JPH07107611B2 - Document feeder - Google Patents

Description

The present invention relates to a document feeder used in an electronic copying machine.

(Prior Art) An electronic copying machine exposes a charged photosensitive drum according to document information, and then forms a visible image of toner on an electrostatic image formed on the surface of the drum. A device that transfers an image onto recording paper. In recent years, this type of electronic copying machine has been widely used for information copying in all fields of industry. In addition, recent electronic copiers are available on the market that have a zoom function for image enlargement / reduction in addition to automatic copying of a preset number of copies, and also have an automatic document feeding mechanism. There is.

A document feeder having an automatic feeding mechanism is placed on a document table (platen) of an electronic copying machine, and a document from a tray
Documents are conveyed one by one onto the document table, and the documents that have been copied are ejected.

(Problems to be Solved by the Invention) Some document feeders (ADFs) of this type are equipped with an automatic document reversing mechanism to enable double-sided copying of a document with information recorded on both sides. . In the conventional apparatus of this type, a drive source (motor) is provided in each of the document conveying mechanism and the document automatic reversing mechanism. Therefore, motor control is required for each of the document feeding mechanism and the automatic document reversing mechanism,
One encoder for each motor to detect the number of rotations of the motor
I needed two in total. Therefore, since the information from the two encoders is processed to control the respective motors, the control such as the synchronous control is complicated, the cost is high, and the device is large.

The present invention has been made in view of such points,
The purpose is to realize a compact document feeder which is easy to control and low in cost.

(Means for Solving Problems) According to the present invention for solving the above-mentioned problems, an original is conveyed onto a platen, and after one-sided copying is completed, the document on the platen is returned to reverse the front and back sides. In a document feeder that conveys a document onto the document table again, by switching the moving direction of the conveyor belt, the document is conveyed to the document table in the forward direction and the document that has already been conveyed onto the document table is returned. And an original conveying mechanism for carrying out a reverse conveying operation for receiving the original returned by the reverse conveying operation of the original conveying mechanism after completion of copying one side of the original, and makes the original U-turn again. A document reversing / conveying mechanism to be passed to the document conveying mechanism, one motor capable of rotating in the normal and reverse directions, and the conveying belt in the document conveying mechanism to perform the conveying operation in the forward direction when the motor rotates in the normal direction, When the motor reverses, the original A first transmission means for transmitting the driving force of the motor to the conveyor belt so that the conveyor belt in the document conveyor mechanism performs the reverse conveying operation.
Drive force transmission mechanism and a pair of gears meshed with each other so as to rotate in opposite directions by the motor, one-way clutch for transmitting the drive force in the same direction is connected to each of the gears, A second drive force transmission mechanism for transmitting a drive force obtained through a one-way clutch to a document conveyance roller in the document inversion conveyance mechanism, and rotation of the motor to obtain a signal for speed control of the motor. And an encoder for detecting the number, and switching from the reverse rotation to the normal rotation of the motor during the reverse operation of the front and back sides of the document is performed in the conveyance direction of the document during the conveyance operation in the reverse direction by the conveyance belt. This is performed after the leading edge of the document reaches the document transport roller in the document reversing transport mechanism.

(Operation) According to the present invention, the motor drive of the document feeding mechanism and the document reversing feeding mechanism is controlled by one encoder.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a structural conceptual diagram showing an embodiment of the present invention. In the figure, 1 is a tray on which a plurality of originals 2 are placed, R ₁ is a delivery roller for delivering the originals 2 described on the tray 1 to a transport mechanism, 3 is rollers R ₂ , R ₃ , these rollers R ₂ , R ₃
The first transport mechanism G ₂ is transported by the first transport mechanism 3 including the belt V ₁ , which is wound between the rollers, the roller R ₄ and the first paper feed guide G ₁ which are arranged at the opposite positions. The second guides R ₅ and R ₆ for guiding the incoming document 2 are the second guides G ₂
It is a document feeding roller provided in a part. 4 is a roller
R ₇ through R ₁₂ and roller R _7, consisting of R ₁₂ belt V ₂ wound between the second transport mechanism 5 is a platen which a document is placed copying operation is performed (the platen). As the document table 5, for example, glass is used to transmit light.

Reference numeral 6 denotes an original reversing / conveying mechanism including three pairs of rollers R ₁₃ , R ₁₄ , R ₁₅ , R _16, R ₁₇ and R ₁₈ and a third original guide G ₃ . Reference numeral 7 is a motor for giving a driving force to the conveyance mechanism shown in the figure, and 8
Is an encoder for detecting the rotation of the motor mounted on the rotary shaft 7a of the motor 7. The output of the encoder 8 is fed back to a motor drive circuit (not shown) to drive the motor 7
Used to control the rotation of the. The operation of the apparatus thus configured will be described below.

First, the document 2 placed on the tray 1 is placed on the transport mechanism by the delivery roller R _{1 and} is transported to the document table 5 by the route shown by the arrow in FIG. Original 2 at this time
As shown in FIG. 2B, the A side is the front side (the side to be copied) and the B side is the back side. In this state, side A is copied. When the copying of the side A is completed, the motor 7 gives a driving force to the conveying mechanism shown in the figure, causing the original 2 to make a U-turn along the route shown by the arrow in FIG. 2C, and again as shown in FIG. Send to table 5. As a result, the document 2 on the document table 5 is turned upside down as shown in (e). That is, (b)
Contrary to the case of, the B side is the front side (the side to be copied) and the A side is the back side. Therefore, when copying is performed in this state, the B-side copy is performed, and the double-sided copy of the original 2 is completed.

The motor 7 gives a driving force to the transport mechanism during this transport operation. During the rotation operation of the motor 7, the encoder 8 attached to the rotation shaft of the motor 7 always detects the rotation speed. Then, a drive circuit (not shown) performs negative feedback control so that the motor rotation speed detected by the encoder 8 becomes a predetermined value. According to the present invention, since the document transport mechanism and the document reversing transport mechanism are driven by one motor, only one encoder for detecting the rotation speed of the motor is required. Therefore, the control is simple and the number of mechanical parts is small, and it is possible to realize a low-cost, compact document feeder.

FIG. 3 is a mechanical configuration diagram showing a specific embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals. Reference numeral 7 is a motor, and 8 is an encoder attached to the rotating shaft 7a of the motor 7, which has been described above. Reference numerals 11 to 13 denote reversing unit driving roller shafts, 14 denotes a conveyor belt driving shaft, and 15 denotes a second paper feeding roller shaft (corresponding to R ₆ in FIG. 1). The solid line wound between the rollers is a belt for transmitting driving force. A driving force is applied from the motor 7 to all of these belts.

C ₁ and C ₂ are roller shafts with built-in one-way clutches that act in opposite directions, and the power is transmitted to C ₂ during normal rotation of the motor shown in Fig. 2 (a), and the motor shown in Fig. 2 (c). During reverse rotation, power is transmitted to C ₁ . G _5, G ₆ is a gear mounted coaxially one with way clutch roller axes C _1, C _2, respectively, P ₇ is conveyance belt drive flop - Li, P _14, P _15, each R ₁₇ reversing section rollers driven pulley Is.

The original sent from the tray (not shown) is sent to the original table (not shown) by the route shown by the arrow in FIG. 4 (a) (motor forward rotation). Next, the copy-finished document shown in FIG. 1 is U-turned as shown by an arrow in FIG. 4B so that the inside and the outside are reversed (motor reverse rotation) and sent to the document table (motor forward rotation). , The second side is copied. In these operations, the reversing unit drive roller shafts 11 to 13 are always rotating in the same direction (clockwise), and the motor 7 is used for the first surface copy shown in FIG. The direction of rotation reverses when the document is reversed as shown in). As described above, according to the present invention, the document can be conveyed and the document can be reversed by performing the control for changing the rotation direction of the motor.
Only one motor is required even when copying both sides of a document.

The switching of the motor 7 from the reverse rotation to the forward rotation during the reverse operation of the front and back of the original 2, in other words, the transition from the state of FIG. 2C to the state of FIG. The leading edge of the document in the transport direction of the document 2 during the reverse transport operation is the document transport roller in the document reverse transport mechanism 6.
It may be performed after reaching R ₁₇ and R ₁₈ (after the leading edge of the document reaches the document transport rollers R ₁₇ and R ₁₈ in the document reversing transport mechanism 6, even if the moving direction of the transport belt is changed thereafter,
Since the conveying force of the document conveying rollers R ₁₇ , R ₁₈ is stronger than the conveying force of the conveying belt, the document 2 is conveyed by the document conveying rollers R ₁₇ , R ₁₈ .
₁₈ pulled, never returned). The output signal of the encoder 8 is not used for the timing of switching from the reverse rotation of the motor 7 to the normal rotation. As described above, the encoder 8 detects the rotation of the motor 7 and feeds back the output signal to the motor drive circuit to control the rotation of the motor 7, in other words, the signal for speed control of the motor 7. Is to get.

Further, as in the configuration shown in FIG. 1, in order to receive the return original 2 from the original conveying mechanism (second conveying mechanism 4), the original entrance path (original) which forms substantially the same horizontal surface as the upper surface of the original table 5 is formed. By providing a conveyance path near the entrance of the guide G _3, the original 2 returned from the original conveyance mechanism (second conveying mechanism 4) is flat due to its rigidity, and thus the original 2 can be smoothly moved. It is convenient for the inside of the reversing conveyance mechanism 6 to enter.

(Effects of the Invention) As described above, according to the present invention, the moving direction of the transport belt in the document transport mechanism is switched according to the forward / reverse rotation of one motor capable of forward / reverse rotation. A one-way clutch for transmitting the driving force of the motor to the conveyor belt, on the other hand, a pair of gears meshed so as to rotate in opposite directions by the motor, and transmitting the driving force in the same direction to each of the gears are provided. An encoder is provided which is connected to transmit the driving force obtained through the two one-way clutches to the document conveying roller in the document reversing and conveying mechanism and which detects the rotation speed of the motor. Based on the above, the drive control of the motor is carried out so that the document transport mechanism and the document reversal transport mechanism can transport the document.
Since it is possible to drive with one motor and only one encoder is required, it is possible to realize a document feeder which is easy to control, low in cost and compact.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration of an embodiment of the present invention, FIG. 2 is a diagram showing a document transportation route, FIG. 3 is a mechanical configuration diagram showing a specific embodiment of the present invention, and FIG. The figure is a diagram showing the conveyance direction of a document. 1 ... Tray, 2 ... Originals 3,4 ... Transport mechanism, 5 ... Original table 6 ... Original reversing / conveying mechanism 7 ... Motor, 7a ... Rotating shaft 8 ... Encoder 11 to 13 ... Reversing unit Drive roller shaft 14 …… Conveyor belt drive shaft 15 …… Second paper feed roller shaft R _{1 to} R ₁₈ …… Roller V ₁ , V ₂ …… Belt, G ₅ , G ₆ …… Gear P ₇ …… Conveyor belt Drive pulleys P ₁₄ , P ₁₅ , P ₁₇ …… Reversing part roller drive pulleys C ₁ , C ₂ …… Roller shaft with one-way clutch

Claims (2)

[Claims] 1. A document transporting apparatus for transporting a document onto a document table, returning the document on the document table after reversing the one side, reversing the front and back, and transporting the document again onto the document table. A document transport mechanism that performs a forward transport operation for feeding a document onto the document platform and a reverse transport operation for returning a document already transported on the document platform by switching the moving direction of After the copy of one side of the document is completed, a document reversing transport mechanism that receives the document returned by the transport operation of the document transport mechanism in the opposite direction, makes a U-turn of the document, and passes the document to the document transport mechanism again One motor and the transport belt in the document transport mechanism to perform the transport operation in the forward direction when the motor rotates in the forward direction, and the transport belt in the document transport mechanism to the reverse direction when the motor rotates in the reverse direction. Direction transport operation A first driving force transmission mechanism that transmits the driving force of the motor to the conveyor belt, and a pair of gears that are engaged by the motor so as to rotate in opposite directions. A two-way clutch for transmitting the driving force in the same direction is connected to each of the second one-way clutches, and the driving force obtained through the two one-way clutches is transmitted to the document conveying rollers in the document reversing and conveying mechanism.
And a encoder for detecting the number of rotations of the motor in order to obtain a signal for controlling the speed of the motor, and from the reverse rotation of the motor during the reverse operation of the front and back of the document. The switching to the normal rotation is performed after the leading edge of the document in the transport direction of the document during the transport operation in the reverse direction by the transport belt reaches the document transport roller in the document reverse transport mechanism. Document feeder. 2. The original reversing / conveying mechanism is provided with an original entry path that forms a substantially horizontal plane with the upper surface of the original table for receiving a returning original from the original conveying mechanism. The document feeder according to claim 1.