JPH0489743A - Paper feed device in image forming device - Google Patents

Abstract

PURPOSE:To optimize sheet suction by judging the kind of sheets received in a cassette by a judging means to switch the sucking quantity data according to the kind, and controlling a negative pressure generating means on the basis of this data. CONSTITUTION:When the bar code of a sheet package received in a cassette is detected, the kind of sheets is judged by a judging means, and its signal is sent to a microcomputer. Various sucking quantity data according to kinds are stored in the computer, and the sucking quantity data according to the signal is taken out. When a sensor 73 is lowered to detect the sheet, the lowering of a rotating arm 72 is stopped, and it is rotated to bring a suction cup 71 installed to the arm 72 into contact with the sheet upper surface. A piston 55 is operated on the basis of the sucking quantity data, and the optimum sucking force according to the kind of sheet is worked on the suction cup 71 to suck the sheet, which is thus separated and supplied. Thus, the paper feed can be certainly performed regardless of the kind.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device for taking out paper from a paper feeding cassette in order to form an image of a document on paper in an image forming apparatus.

[Conventional technology]

Conventionally, light is irradiated from a light source onto an original placed on a platen glass, the reflected light is used to expose microcapsule paper as a photosensitive and pressure sensitive recording medium, and the microcapsule paper is combined with color developing paper as paper. An image forming apparatus is known that performs pressure development using a pressure developing device and forms an image of the original on this developer paper. The developer paper is stored in a paper feed cassette, and in order to prevent the paper surface of the developer paper from being damaged when taking out the stored developer paper to be transported toward the pressure developing device. It uses a suction cup.

[Problem to be solved by the invention]

By the way, as a result of improvements in sensitivity, etc. of the microcapsule paper proposed in Jikai No. 58''-88739, etc., different types of microcapsule paper coexist on the market. started to happen.

These microcapsule papers have different base film thicknesses, as well as differences in the amount and quality of applied microcapsules, the presence or absence of vapor-deposited aluminum film, and the thickness of that film. There are differences etc.

In response to these several types of microcapsule paper, color developer papers have been developed that differ in the thickness and quality of the base paper and in the amount and quality of the color developer applied.

Further, a color developing paper using PET as a base paper has been devised so that an output image can be projected on an OHP. Here, separation of the color developer paper is performed by balancing the suction force of the suction cup and the stiffness of the color developer paper. For example, if the base paper is PET, the negative pressure inside the suction cup must be increased, otherwise the developer paper will be stiff and the developer paper will separate from the suction cup when the separation operation is performed. Additionally, if the base paper is thin and the negative pressure inside the suction cup is too large, the developer paper has some air permeability and is weak, making it difficult to achieve reliable separation even with the separation operation. There will be no. Therefore, in this case, the negative pressure inside the suction cup must be reduced. The adjustment of the separation operation during the above paper feeding operation is done in addition to the magnitude of the negative pressure inside the suction cup.
This can also be done by changing the angle at which the developer paper is turned over during the separation operation.

As described above, if the type of color developing paper changes, the suction amount must be changed accordingly to ensure a reliable separation operation. For this purpose, a method of installing a suction amount changeover switch on the panel was considered, but this was not practical because it would require an increase in the number of switches and complicate the input procedure when there are many types of color developing paper. Therefore, there is always a risk that double feeding or paper feeding failure may occur due to incorrect selection of the suction amount.

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feeding device for an image forming apparatus in which the suction amount can be reliably changed depending on the type of color developing paper, and double feeding and paper feeding failures do not occur.

[Means to solve the problem]

In order to achieve such an object, the present invention includes a paper feed cassette storing paper, a suction cup for taking out the paper by suction from the paper feed cassette, and a suction cup for sucking the paper. A negative pressure generating means for generating negative pressure, a paper discrimination means for discriminating the type of paper stored in the paper feed cassette, and suction amount data according to the paper type, and suitable for the paper stored in the paper feed cassette. A suction amount data switching section that switches to suction amount data that has been selected, and a control section that controls driving of the negative pressure generating means based on the suction amount data that has been switched by the suction amount data switching section. be.

[Effect]

When the paper feed cassette containing the paper package is placed in the cassette holder, the paper type is determined by the paper discrimination means. The paper determining means outputs a signal to the microcomputer according to the type of paper, and the suction amount data is switched to the optimum suction amount data by the suction amount data switching section. A drive signal is output from the control section to the drive circuit based on the suction amount data. When a drive current is applied from the drive circuit to the negative pressure generating means based on the drive signal, the negative pressure generating means operates by a predetermined amount, and a negative pressure corresponding to the type of paper is generated in the suction cup. That is, when the base paper of the paper is thick and stiff, the negative pressure inside the suction cup is increased, and when the base paper of the polarized color paper is thin and weak, the negative pressure inside the suction cup is decreased.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings. 1 to 6 are diagrams showing a paper feeding device in an image forming apparatus according to the present invention. In FIG. 1, an original platen glass 2 and an original platen cover 3 are provided on the top plate of an image forming apparatus 1, and a desired original 4 is set face down on the original platen glass 2. Ru. A light source using a halogen lamp 5 or the like is disposed at the top of the image forming apparatus 1, and irradiates light in a line through a slit provided on the top surface of the device toward the document table glass 2. The light passes through the transparent original table glass 2 and is reflected from the original 4 placed thereon. The light reflected from the original 4 is directed by a group of reflective mirrors 8.9a and 9b, passes through a filter 6 for adjusting the color tone of the formed image, enters a projection lens 7, and enters a projection lens 7. The light projected by
The image is formed on a photosensitive and pressure sensitive recording medium (hereinafter referred to as microcapsule paper) 12 located along 1.

The movements of the reflecting mirrors 8.9a, 9b, lens 7, and halogen lamp 5 will be explained. If the conveying speed of the microcapsule paper 12 is V1 and the projection magnification is m, then the halogen lamp 5
and the moving speed of the mirror group of reflection mirror 8 is (1/m)XV
, reflective mirror 9a.

By setting the moving speed of 9b to (1/2 m) x V,
It becomes possible to expose the image on the original 4 onto the microcapsule paper 12. Reflection mirror 8, reflection mirrors 9a, 9b
, the halogen lamp 5 is attached to a slidable member with respect to the shaft 13.

On the other hand, the long microcapsule paper 12 is wound around a cartridge shaft 14 and housed in a cartridge 15 that can be removed from the machine body, and a magazine is used to set the cartridge 15 at a desired position in the machine body. There are 1,600 prepared. In the magazine 16, a roll 17a17 is used to sandwich a leader tape attached to the tip of the microcapsule paper 12 only during the initial paper feeding, and to send the microcapsule paper 12 to a predetermined conveyance path inside the machine.
b is provided.

The microcapsule paper 12 sent out from the cartridge 15 is guided to the tension roll 19 and placed on the exposure stage 11.
The dancer roll 21 is guided through drive rolls 20a and 20b which can be opened and closed. Microcapsule paper 1 whose slack is adjusted by dancer roll 21
2 reaches a winding shaft 24 via a pressure developing device 22 and a separation roll 23. Note that the unexposed microcapsule paper 12 after leaving the cartridge 15 is maintained in an unexposed state by a light shielding cover.

Further, the conveyance speed of the microcapsule paper 12 is controlled by a drive roll 20 on the upstream side of the dancer roll 21.
On the downstream side, it is controlled by a pressure fixing device 22 and a separation roll 23. The feeding speed of the drive roll 20 is synchronized with the moving speed of the halogen lamp 5, lens 7, and mirror group 8.9a, 9'b as described above. Therefore, as the halogen lamp 5, lens 7, and mirror groups 8.9a and 9b move to scan the original 4, a latent image of a predetermined run of the original 4 is formed on the microcapsule paper 12 as it passes through the exposure stage 11. Formed sequentially.

A paper feed cassette 29 containing paper (hereinafter referred to as developer paper) 28 constituting the paper feed device is installed below the pressure developing device 22, and a suction cup-shaped suction cup that sucks the paper using negative pressure suction is installed. A paper feeding mechanism 30 is provided. Developing paper 2
8 is a feed roll 31a from which sheets are taken out one by one by the paper feed mechanism 30.

31b and carried into the pressure developing device 22.

When the top of the portion of the microcapsule paper 12 on which the latent image is formed comes, the pressure development device 22 performs nipping together with the color developer paper 28 . In this way, the microcapsule paper 12
The latent image formed on the surface of the microcapsules and the developer paper 2
The developer-coated surfaces of No. 8 are sandwiched between the large-diameter roll 22a and the backup roll 22b while being in contact with each other on the inside, and pressure is applied. This pressure destroys the unexposed microcapsules and forms an image on the developing paper 28. The microcapsule paper 12 and the color developer paper 28 discharged from the pressure developing device 22 are separated by a separation roll 23. Thereafter, the color developing paper 12 on which the image has been formed by promoting color development by the heat fixing device 32 is discharged onto a paper discharge tray 33 by a paper discharge roll 32a. The separated microcapsule paper 12 is passed through a separation roll 23 and wound onto a winding shaft 24.

Here, the structure of the paper feeding mechanism 30 will be explained with reference to FIG. The suction cup 71 is a rotatable elevator arm (
The mounting attached to the rotating arm (hereinafter referred to as the rotating arm) 72 is attached to the plate 72a. The bottom of the suction cup 71 is connected to a negative pressure generating means 55 via a flexible tube 54.

This negative pressure generating means 55 includes a cylinder 56, a piston 58 having an O-ring 57, gears 59, 60, a step motor 61, and the like. The step motor 61 can arbitrarily rotate a fan-shaped gear 59 around a shaft 62 via a gear 60 attached to its output shaft.

The fan-shaped gear 59 is connected through a pin 63 provided near its outer periphery and an elongated hole provided in the piston rod 64.
It is interlocked with the piston 58. The rotating arm 72
is rotatably supported on a rotation shaft 74 that can be raised and lowered.

The rotation shaft 74, which is the center of rotation of the suction cup 710, is the rotation center of the suction cup 71.
The suction cup 71 has its center on an extension line of the suction surface, and is located on the rear side with respect to the conveyance direction of the color developer paper 28 than the part where the suction cup 71 attracts the color developer paper 28 . Note that the suction cup 71 is arranged so as to attract the color developer paper 28 at a relatively front portion with respect to the front and rear of the conveyance direction of the color developer paper 28 .

Further, a mounting plate 72b is attached to the rotating arm 72 at a predetermined angle from the mounting plate 72a. A sensor 73 for detecting the uppermost surface of the color-developing paper is attached to the plate 72b, which is comprised of a microswitch or the like. Here, when the plate 72b is mounted in the vertical direction, the sensor 73 and the rotating shaft 74 are in a relationship such that they are located on the same horizontal plane.

Further, the paper feed cassette 29 is housed in a cassette receiver 34 provided in the main body of the image forming apparatus, as shown in FIG. 35 (sheet discrimination means) is provided. Paper feed cassette 2 facing reflective photo sensor 35
A portion of the side wall 9 is cut out, and light is projected from the reflective photosensor 35 through the cutout 36 toward the side edge of the developer paper 28 stored in the paper feed cassette 29 .

A package 28 of color developer paper 28 is bundled to a certain thickness and is stored in a paper feed cassette 29.
There is a bar code 37 on the side that indicates the type of color developing paper 28.
is printed.

When light is projected onto the barcode 37 of the package 28 from the reflective photosensor 35, a signal is output from the reflective photosensor 35 to the microcomputer 38 as shown in FIG. The microcomputer 38 stores optimal suction amount data 39 when the suction cup 71 sucks the color developer paper 28, depending on the type of the color developer paper 28.

Furthermore, based on the signal from the reflective photosensor 35,
A suction amount data switching unit 40 for switching to the optimum suction amount data 39, and a control means 42 that outputs a drive signal to the drive circuit 41 based on the switched optimum suction amount data 39.
have. When a drive current is passed from the drive circuit 41 to the step motor 61 based on the drive signal, the step motor 61 rotates by a predetermined amount. The piston 5 is rotated by a predetermined amount of rotation of the step motor 61 through the gears 59 and 60.
8 is lowered to generate a negative pressure in the suction cup 71 according to the type of color developing paper 28.

Next, the paper feeding operation of the paper feeding device 30 will be explained with reference to FIGS. 5A to 5. Initially, the rotating arm 72 is mounted above the developer paper 28 as shown in FIG.
is positioned vertically so that the sensor 73 can detect the top surface of the color developing paper 28 first. In response to the command to start paper feeding, the rotating arm 72 moves downward in the direction of the arrow in FIG. 5A. When the sensor 73 reaches the uppermost surface of the color developing paper 28, the rotation arm 72 stops descending.

At that position, the rotating arm 72 rotates around the shaft 74 until the suction cup 71 is horizontal to the uppermost surface of the developing paper 28, as shown in FIG. 5B.
Rotate in the direction of arrow B inside. In this state, the pressure reducing means 55
This generates negative pressure inside the suction cup 71, and the topmost color developing paper 28
is sucked into the suction cup 71.

Here, the operation of the suction cup 28 will be explained with reference to the flowchart shown in FIG. When the paper feed cassette 29 containing the developer paper package 28 is placed in the cassette holder 34, the reflective photosensor 35 emits light toward the barcode 37 of the package 28 to determine the type of developer paper 28 ( Step S1). From the reflective photosensor 35 to the microcomputer 38 depending on the type of color developing paper 28
A signal is output to, and the suction amount data switching section 39 switches to the optimal suction amount data 39 (step S2).
. A drive signal is output from the control unit 42 to the drive circuit 41 based on the suction amount data 39 (step S3). The step motor 61 is driven based on the drive signal from the drive circuit 41.
When the drive current is applied to the step motor 61, the step motor 61 rotates by a predetermined amount (step S4). When the step motor 61 rotates a predetermined amount, the piston 58
moves by a predetermined stroke, and a negative pressure corresponding to the type of color developing paper 28 is generated in the suction cup 71 (step S5). That is, if the base paper of the color developer paper 28 is thick and stiff, the negative pressure inside the suction cup 28 is increased, and on the other hand, when the base paper of the color developer paper 28 is thin and weak, the negative pressure inside the suction cup 28 is decreased. .

Next, with the suction cup 71 suctioning the developer paper 28, the rotating arm 72 is rotated in the direction A in FIG. 5B, resulting in the state shown in FIG. 5C. By maintaining this state for a predetermined time, the suction cup 7
In step 1, the uppermost 28 sheets of color developer paper are separated using the stiffness of the color developer paper 28. Then move upwards as shown in the fifth diagram, arrow C.
The rotating arm 72 is moved in the direction shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, the type of paper stored in the paper feed cassette is determined by the paper discrimination means, and the suction amount data switching section switches to suction amount data suitable for the stored paper. Since the drive of the negative pressure generating means is controlled by the control unit based on the suction amount data, no matter what kind of paper is stored in the paper feed cassette, the suction amount of the suction cup is selected accurately and the paper Paper is reliably fed without double feeding to a pressure phenomenon device or paper feeding failure.

[Brief explanation of drawings]

1 to 6 are diagrams showing an embodiment of a paper feeding device in an image forming apparatus according to the present invention, FIG. 1 is a sectional view of the image forming apparatus, and FIG. 2 is a partial sectional view of the paper feeding device. Front view,
FIG. 3 is a perspective view of the paper discriminating means, FIG. 4 is a control block diagram of the paper feeding device, FIGS. 5A to D are diagrams showing the operation of the paper feeding device, and FIG. 6 is a flowchart of the paper feeding device. be. 28... Suction cup, 29... Paper feed cassette, 35...
Reflective photosensor, 39... Amount of suction data, 40.
... Suction amount data switching unit, 41... Control unit, 55...
・Cylinder, 61...Step motor.

Claims (1)

[Claims] A paper feed cassette in which paper is stored, a suction cup for taking out the paper by suction from the paper feed cassette, a negative pressure generating means for generating negative pressure for the suction cup to suck the paper, and a negative pressure generating means for generating negative pressure for the suction cup to suck the paper; a paper discrimination means for discriminating the type of stored paper; a suction amount data switching unit having suction amount data according to the type of paper and switching to suction amount data suitable for the stored paper; A paper feeding device for an image forming apparatus, comprising: a control section that controls driving of the negative pressure generating means based on suction amount data switched by a data switching section.