JPH05289191A - Position detection device for original platen - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to save space. CONSTITUTION:Original platen locking-prevention control is carried out by a control system 42 to prevent an original platen 2 from being locked on an edge part side of a copying machine main body 1. This control is carried out based on a signal fed from the position detection circuit 23, that is, the signal corresponding to change in quantity of current escaping through a bracket 11 when the bracket 11 is slid by first conductive parts 21 and 21 in outer periphery surface of an endless rack 8 and second conductive parts 31 and 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document table position detecting device for detecting the position of a document table, which is provided in a document table moving type copying machine in which a document table moves during a copying operation. is there.

[0002]

2. Description of the Related Art Generally, in an original table moving type copying machine, when an original on the original table is scanned by an optical system, the original table first moves from an initial position to a scanning start position in a return direction, and then, After the document is scanned by moving in the feed direction to the scanning end position, it is moved from the scanning end position to the original initial position in the return direction.

As shown in FIG. 5, a document table driving device 51 for moving the document table 52 as described above is provided below the document table 52 and has a structure as shown in FIG. When moving from the scanning start position to the feed (F) direction, the feed solenoid 53 is turned on, whereby the latch 54 engages with the clutch brake 56 of the feed spring clutch 55, and the feed spring clutch 55. Becomes a combined state.

Therefore, the driving force input to the input gear 57 is transmitted to the output gear 58 and further to the document table driving gear 59. The original table drive gear 59 meshes with a rack (not shown) fixed to the lower surface of the original table 52, and the original table 52 provided with this rack moves in the feed direction as the rack moves.

After that, when the document table 52 reaches the scanning end position, this state is detected by the detection switch 60,
The feed solenoid 53 is turned off and the return solenoid 61 is turned on. As a result, the latch 62 causes the clutch brake 63 of the return spring clutch 67 to be released.
And the return spring clutch 67 is engaged. Therefore, the driving force input to the input gear 57 is transmitted to the platen drive gear 59 via the gear 64, the input gear 65, the output gear 66 and the output gear 58,
The document table 52 moves to the initial position in the return (R) direction.

However, in the above conventional structure, the feed spring clutch 5 is used to reciprocate the document table.
5, devices such as the return spring clutch 67, the feed solenoid 53, and the return solenoid 61 are necessary, and the ratio of the cost occupying each device as described above becomes high, which causes an increase in the cost of the device. Had.

Therefore, in order to reduce the number of parts, an original platen moving type copying machine provided with an endless rack type original platen drive device has been considered. As shown in FIG. 7, the endless rack type document table driving device 71 includes two rack portions 73a provided in parallel with their tooth surfaces facing each other.
73b, and two semi-circular gear portions 73 having inner teeth arranged in a semi-circular shape that connect the end portions of both rack portions to each other
The endless rack 73 composed of c · 73d receives the driving force from the input gear 75 to which the driving force of the motor provided inside the endless rack 73 is input, between the input gear 75 and the endless rack 73. Is linearly moved by being transmitted through a planetary gear 76 provided so as to mesh with both of these gears.
2 is moved back and forth.

However, with the above-mentioned structure, the number of parts is reduced and the problem of increased cost of the apparatus is solved, but in the above copying machine, the original table 72 is located at the end side of the copying machine main body. When the power is turned off in this state, the planetary gear 76 and the semi-circular gear portion 73c or the semi-circular gear portion 73d of the endless rack 73 remain engaged with each other.
2 is locked and cannot be moved by external force. This significantly reduces the work efficiency of trouble handling such as paper jam.

Therefore, in a copying machine which adopts the endless rack type document table driving device 71, a rack 73b is used.
Switch operating parts 78, 78 on both ends of the rack 73b
A turn detection switch 77 is provided in the vicinity of the center of the copying machine, and the fact that the original table 72 is located on the end side of the copying machine main body is detected by turning on the turn operation detection switch 77 by the switch operating section 78. And turn detection switch 77
While is ON, the main motor (not shown) that drives the planetary gear 76 is not stopped even if the power is turned off.

[0010]

However, in the above structure, the fact that the original table 72 is located on the end side of the copying machine main body means that the turn portion detecting switch 77 and the switch operating portion 78 are separate members.・ Since the number of parts is increased because it is detected by 78, an extra space is required as a mounting place, and in general, the apparatus is downsized in a copyboard moving type copying machine, which is generally small and has many low-priced models. Is causing problems such as failure to achieve

[0011]

In order to solve the above-mentioned problems, a document table position detecting device according to the present invention has two rack portions provided in parallel with their tooth surfaces facing each other, and both racks. An endless rack having two semi-circular gears having inner teeth arranged on a semi-circle, which are connected to each other, and which are connected to a document table and linearly movable; Drive side gear that meshes with the endless rack,
A bracket that supports the drive-side gear and slides on the end surface of the endless rack is provided, and the sliding contact surface of the endless rack on which the bracket slides has a predetermined resistance value in a region corresponding to both rack portions. Is provided with a first conductive portion having a second conductive portion having a resistance value different from that of the first conductive portion in a region corresponding to both semi-circular gear portions. It is characterized in that a position detection circuit that emits an electric signal according to the electric resistance between is provided.

[0012]

According to the above construction, since the resistance value of the sliding contact surface of the endless rack on which the bracket slides is different between the rack portion and the semicircular gear portion, when the bracket slides on the endless rack. The signal detected by the position detection circuit changes in response to the change in the resistance value of the sliding contact surface. From this change in the electric signal, it is detected that the bracket is located at the semicircular gear portion, that is, that the document table is located at the end portion side of the copying machine main body.

As a result, the position of the platen can be adjusted by the endless rack and the bracket, which have been conventionally used, without separately mounting the turn detecting switch and the switch operating part on the endless rack and the vicinity of the endless rack as in the conventional case. Can be detected. As a result, it is possible to reduce the number of parts and save space.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In the copying machine provided with the position detecting device of the original table of the present embodiment, as shown in FIG. 2, the original table 2 on which the original 25 is placed is placed in the return direction on the upper surface of the main body 1 of the copying machine. Alternatively, it is provided so as to be movable in the feed direction, and the document placing portion of the document table 2 is formed of a transparent member such as a glass plate.

An optical system 20 including an irradiation lamp 15 and a rod lens array 24 is provided above the copying machine body 1. Below the optical system 20, an optical system 20 is provided.
The photoconductor 13 is provided. The photoconductor 13 is rotatably attached, and is attached to the original 2 from the irradiation lamp 15.
5 is exposed by the reflected light of the light emitted toward 5, and the residual potential is removed by the direct light from the irradiation lamp 15.

Around the photoconductor 13, a main charger 14 for charging the photoconductor 13 is disposed in contact with the photoconductor 13, and a stirring roller 26 rotatably provided.
And toner conveying rollers 27 and 28, and toner carrier 2
9 and the like are internally provided, and the photoconductor 1 is exposed by the exposure operation of the optical system 20.
Developing device 30 for developing the electrostatic latent image formed on the toner image 3 with toner, a transfer roller 12 for transferring the toner image formed by this developing operation onto a transfer sheet, and the photoreceptor 1.
3 collects the residual toner on the surface of the toner and the toner storage unit 1
A cleaning device 17 and the like to be accommodated in the No. 8 are provided.

A transfer section 32 is provided in the supply direction of the transfer sheet to the photoconductor 13, and further in the supply direction.
A paper feeding unit 33 is provided. The paper feed unit 33 includes a manual feed tray 34 for storing transfer paper, and the manual feed tray 34.
The transfer unit 32 includes a paper feed roller 35 and the like that takes out the transfer papers one by one from the transfer paper, and positions the transfer papers in the transfer direction.
It is designed to feed paper.

On the other hand, the transport section 32 is composed of a sheet input sensor 36 for detecting that the transfer sheet has been loaded in the transport section 32, a registration roller 16 for temporarily stopping the transfer sheet, and the like. The transfer paper supplied from is conveyed between the transfer roller 12 and the photoconductor 13 at a predetermined timing.

Further, jam sensors 38 and 39 for detecting the position of the jammed paper when a jam occurs and a fixing device 19 for fixing the toner image on the transfer paper are arranged in the conveying direction of the transfer paper from the photoconductor 13. Etc., and further,
A paper discharge sensor 37 is provided in the conveyance direction of the fixing device 19 to detect that the transfer paper has passed through the fixing device 19 and has reached a paper discharge unit (not shown).

The copying operation of the copying machine having the above-mentioned structure will be described. In the copying operation, the original table 2 on which the original 25 is placed has the end portion on the feed (F) direction side of the main body 1 of the copying machine. From a position substantially coincident with the initial position P ₁ , first to a scan start position P ₂ in the return direction (R), then to a scan end position P ₃ in the feed direction, and then to the original position P ₁ Move to. While the document table 2 moves from the scan start position P ₂ to the scan end position P ₃ , the optical system 20 scans the document with light, and the irradiation lamp 15 irradiates the document, and the reflected light is reflected by the rod. It is incident on the photoconductor 13 via the lens array 24.

As a result, the main charger 14 exposes the photoconductor 13 uniformly charged to a predetermined potential, and an electrostatic latent image corresponding to the original image is formed on the surface of the photoconductor 13. This electrostatic latent image is developed into a toner image by the developing device 30, and this toner image is transferred onto the transfer sheet by the transfer roller 12 applying a voltage having a polarity opposite to that of the toner to charge the transfer sheet. It After that, it is conveyed toward the fixing device 19,
After being thermally fixed to the transfer paper by the fixing device 19, the paper is ejected to the outside of the copying machine main body 1.

On the other hand, the movement of the original table 2 during the copying operation as described above is performed by the drive output gear 9 (driving side gear), the two-stage gear 10 (driving side gear), and the endless rack 8 shown in FIG. This is performed by the document table driving device 3 including the.

The document table driving device 3 is arranged on one side of the copying machine main body 1 in the reciprocating direction of the document table 2 so as to hang down from the edge of the document table 2. The platen drive device 3 includes two first and second racks (rack parts) 5
. 6 with teeth inwardly parallel to each other, one of the first
Semicircular return-side and feed-side internal teeth 7a and 7b extending from both ends of the rack 5 at the same pitch,
Each of the second racks 6 is formed toward the opposite end direction of the second rack 6, and the end faces are connected to each other. An endless rack 8 is formed by the racks 5 and 6 and the internal tooth portions 7a and 7b. The endless rack 8 is integrally formed with the support body 4 connected to the document table 2. There is. The outer peripheral surface of the endless rack 8 is a sliding contact surface 8a with which a bent portion 11a of a bracket 11 which will be described later is in sliding contact. A first conductive portion 21 and a second conductive portion 31 for detecting the position of are formed.

Inside the endless rack 8, a drive output gear 9 having a center at an intermediate portion from the outer peripheral surfaces of the first and second racks 5 and 6 is rotatably provided. Between the gear 9 and the first and second racks 5 and 6, there are provided two-stage gears 10 having different pitch circle diameters that integrally rotate on the same rotary shaft 10c. A rotary shaft 9a, which is a gear shaft of the drive output gear 9, is inserted into a guide hole 4a formed at a position parallel to and equidistant from the outer peripheral surfaces of the racks 5 and 6 in the support 4. .. The power of the main motor is transmitted to the rotary shaft 9a via a drive transmission mechanism (not shown).

The above-mentioned two-step gear 10 is a small and large gear 1.
0a and 10b, and the small gear 10a of the two-stage gear 10 is pitched so as to mesh with the first rack 5 and both internal tooth portions 7a and 7b, while the large gear in the two-stage gear 10 is provided. The pitch of 10b is set so as to mesh with the second rack 6. In other words, this allows the large gear 10
Endless rack 8 when b and the second rack 6 mesh with each other
Is faster than when the small gear 10a and the first rack 5 move in mesh with each other, and the moving speed of the document table 2 can be changed in the feed direction and the return direction. There is. The drive output gear 9 and the two-stage gear 10 are connected and supported by a bracket 11 that rotatably supports the respective rotary shafts 9a and 10c. A bent portion 11a is formed at one end of the bracket 11 so as to be bent at a substantially right angle so as to be parallel to the outer peripheral surface of the endless rack 8. The meshing of the two-stage gear 10, the drive output gear 9, and the endless rack 8 is ensured by sliding the outer peripheral surface of the rack 8 and moving the outer peripheral surface. The bracket 11 is formed of a conductive member and is grounded to detect the position of the document table 2. The details will be described later.

The operation of the document table driving device 3 will be described. When the small gear 10a of the two-stage gear 10 meshes with the first rack 5, the driving force from the main motor is input to the rotating shaft 9a of the driving output gear 9 so that the driving output gear 9 moves in the direction of arrow B. When rotated, the two-stage gear 10 rotates in the direction opposite to the drive output gear 9, and the endless rack 8
Moves linearly in the rotation direction of the two-step gear 10. As a result, the document table 2 connected to the endless rack 8 linearly moves in the feed direction (F).

Next, when the two-step gear 10 reaches the upper end of the internal tooth portion 7a on the return side, the small gear 1 of the two-step gear 10
0a meshes with the internal tooth portion 7a from the first rack 5 of the endless rack 8 and rotates around the drive output gear 9 about 180 ° about the rotation shaft 9a of the drive output gear 9 and descends. , Reaches the lower end of the internal tooth portion 7a.

After the small gear 10a reaches the lower end of the internal gear 7a, the meshing between the small gear 10a and the internal gear 7a is released, while the large gear 10b of the two-stage gear 10 moves. It comes to mesh with the second rack 6. As a result, the document table 2 moves together with the endless rack 8 in the return direction, which is the opposite direction to the previous direction.

After that, when the two-stage gear 10 reaches the lower end of the internal tooth portion 7b on the feed side, the meshing between the large gear 10b in the two-stage gear and the second rack 6 is released,
The small gear 10a comes into mesh with the inner tooth portion 7b on the feed side, and the small gear 10a is the rotating shaft 9 of the drive output gear 9.
Around the drive output gear 9, the drive output gear 9 is rotated by about 180 ° and rises to reach the upper end of the internal tooth portion 7b. Then, the small gear 10a again meshes with the first rack 5, and the movement of the document table 2 in the return direction is started.

When the endless rack 8 is reciprocally moved through the two-stage gear 10 by driving the drive output gear 9 as described above, the rotary shafts of the drive output gear 9 and the two-stage gear 10 are rotated. The bent portion 11a, which is one end of the bracket 11 that rotatably supports the 10c, is always
The sliding contact surface 8a of the endless rack 8 slides.

By the way, in the present copying machine, since the endless rack type manuscript table driving device 3 is adopted, when the manuscript table 2 is located on the end side of the copier body 1 due to its structure. That is, if the main motor is stopped while the two-stage gear 10 is meshing with the return-side internal tooth portion 7a or the feed-side internal tooth portion 7b, the document table 2 is locked and cannot be moved by an external force. Therefore, when the two-stage gear 10 meshes with the return-side internal tooth portion 7a or the feed-side internal tooth portion 7b, the control of the copying machine is performed so that the document table 2 is not locked even if the power is turned off. It is controlled by the system 42. Such a control system 4
The document table lock prevention control by 2 is performed based on a signal input from the position detection circuit 23 shown in FIG.

The position detection circuit 23 comprises a power source E having a predetermined electromotive force and a resistor R having a predetermined resistance value, and is connected to the sliding contact surface 8a of the endless rack 8. In this embodiment, the electromotive force of the power source E is set to 5 V and the resistance value of the resistor R is set to 3 kΩ.

The sliding contact surface 8a, to which the position detecting circuit 23 is connected, is covered with a conductive member having a resistance value which differs for each predetermined region, and the first rack 5 and the second rack 5
The region corresponding to 6 is covered with a carbon conductor having a resistance value of about 100Ω, and the first conductive portions 21 are formed. On the other hand, the return-side and feed-side internal tooth portions 7
The regions corresponding to a and 7b are covered with a copper plate having a resistance value of about 10 kΩ, and second conductive portions 31 and 31 are formed.

Therefore, when the bracket 11 slides on the sliding contact surface 8a, the current sent from the power source E of the position detecting circuit 23 passes through the conductive sliding contact surface 8a and is grounded. It flows to the existing bracket 11. Since the resistance value of the sliding contact surface 8a varies depending on the region, the current changes according to the resistance value of the sliding contact surface 8a on which the bracket 11 slides. The position detection circuit 23 outputs a signal corresponding to this change to the control system 42. The control system 42 detects the position of the document table 2 from the signal from the position detection circuit 23. In other words, the endless rack 8, the bracket 11, and the position detection circuit 23 constitute the document table position detection device 22 of the present invention for detecting the position of the document table 2.

For example, similarly to the case where the bracket 11 is moved when explaining the operation of the platen driving device 3, the sliding contact surface 8a of the endless rack (the first rack 5, the inner tooth portion 7a on the return side, the When 2 racks 6, inner teeth 7b on the return side, and again to the first rack 5 are slid sequentially, the signal input from the position detection circuit 23 to the control system 42 becomes as shown in FIG.

When the bracket 11 is sliding on the first conductive portion 21 which is the sliding contact surface 8a corresponding to the first rack 5, the resistance of the first conductive portion 21 is very small, so that it is sent from the power source E. Since most of the electric current escapes through the bracket 11, the signal (voltage) input to the control system 42 becomes very small and becomes a low and constant signal of about 0.2V.

Next, when the bracket 11 begins to slide on the second conductive portion 31 which is the sliding contact surface of the internal tooth portion 7a on the return side, the resistance value of the second conductive portion 31 is relatively large. As the distance that slides on the conductive portion 31 increases, the resistance increases and the amount of current that escapes through the bracket 11 decreases. As a result, the signal input to the control system 42 is 0.2
It gradually increases from V and increases to about 3.9 V when it reaches the lower end of the internal tooth portion 7a.

When the bracket 11 begins to slide on the first conductive portion 21 which is the sliding contact surface 8a corresponding to the second rack 6, the bracket 11 flows to the first conductive portion 21 as in the case of the first rack 5 described above. Since most of the current escapes through the bracket 11, the signal input to the control system 42 does not increase from 3.9V when it reaches the lower end of the internal tooth portion 7a on the return side.

The bracket 11 finishes sliding on the first conductive portion 21 of the second rack 6 and starts sliding on the second conductive portion 31 which is the sliding contact surface 8a corresponding to the internal tooth portion 7b on the feed side. Then, the resistance decreases as the distance along which the inner tooth portion 7b slides increases, and the amount of current escaping through the bracket 11 increases, contrary to the previous case. As a result, the signal input to the control system 42 gradually decreases from 3.9V, and the internal tooth portion 7b
When it reaches the upper end, it decreases to about 0.2V.

Therefore, the control system 42 of the copying machine of the present embodiment.
Indicates that the signal from the position detection circuit 23 is 0.2V in advance.
Except for the above or 3.9V or more, the power supply is OF
Even if it is turned off, the main motor is not turned off and the signal from the position detection circuit 23 is 0.2V or less, or 3.9V.
Until the above, it is programmed to drive the main motor.

As a result, the driving of the second electric gear 10 is not stopped while the two-stage gear 10 is positioned at the return-side and feed-side internal teeth 7a and 7b.
The document table 2 is prevented from being locked, and paper jams and the like can be dealt with smoothly.

As described above, the original table lock prevention control by the control system 42 of the copying machine is performed by the first conductive portion 21/2 on which the bracket 11 slides on the outer peripheral surface of the endless rack 8.
The position detecting circuit 23 forms a sliding contact surface 8a including the first and second conductive portions 31 and 31, and the position detecting circuit 23 inputs a signal corresponding to a change in the amount of current escaping through the bracket 11 to the control system 42. .. Therefore, conventionally, the fact that the document table 2 is located on the end side of the copying machine is detected by the switch operating section attached to the endless rack and the turn section detecting switch arranged near the endless rack. Therefore, there is a problem that the number of parts increases and an extra mounting space is required, but this can reduce the number of parts and save space. As a result, a smaller copying machine can be manufactured.

The copying machine according to the present embodiment is configured to detect the case where the document table 2 is located on the end side, and further, an area corresponding to the copy start position in the endless rack 8. It is also conceivable that a conductive member having a different resistance value is provided in and the copy start position is detected based on the signal from the position detection circuit 23.

[0045]

As described above, the position detecting device of the document table according to the present invention connects two rack portions provided in parallel with their tooth surfaces facing each other and the end portions of both rack portions. And an annular endless rack provided with two semi-circular gear parts having inner teeth arranged on a semi-circle, which is connected to the document table and is linearly movable, and a drive which meshes with the endless rack. A side gear and a bracket that supports the drive side gear and slides on the end surface of the endless rack are provided, and a sliding contact surface of the endless rack on which the bracket slides is provided in an area corresponding to both rack portions. A first conductive portion having a predetermined resistance value is provided, while a second conductive portion having a resistance value different from that of the first conductive portion is provided in a region corresponding to both semi-circular gear portions, and further, a bracket and a slide are provided. Electricity between the contact surface Position detecting circuit which emits an electrical signal corresponding to the resistance is a configuration in which is provided.

Therefore, the position of the document table can be detected by the endless rack and the bracket which have been conventionally used. As a result, the number of parts can be reduced and the space can be saved, and the size of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view of a document table position detecting device in a copying machine according to an embodiment of the present invention.

FIG. 2 is a schematic overall configuration diagram of the copying machine.

FIG. 3 is a perspective view of a document table driving device applied to the copying machine.

FIG. 4 is a time chart showing signals output from a position detection circuit in the copying machine.

FIG. 5 is a front view showing a structure around a document table of a copying machine equipped with a conventional document table driving device.

FIG. 6 is a front view of the document table driving device shown in FIG.

FIG. 7 is a perspective view of an endless rack including a conventional document table position detection device.

[Explanation of symbols]

 2 Manuscript table 5 1st rack (rack part) 6 2nd rack (rack part) 7a Return side internal tooth part (semi-circular gear part) 7b Feed side internal tooth part (semi-circular gear part) 8 Endless rack 8a Sliding surface (End face) 21 First conductive part 22 Position detection device for document table 31 Second conductive part 9 Output gear for driving 9 (Drive side gear) 10 Two-step gear (Drive side gear) 11 Bracket 11a Bent part 23 Position detection circuit E Power supply (position detection circuit) R Resistor (position detection circuit)

Claims (1)

[Claims] 1. A pair of parallel teeth 2 with their tooth surfaces facing each other.
And two semi-circular gear parts having inner teeth arranged on a semi-circle and connecting the rack parts and the end parts of the two rack parts together, and being connected to the document table so as to be linearly movable A ring-shaped endless rack, a drive-side gear that meshes with the endless rack, and a bracket that supports the drive-side gear and slides on the end face of the endless rack. The sliding contact surface of the rack is provided with a first conductive portion having a predetermined resistance value in a region corresponding to both rack portions, and a resistance different from the first conductive portion in a region corresponding to both semi-circular gear portions. A position detecting device for a document table, further comprising a second conductive portion having a value, and further a position detecting circuit for emitting an electric signal according to an electric resistance between the bracket and the sliding contact surface. ..