JPH04107541A - Image forming device - Google Patents

Abstract

PURPOSE:To accurately discriminate the front/rear of the recording paper by emitting the recording paper with light being spreading and discriminating the front/rear of the recording paper based on the received light quantity of the light reflected from the recording paper. CONSTITUTION:The light being emitted from a light emitting element 41 is through an optical path A and reflected with color developing paper 28 and light is received with a light receiving element 42 but even though the position of the color developing paper shifted from the normal position to the upper or under position a little, since the light emitted from the light emitting element 41 has an expansion, light is received with a light receiving element 42 by passing through between from the optical path B to the optical path L, depending upon the position of the color developing paper 28. According the light received quantity of the light receiving element 42 does not change so much with the shift of the color developing paper 28. Thus the front side or rear side of the recording paper is accurately discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus, and particularly to an image forming apparatus equipped with a discriminating means for accurately discriminating the front and back sides of recording paper.

[Prior Art] Conventionally, an image forming apparatus that uses a photosensitive pressure-sensitive sheet as a recording medium exposes image information on a document to a photosensitive recording medium (microcapsule paper), and then transfers the exposed photosensitive recording medium to light. It is pressed onto a recording paper (color developing paper), and an image is pressure developed on the recording paper. Note that the recording paper has a predetermined color developer coated only on one side (surface) of the base paper,
In order to determine whether the recording paper is front or back, a front/back detection sensor is provided on the recording paper conveyance path.

That is, as shown in FIG. 5(a), a light emitting element 70 consisting of a laser light source irradiates parallel light onto the surface of a recording paper 74, and a light sensor circuit having a light receiving element 72 receives reflected light from the recording paper 74. (not shown) reads the light, and based on the amount of received light, a control device (not shown) determines whether the surface of the recording paper 74 is front or back.

[Problems to be Solved by the Invention] However, in the above-mentioned image forming apparatus, the recording paper 7
4 is shifted upward as shown in FIG. Element 7
2, the amount of light received by the light receiving element 72 changes significantly.

Therefore, there is a problem in that the control device cannot accurately determine whether the recording paper 74 is front or back.

Therefore, the present invention has been made to solve the above-mentioned problems, and even if the top and bottom positions of the recording paper are blurred while the recording paper is being conveyed, it is possible to accurately determine the front and back sides of the recording paper. The purpose is to provide an image forming apparatus.

[Means for Solving the Problems] In order to achieve this object, the image forming apparatus of the present invention has the following features:
A photosensitive recording medium on which image information on a desired document has been exposed and a recording paper are conveyed along a predetermined path, and the photosensitive recording medium is pressure-developed onto the recording paper, and light having a predetermined spread is emitted. The recording paper includes a light-emitting element that emits light toward the recording paper, a light-receiving element that receives light reflected from the recording paper, and a determining means that determines whether the recording paper is front or back based on the amount of light received by the light-receiving element. .

[Function] In the image forming apparatus described above, the light emitting element emits light having a predetermined spread toward the recording paper when the recording paper is conveyed to a predetermined position.

The light reflected from the recording paper is then received by a light receiving element. Further, the determining means determines whether the surface of the recording paper is front or reverse based on the amount of light received by the light receiving element.

[Example] Hereinafter, an example embodying the present invention will be described with reference to FIGS. 1 to 4.

First, to explain the overall configuration of the image forming apparatus, as shown in FIG.
A photosensitive pressure sensitive paper 12 (hereinafter referred to as microcapsule paper) which is a photosensitive recording medium and a color developing paper (hereinafter referred to as microcapsule paper) which develops color by pressure development.
Recording paper) 28 is used. Microcapsule paper 12
Microcapsules are coated on the surface of the support, and the microcapsules contain dye precursors and the like that react with the color developer described below. A color developer is applied to the surface (one side only) of the support of the color developer paper 28, and develops color by reacting with the dye precursor. That is, an image is formed on the color developer paper 28 only when the surface of the color developer paper 28 and the surface of the microcapsule paper 12 are supplied in a state where they are in close contact with each other and are integrated. For details, see U.S. Patent No. 439920.
9, etc., and the explanation will be omitted here.

At the top of the copying machine 1, there is a document table glass 2 and a document table cover 3.
A desired original 4 is placed on the original platen glass 2.
is placed face down and the document table cover 3 is closed.

A halogen lamp 5a and a reflector 5b are provided below the document table glass 2 in the upper part of the copying machine 1.

A light source unit 5 equipped with a reflecting mirror 8 and the like is disposed so as to be movable back and forth along a shaft 13 extending parallel to the document table glass 2 . The light source section 5 irradiates light onto the document table glass 2 in a line in a direction perpendicular to the movement direction. The irradiated light passes through the transparent document platen glass 2 and is reflected downward by the document 4 placed thereon.

Further, a mirror portion 9 having reflective mirrors 9a and 9b is disposed below the document table glass 2 and is movable separately from the light source section 5, and the light reflected from the document 4 is transmitted through the reflective mirror 9. 8.9a and 9b are reflected in this order and guided in parallel to the moving direction of the light source section 5.

Further, a projection lens 7, which is usually fixed, and a filter 6 for adjusting the color tone of the copied image are arranged below the document platen glass 2, and the light reflected by the reflection mirror 9b passes through the projection lens. 7. The light projected by the lens 7 is reflected by reflection mirror groups 10a and 10b.

An exposure stage 11 for exposing the microcapsule paper 12 is disposed to the right of the reflective mirror 10b, and a reflective mirror 10c for switching the optical path is disposed between the reflective mirror 10b and the exposure stage 11. ing. Image information on the document 4 is formed on the microcapsule paper arranged along the exposure table 11.

Further, although the reflecting mirrors 10a and 10b are normally fixed, they are set appropriately when enlarging or reducing the size of the latent image formed on the microcapsule paper 12, and the optical path length is adjusted according to a change in the projection magnification m. It has a structure that allows it to be moved integrally in the axial direction of the shaft 13 in order to change the position.

On the other hand, a cartridge 15 is disposed in the center of the copying machine 1 and is removably attached to the machine body.
A long microcapsule paper 12 is housed in the cartridge 15 in a state where it is wound around the cartridge shaft 14. Then, with the cartridge 15 set in a predetermined position inside the machine, the microcapsule paper 12 is
The distal end portion of is pulled out toward the exposure table 11.

A feed roller 19 and a dancer roller 21 for tension adjustment are provided below the exposure table 11. A pressure developing device 22 including a large diameter roller 22a and a backup roller 22b is disposed to the right of the dancer roller 21. To the right of the pressure developing device 22, there is a microcapsule paper 12 that is tightly attached as will be described later.
A separation roller 23 for separating the microcapsule paper 12 and the color developer paper 28 is provided, and a take-up shaft 24 for fitting and holding the microcapsule paper 12 is provided between the separation roller 23 and the cartridge 15. ing. The microcapsule paper 2 coming out from the top of the cartridge 15 is guided by a tension roller 19 and passes above the exposure table 11, then passes through a dancer roller 21, a pressure developing device 22, and is further transferred to a separation roller 23. After being guided, it is wound up on the winding shaft 24.

Note that the unexposed microcapsule paper 12 after leaving the cartridge 15 is maintained in an unexposed state by the light shielding cover.

A paper feed cassette 29 containing developer paper 28 is installed below the pressure developing device 22 . A suction cup-type paper feeding mechanism 30 that sucks paper using negative pressure suction is arranged above the paper feeding cassette 29.
0, one by one is taken out. A feed guide 31d and a feed roller 31a are provided between the paper feeding mechanism 30 and the pressure developing device 22.

31b, 31C, front and back detection sensors 40 are provided, and the color developing paper 28 is fed by rollers 31a, 31b.

31c1 is conveyed by the feed guide 31d and carried into the pressure developing device 22. At this time, the color developing paper 28 passes under the front/back detection sensor 40.

Further, on the left side of the front/back detection sensor 40, a conveyance path 60 is provided.
A discharge passage 62 is provided which merges with the discharge passage.

When it is determined that the color developer paper 28 that has passed under the front/back detection sensor 40 is the back side, the color developer paper 28 is transferred from the branch 52 to the discharge path 62 by the feed roller 31c, and further to the paper discharge port 50 by the discharge roller 51. be discharged.

A heat fixing device 32 is disposed to the right of the pressure developing device 22, and a paper discharge tray 33 for storing the developer paper 28 on which an image is formed is disposed to the right of the heat fixing device 32. ing.

Furthermore, this copying machine has an autoloading function for automatically setting the microcapsule paper 12 on a predetermined transport path within the apparatus.

This is a function that automatically pulls out the leader film portion attached to the tip of the microcapsule paper 12 into the device, transports it inside the device, and winds it around the winding shaft 24. As a result, the microcapsule paper 12 following the leader film section 18 is also wound up on the winding shaft 24, and the setting into the apparatus is completed.

For this autoloading, the leader film section 1
8, a roller 19 and a cartridge 15.
A half-moon roller 17 is disposed between the two, and a separation chute 27 is rotatably attached to guide the winding shaft 24 to the winding shaft 24.

A winding guide 25 and a winding guide 26 are disposed around the winding shaft 24 for winding the leader film.

Next, the front/back discrimination sensor 40 will be explained.

FIG. 2 is a schematic cross-sectional view of the front/back discrimination sensor 40,
The light emitting element 41 and the light receiving element 42 are disposed in close contact with the optical path guide 46, facing each other with a fixed distance therebetween. The light emitting element 41 is composed of a light emitting diode that can emit a wide range of light. The incident angle of the light emitted from the light emitting element 41 to the color developing paper 28 is about 60 degrees, the spread (half value angle α) of the light emitted from the light emitting element 41 is about 13 degrees, and the angle of incidence of the light emitted from the light emitting element 41 to the color developing paper 28 is about 13 degrees. The optical path length l is set to be approximately 33 mm.

Further, a detection circuit as shown in FIG. 3 is arranged on the substrate 45. The detection circuit is a circuit for detecting the reflectance of the developer paper 28, and is composed of a light emitting element 41, a light receiving element 42, two amplifiers 43, a constant current circuit 44, and the like.

In FIG. 3, Vl"ef is a reference voltage for driving the light emitting element with a constant current, and the light emitting element 41 is driven with a constant current by this value. The light emitted from the light emitting element 41 is reflected by the color developing paper 28. and reaches the light receiving element 42.

Then, it is amplified by an amplifier 43 and outputted as V Out. The output V out is input to a CPU (not shown) equipped with an A/D converter, and based on the value, it is determined whether the surface of the color developing paper 28 is front or back.

Next, the operation of this copying machine will be explained.

When the cartridge 15 is set in the copying machine 1, autoloading starts. Then, the half-moon roller 17 rotates once to several times in the conveyance direction only at the start of autoloading, and feeds the leader film section 18 to the roller 20. Thereafter, the half-moon roller 17 stops, and subsequent conveyance is performed by driving the roller 20. At this time, the take-up guide 25, the take-up guide 26, and the separation chute 27 have been rotated to the positions indicated by the dashed line.

Then, when the auto-loading for winding the microcapsule paper 12 around the winding shaft 24 is completed, the leader film part 18 attached to the tip of the microcapsule paper 12 is moved to the winding guide 25, the winding guide 26, and the separation chute 2.
7 returns to the position shown by the solid line and becomes ready for copying.

Next, when the copy start key is operated, the reflection mirror 8 and the halogen lamp 5 are moved to the microcapsule paper unit 2.
When the conveyance speed is ■ and the projection magnification is m, the moving speed V
/ m, and the reflecting mirrors 9a and 9b move at a speed of ■
Move at /2m.

The conveyance speed of the microcapsule paper 12 is determined by the mirror group 89a,
Since the moving speed of the document 9b is synchronized as described above, latent images of predetermined lines of the document 4 are sequentially formed on the microcapsule paper 12 as it passes through the exposure stage 11. Note that the predetermined speed ratio is predetermined based on the setting of the magnification.

The microcapsule paper 12 on which the latent image has been formed is transported,
The topmost color developing paper 28 of the paper feed cassette 29 is fed to the paper feed mechanism 30.
．． It is conveyed by feed rollers 31a, 31b, 310, etc. Then, the color developing paper 28 is connected to the front/back detection sensor 40.
When passing under the microcapsule paper 12, the reflectance of the color developer paper 28 is read by the detection circuit shown in FIG. Determine whether it is on the back side or on the back side.

At this time, the light emitted from the light emitting element 41 passes through the optical path A as shown in FIG. Even if the light is shifted slightly up and down from the position of
Depending on the position of , the light passes between optical path B and optical path C and is received by the light receiving element 42 . Therefore, the amount of light received by the light receiving element 42 does not change significantly due to the shift of the color developing paper 28.

In this way, if it is determined that the surface or surface of the color developer paper 28 is in contact with the microcapsule paper 12, the pressure developing device 22, the surface of the microcapsules on which the latent image of the microcapsule paper 12 is formed and the developer coated surface of the color developer paper 28 are brought into contact with each other on the inside, and are integrated into the large diameter roller 22a and the backup roller 22b.
Pressure is applied between the two. This pressure destroys the unexposed microcapsule paper 12 and forms an image on the developer paper 28.

The microcapsule paper 12 and the color developer paper 28 that have come out of the pressure developing device 22 are separated by the separation roller 23, and then the color development of the color developer paper 28 is promoted by the heat roller 32a of the heat fixing device 32 to form an image. After that, the paper ejection roller 32b
The paper is carried out to the paper discharge tray 33 by the paper discharge tray 33. Note that the separated microcapsule paper 12 is wound up on a winding shaft 24 via a separation roller 23e.

On the other hand, if it is determined that the color developer paper 28 that is in contact with the microcapsule paper 12 is the back side, the color developer paper 28 that has passed through the branch 52
8 is connected to the discharge path 6 from the branch 52 by the feed roller 31c.
Transferred to 2. Then, the color developing paper 28 is transferred to the discharge roller 5.
1, the paper is discharged from the discharge path 62 to the paper discharge port 50.

As described above, in the image forming apparatus of this embodiment, since the light emitted from the light emitting element 41 has a predetermined spread, even if the position of the color developer paper 28 is shifted vertically, the color developer paper 28
It is possible to accurately determine the front and back sides of 8. Therefore, it is possible to prevent wasteful work in which the developer paper 28 is fed upside down and the desired image is not formed.
This can prevent the paper from adhering to the paper and causing paper jams or malfunctions of the main unit.

[Effects of the Invention] As described in detail above, according to the present invention, even if the top and bottom of the recording paper are blurred, the control device can accurately determine the front and back sides of the recording paper. This can prevent wasteful work in which the recording paper is fed with its front and back sides reversed and the desired image is not formed. Also,
Paper jams and malfunctions of the main unit can also be prevented.

[Brief explanation of the drawing]

Fig. 1 is a side view of a copying machine showing an embodiment of the present invention, Fig. 2 is a schematic sectional view of a front/back discrimination sensor, Fig. 3 is a detection circuit, and Fig. 4 is a diagram showing the position of the developing paper in the front/back discrimination sensor section. FIGS. 5(a) and 5(b) are schematic diagrams showing the optical path depending on the position of the color developing paper in the conventional front/back discrimination sensor section. In the figure, 1 is a light and pressure sensitive copying machine, 12 is a light and pressure sensitive paper, 28 is a color developer paper, 40 is a front/back detection sensor, 41 is a light emitting element, 42
is a light receiving element. 821m Figure 4 @ Figure 5 (a) (b)

Claims (1)

[Scope of Claims] 1. In an image forming apparatus that conveys a photosensitive recording medium and a recording sheet onto which image information on a desired document has been exposed, to a predetermined path, and develops the photosensitive recording medium onto the recording sheet under pressure. , a light-emitting element that emits light with a predetermined spread toward the recording paper; a light-receiving element that receives light reflected from the recording paper; and determining whether the recording paper is front or back based on the amount of light received by the light-receiving element. What is claimed is: 1. An image forming apparatus comprising: a determining means for determining an image.