forming apparatus according to the present invention includes a density adjusting mechanism 25.
It is more convenient to provide a second controller 26 that can arbitrarily change the rotation speed of the pressure roller driving motor (not shown). By using either the rotation speed control and the pressure control described above alone or simultaneously, it is possible to adjust the concentration advantageously and appropriately.

〔The invention's effect〕

According to the present invention, the density of an image to be developed can be variably set accurately and easily so as to optimize the image density.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an image forming apparatus according to the prior art, FIG. 2 is an example of a pressure-color density characteristic curve of photosensitive pressure-sensitive recording paper, FIG. 3 is an image forming apparatus according to the present invention [Description of References] 11 ... Pressure roll 12 ... Pressure roll 13 ... Upper arm 14 ... Bottom arm 15 ... Bolt 16 ... Spring 17 ... Recording paper 20 Nut 21 Step motor 22 Drive gear 23 Driven gear 24 First controller 25 Density adjustment mechanism 26 Second controller

Continuation of the front page (72) Inventor Atsushi Sakai 9-35, Hottadori, Mizuho-ku, Nagoya-shi Inside Brother Industries, Ltd. (56) References JP-A-57-179836 (JP, A) JP-A-62-209535 ( JP, A) JP 47-2759 (JP, B1)

Claims (1)

(57) [Claims] 1. An image forming apparatus comprising: a microcapsule having a hardness changed by exposure to light, and a photosensitive pressure-sensitive paper on which a latent image is formed by exposure is developed by a pressure unit to develop the latent image. A density adjusting mechanism for generating a signal for optimal designation, and a control device for variably setting at least one of the rotation speed and the pressing force of the pressurizing unit in response to the signal from the density adjusting mechanism. An image forming apparatus.