JPH0553698B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic document feeder that is installed in an image forming apparatus such as a copying machine or a facsimile machine and automatically feeds documents.

Prior Art The outline of an automatic document feeder used in a dry type electrophotographic copying machine is illustrated and explained in FIG.

A platen glass 02 serving as a document mounting table is attached to the top surface of the copying machine body 01.
An original placed at a predetermined position on the photosensitive material 2 is irradiated with light from an exposure lamp inside the machine, and the reflected light forms a latent image on the sensitive material.

Automatic document feeder 03 is located above the top of this copying machine.
will be installed.

Above the platen glass 02, a pulley 04,
A conveyor belt 06 spanned over the conveyor belt 05 is located, and there is a gap of about 1 mm between the conveyor belt 06 and the platen glass 02.

In FIG. 5, the document is inserted between the platen glass 02 and the conveyor belt 06 by the right conveyor roller 07, and the document continues to be transferred to the conveyor belt 06.
6, it is conveyed over the platen glass 02, stopped at a predetermined position, and subjected to the exposure as described above.

The exposed original is again conveyed by the conveyor belt 06 and conveyed by the left roller 08.

Problems to be Solved by the Invention Since the automatic document feeder automatically transports documents as described above, it is convenient for copying a plurality of documents.

However, since the document is conveyed on the platen glass, there is a slight gap between the conveyor belt and the platen glass, so the document is not brought into close contact with the platen glass even during exposure. If there is, there is a risk of poor resolution or poor magnification.

The present invention has been devised in view of the above, and an object of the present invention is to provide an automatic document feeder that can bring a document into close contact with a platen glass by lowering a conveyor belt during exposure.

Means and Effects for Solving the Problems The present invention has a conveyor belt above the document table,
An automatic document feeder that automatically controls the conveyance of a document in a gap with a document placement table, comprising: a conveyor belt support means for supporting a conveyor belt; a slide shaft that supports the conveyor belt support means and is slidable up and down; a spring that supports the slide shaft in a vertically movable manner; a cam that moves the slide shaft up and down; a cam drive means for driving the cam; a conveyor belt drive means that drives the conveyor belt; and a joint member that transmits the drive of the means to the conveyor belt.

Therefore, during exposure, the cam is driven by the cam drive means to lower the slide shaft, and at the same time, the conveyor belt supporting means lowers the document so that the conveyor belt can press the document and bring it into close contact with the document table.

In addition, the slide shaft is supported in an upper position by a spring at times other than during exposure, and therefore the conveyor belt support means is also positioned upward, making it possible to provide a slight gap between the document placement table and the conveyor belt, and to drive the conveyor belt. The joint member transmits the drive by the means to the conveyor belt, thereby making it possible to convey the document.

Note that even if the conveyor belt support means moves up and down, the transmission of drive to the conveyor belt is guaranteed by the joint member.

Embodiment An embodiment according to the present invention illustrated in FIGS. 1 to 4 will be described below.

FIG. 1 is a plan view of the conveyor belt drive mechanism.
Four conveyor belts 1 are stretched around each pair of pulleys 2 and 3.

The four pulleys 3 on the right side have the same rotating shaft 4, and the rotating shaft 4 is connected to a drive shaft 7 supported by a frame 6 via a universal joint 5.

A pulley 9 on which a transport drive belt 8 is stretched is fitted onto the drive shaft 7 .

Therefore, when the conveyance drive belt 8 is driven by a conveyance drive motor (not shown), the conveyance belt 1 is driven via the pulley 9, the drive shaft 7, the universal joint 5, the rotation shaft 4, and the pulley 3, and the rotation shaft Even if there is slight vertical movement of the shaft 4, the drive can be transmitted through the universal joint 5.

The pulleys 2, 3, rotating shaft 4, etc. are mounted on a support frame 10.
Support pieces 11 are protruded from the front and rear side plates of the support frame 10 on the left and right sides, respectively.
1 has holes penetrating the top and bottom.

As shown in FIG. 2, a slide shaft 12 having heads at both upper and lower ends is passed through the hole in the support piece 11, and the slide shaft 12 is further fitted into the bottom plate of a bracket 13 fixed to the frame 6. It passes through the bush 14.

Upper head of slide shaft 12 and bush 1
A compression spring 15 is interposed between the slide shaft 12 and the slide shaft 12 by inserting the slide shaft 12 into its inner hole.
is supported upward.

The disc cam 16 is located in contact with the upper surface of the upper head of the slide shaft 12, and when the cam 16 rotates around the eccentric rotation center axis, the compression spring 1
A slide shaft 12 supported by 5 is slid up and down.

As shown in FIG. 1, four similar drive mechanisms using cams are arranged at four locations on the front, rear, left and right sides of the support frame 10, and the front and rear cams are connected to each other by the same camshaft 17.

The right camshaft 17 eccentrically fixes the cam 16, and a pulley 18 for interlocking the camshaft is fixed through the frame 6, and a step clutch 19 is provided at the tip.

The step clutch 19 has a rotating shaft 20 on the opposite side from the camshaft 17, and a pulley 21 for driving the camshaft is fixed to the rotating shaft 20.
A camshaft drive belt 22 that transmits the drive of a motor (not shown) is spanned.

The motor is driven by a camshaft drive belt 2.
2 to the rotating shaft 20, and further transmitted to the camshaft 17 via the step clutch 19, and the operation of the step clutch 19 controls the engagement and disengagement between the rotating shaft 20 and the camshaft 17. I can do it.

The step clutch 19 used in this embodiment is capable of transmitting a drive of one step and one rotation simultaneously with signal input.

A pulley 23 for interlocking the camshaft is fixed to the front end of the camshaft 17 on the left side through the frame 6, and a belt 24 for interlocking the camshaft is suspended between the pulley 18 provided on the camshaft 17 on the right side. It has been passed.

Therefore, when a cam drive signal is input to the step clutch 19 and the rotation of the rotary shaft 20 is transmitted to the camshaft 17, the two cams 16 on the right side, which share the same camshaft 17, rotate simultaneously, and the camshaft Interlocking belt 24
The movement is also transmitted to the left camshaft 17 through the camshaft 17, and the two cams 16 on the front and rear of the same camshaft 17 rotate. Therefore, the four cams on the front, rear, left and right sides rotate at the same time.

The four cams 16 have a diameter of 6 as shown in FIG.
The cams are disc cams with a diameter of 1.5 mm and are fixed to the camshaft 17 with an eccentricity of 1.5 mm, and the relative positions of the cams are the same.

Before the cam is driven, the slide shaft 12 is at its highest position with the cam 16 at its highest position, as shown in FIG. 4a, and when the cam rotates,
When the slide shaft 12 is pushed downward and rotates half a turn, the slide shaft 12 is moved 3 degrees from the highest position.
When the slide shaft 12 is lowered by mm, it becomes the lowest position (see FIG. 4b), and with the subsequent half rotation of the cam, the slide shaft 12 is raised by the force of the compression spring 15, returning to the state before driving.

FIG. 2 is a sectional view showing the cam mechanism before driving, and FIG. 3 is a sectional view showing the cam mechanism when the cam rotates half a rotation.

Support frame 10 supported by slide shaft 12
The conveyor belt 1 is lowered at the same time as the slide shaft 12 is lowered, but since the gap between the conveyor belt 1 and the platen glass 25 is approximately 1 mm, the gap is 1 mm.
After descending, the platen glass 25 is pressed by its own weight and stopped, and is supported by the platen glass 25.

However, the slide shaft 12 continues to slide further down through the hole in the support piece 11.

The slide shaft 12 descends 3 mm from the highest position, then moves upward, and when it rises approximately 2 mm, it supports the support frame 10 and the conveyor belt 1, and then moves up to the final 1 mm.
are raised together to form a gap between the platen glass 25 and the conveyor belt 1.

Therefore, after the slide shaft 12 is lowered by 1 mm from the highest position, the conveyor belt 1 is in a state of pressing the platen glass 25 until it returns to 1 mm from the highest position after passing through the lower position.

Since the conveyor belt 1 moves up and down as described above, the conveyor belt 1 is normally in the raised position.
When a gap of approximately 1 mm is formed between the original and When stopped, a cam drive signal is input to the step clutch 19, and the cam 16 rotates to lower the conveyor belt 1 and press the original onto the platen glass 25.

Flash exposure is performed while the original is pressed, the cam rotates more than half a turn, the conveyor belt 1 rises, and then the original is conveyed and discharged by the drive of the conveyor belt 1.

As described above, in this embodiment, a sufficient gap is formed between the platen glass 25 and the conveyor belt 1 during document conveyance to ensure smooth conveyance, and the document is pressed against the platen glass 25 by the conveyor belt 1 during exposure. Copies with poor resolution or poor magnification due to wrinkles, creases, etc. can be prevented.

Although this embodiment is directed to a flash exposure type copying machine, it is also applicable to a slit exposure type copying machine.

In the case of slit exposure, since it takes a certain amount of time for the light to scan the surface of the document, it is necessary to press the document against the platen glass 25 with the conveyor belt 1 during that time.

To do this, the step clutch 19 is set to 2 steps per rotation, the cam is rotated half a turn by the first drive signal, the conveyor belt 1 is lowered to press the original, and slit exposure is performed, and the second exposure is performed after a predetermined period of time has elapsed. The drive signal may be used to cause the cam to rotate the remaining half turn to raise the conveyor belt 1.

Effects of the Invention The present invention can fix the original on the original placing table from above during exposure, thereby correcting wrinkles and folds in the original, preventing poor resolution, and obtaining high-quality copied images with proper exposure. I can do it.

Furthermore, since an appropriate gap can be formed between the document mounting table and the conveyance belt when conveying the document, jamming of the document can be prevented and smooth conveyance can be achieved.

Conventionally, the gap between the document placement table and the delivery belt needs to be narrow in order to hold the document for proper exposure, and it needs to be wide in order to convey the document smoothly. Since the width was adjusted to a satisfactory level, precision was required to manage the width, but according to the present invention, the width can be managed only roughly, making it easy to manufacture.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a conveyor belt drive mechanism according to an embodiment of the present invention, Fig. 2 is a sectional view showing the cam mechanism before driving in the same embodiment, and Fig. 3 is a cam mechanism when the cam rotates half a turn. FIG. 4 is an explanatory diagram for explaining the rotational state of the cam, and FIG. 5 is a schematic explanatory diagram of the automatic document feeder. 1... Conveyor belt, 2, 3... Pulley, 4...
...Rotation axis, 5...Universal joint, 6...
... Frame, 7 ... Drive shaft, 8 ... Conveyance drive belt, 9 ... Pulley, 10 ... Support frame, 11 ...
...Support piece, 12...Slide shaft, 13...
... Bracket, 14 ... Button, 15 ... Compression spring, 16 ... Cam, 17 ... Camshaft, 18 ... Pulley, 19 ... Step clutch, 20 ... Rotating shaft, 21 ... Pulley, 22 ...
...Camshaft driving belt, 23...Pulley, 24...Camshaft interlocking belt, 25...
...Platen glass.

Claims (1)

[Claims] 1. In an automatic document feeder that has a conveyor belt above the document table and automatically controls the conveyance of the document in the gap between the document table and the document table, there are provided a conveyor belt support means for supporting the conveyor belt, and a conveyor belt support means for supporting the conveyor belt. A slide shaft that supports and can slide up and down, a spring that supports the slide shaft so as to be able to move up and down, a cam that moves the slide shaft up and down, a cam drive means that drives the cam, and a cam drive means that drives the conveyor belt. and a joint member that transmits the drive of the conveyor belt drive means to the conveyor belt, and the conveyor belt can be positioned upward during document conveyance and lowered during exposure to press the document. Automatic document feeder.