JP2974333B2 - Paper supply device for image processing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper supply apparatus for an image processing apparatus, and more particularly, to a paper supply apparatus for supplying paper to an image forming unit of the image processing apparatus.

[Conventional technology]

For example, in a copying machine having a photosensitive drum on which an image is formed on its surface, a registration roller is conventionally provided in order to align the leading end of the image on the drum with the leading end of a sheet onto which the image is transferred. This registration roller temporarily stops the paper before the drum, and feeds the paper in synchronization with the image on the drum.

Paper is fed to the registration roller by, for example, a transport mechanism from a paper feed cassette. At this time, in a high-speed copying machine, the paper hits the registration roller more strongly, and at that time, the roller rotates slightly, so that the timing of the image on the drum and the paper can be accurately matched. Disappears.

FIG. 7 shows the result of actually measuring the rotation speed of the registration roller using an encoder. In FIG. 7, the horizontal axis represents time, and the vertical axis represents encoder output. As is apparent from FIG. 7, a peak occurs at the time when the sheet hits the registration roller (part A), indicating that the registration roller has been rotated by the conveyed sheet.

To prevent such a problem, Japanese Patent Application Laid-Open No. 60-2580
In No. 32, a device (friction member or brake) that suppresses the rotation of the roller by frictional force is provided.

[Problems to be solved by the invention]

In the conventional configuration, the start-up timing of the device for suppressing unnecessary rotation is not taken into consideration, and the driving force to stop the rotation before the driving force to the roller is completely cut off acts on the roller. And frictional force compete with each other. As a result, the load on the mechanism for exerting the frictional force and the driving force increases, and their durability decreases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a paper supply apparatus for an image processing apparatus capable of improving durability by preventing a driving unit and a holding unit of a registration roller from competing with each other and accurately supplying a sheet with the registration roller. It is in.

[Means for solving the problem]

The paper supply device according to the present invention is a device for supplying paper to an image forming unit of an image processing apparatus, and includes a pair of rollers that can approach and separate from each other, and is provided to the image forming unit at a predetermined timing. A registration roller for supplying the sheet, a conveying unit for conveying the sheet to the registration roller, a driving unit for rotating the registration roller, and a pair of rollers constituting the registration roller pressed against each other to register the sheet. Holding means for inhibiting the rotation of the roller, first control means for controlling the driving means to rotate the registration roller for a predetermined period, and inhibition of the rotation of the registration roller only while the registration roller is not driven by the driving means And a second control means for controlling the holding means so as to perform the control.

[Action]

In the sheet supply device according to the present invention, the sheet is conveyed to the registration roller side by the conveyance unit, and the leading end of the sheet strikes the registration roller. At this time, the registration roller is not driven, and the holding unit holds the registration roller based on the control by the second control unit. Therefore, even if the paper hits the registration rollers,
The registration roller does not easily rotate.

Next, the registration roller is rotationally driven by the driving means so as to supply the sheet to the image processing mechanism at a predetermined timing. This rotation drive is performed based on control by the first control means.

Here, the second control unit controls the holding unit so as to hold the registration roller only while the registration roller is not driven by the driving unit. As a result, the driving means and the holding means do not compete with each other, and the durability of the device is improved. Moreover, since the holding means for holding the registration roller so as not to rotate is provided, unnecessary rotation of the registration roller can be suppressed, and the paper can be supplied accurately.

At this time, the rotation can be stopped simply by pressing the pair of rollers constituting the registration roller against each other, so that the configuration is simplified.

〔Example〕

FIG. 1 shows a copying machine according to an embodiment of the present invention.

In FIG. 1, a document table 2 is fixed on an upper surface of a copying machine main body 1, and an automatic document feeder 3 is arranged on the document table 2. Paper feed cassettes 4 and 5 are detachably mounted on the right side of the copying machine body 1 in the figure. On the left side of the main body 1 of the copying machine, a paper discharge tray 6 for discharging copied paper is mounted.

Inside the copier body 1, an exposure device 7 for reading an original is provided above the copier body 1. The exposure device 7 includes a light source, a mirror, a lens unit, and the like. A photosensitive drum 8 on the surface of which an electrostatic latent image is formed is arranged at the center of the copying machine body 1.
Around the photosensitive drum 8, a charging device 9, a developing device 10,
A transfer device 11, a paper separating device 12, and a cleaning device 13 are sequentially arranged.

A paper feed path 14 for feeding paper is provided between the paper feed cassettes 4 and 5 and an image forming unit including the photosensitive drum 8 and the like. Further, between the image forming section and the paper discharge tray 6, a paper discharge conveyance path 15, a fixing device 16 for fixing a transferred image on the paper, and a discharge roller 17 are arranged.

The upstream portion of the paper feed path 14 is branched, and is connected to the paper feed cassette 4 and the paper feed cassette 5 at its upstream end. A pair of upper and lower transport rollers 20 is disposed at the confluence of the sheet transport path 14. A pair of upper and lower guide plates 21 for guiding the sheet when the sheet is temporarily stopped is disposed downstream of the transport roller 20. On the guide plate 21, a paper sensor 22 composed of a photo interrupter or the like for detecting the presence or absence of a paper is arranged. On the downstream side of the guide plate 21, just before the image forming unit, a registration roller 23 is disposed.

FIG. 6 is a longitudinal sectional view of the registration roller 23. As shown in FIG. 6, the registration roller 23 is mainly constituted by a pair of upper and lower rollers 24 and 25 which are in pressure contact with each other. The roller 24 is rotatably supported by a wall plate 26 on the copying machine main body side. The rotation shaft 27 of the lower roller 25 is also rotatably supported by the wall plate 26, and its tip end is
It protrudes from 26 and is connected to a drive mechanism 28.

In the driving mechanism 28, a sprocket 30 to which a driving force is transmitted from a driving source (not shown) is rotatably supported by a rotating shaft 27. On the right side of the sprocket 30, the rotating shaft 27
A friction plate 31 rotatably supported is disposed at the center. The friction plate 31 and the sprocket 30 are connected by an elastic plate 32, and the friction plate 31 is constantly urged toward the sprocket 30 by the elastic plate 32. The clutch plate 33 disposed concentrically and opposed to the friction plate 31 is integrally supported by the rotating shaft 27. An electromagnetic actuator 34 is rotatably fitted to the boss of the clutch plate 33. The electromagnetic actuator 34 has a wall plate 26
The rotation is stopped by a stopper 35 fixed to the arm.

A frictional force applying mechanism 36 is disposed at the tip of the rotating shaft 27. A cylindrical member 37 is fixed to a tip of the frictional force applying mechanism 36. On the electromagnetic actuator 34 side of the cylindrical member 37,
A friction plate 38 is arranged, and the friction plate 38 is elastically held by a cylindrical member 37 via an elastic plate 41. The friction plate
38 is constantly urged toward the cylindrical member 37 by the elastic plate 41. A clutch plate 39 is arranged closer to the electromagnetic actuator 34 than the friction plate 38 is. The clutch plate 39 is rotatably supported on the rotating shaft 27 via a bearing. Another electromagnetic actuator 40 is arranged on the boss extending from the clutch plate 39 toward the electromagnetic actuator 34. The electromagnetic actuator 40 is integrally fixed to the clutch plate 39 and has a stopper 35.
It is detented by.

The above-described copying machine includes a control unit 50 as shown in FIG. The control unit 50 includes a microcomputer including a CPU, a RAM, a ROM, and the like. The control unit 50 is connected to a print key 51, a paper sensor 22, and other input units of a key panel (not shown) arranged on the upper surface of the copying machine main body 1 (FIG. 1). The control unit 50 is connected to the drive-side electromagnetic actuator 34, the brake-side electromagnetic actuator 40, the drive unit of the transport roller 20, and other output units shown in FIG.

Next, the operation of the above embodiment will be described with reference to the control flowcharts shown in FIGS. 4A and 4B.

When a main switch (not shown) is turned on, a program is started, and in step S1, initial settings such as setting the number of copies to 1 and setting the fixing device 16 to a predetermined temperature are performed.

Next, in step S2, it is determined whether the print key 51 has been pressed. If the print key 51 has not been pressed, the process proceeds to step S3. In step S3, it is determined whether a key other than the print key 51 has been input. If those keys have not been input, the process returns to step S2.
That is, in steps S2 and S3, an instruction by a key input is waited. When a key other than the print key 51 is pressed, the process proceeds from step S3 to step S4. In step S4, various processes corresponding to the input keys are performed,
When the process ends, the process returns to step S2.

Here, it is assumed that the print key 51 is pressed by the operator. Thereby, the program shifts from step S2 to step S5, and the copy subroutine is executed. In this copy subroutine, a sheet is conveyed from the selected paper feed cassette 4 or 5 to the image forming unit side, and the exposing device 7 scans a document on the document table 2. An electrostatic latent image is formed on the photosensitive drum 8 based on image information obtained from the document, and the electrostatic latent image is developed by the developing device 10. The developed image is transferred onto the supplied paper
Transcribed by 11. The sheet on which the image has been transferred is subjected to a fixing process by the fixing device 16 and then discharged onto the sheet discharge tray 6. If the copying operation is repeated the number of times corresponding to the designated number of copies and the entire copying subroutine is executed, the program returns to the main routine composed of steps S2 and S3.

Next, the control in the paper feed path 14 executed in the above-described copy subroutine will be described with reference to FIG. 4B.

First, in step S6, the cam 63 is rotated by controlling the solenoid mechanism 65, and the pressing force between the roller 25 and the roller 24 is increased. As a result, the two rollers 24 and 25 of the registration roller 23 are pressed against each other by the rotation of the cam 63,
The rotation of the registration roller 23 is prohibited.

Next, in step S7, the selected paper feed cassette 4
Alternatively, a predetermined sheet from 5 is supplied to the paper feed path 14. At this time, the transport roller 20 is also driven. In step S8, it is determined whether or not the leading edge of the sheet conveyed to the registration roller 23 side by the conveying roller 20 is detected by the sheet sensor 22. If the leading edge of the sheet is detected, the process proceeds to step S9. When the sheet is conveyed by the conveyance roller 20, the leading end of the sheet abuts on the registration roller 23, but the registration roller 23 is held by the frictional force applying mechanism 60, so that the contact causes the registration roller 23 to rotate. It will not be lost.

In step S9, when the leading end of the sheet comes into contact with the registration roller 23 and a period in which a predetermined bending can be given to the sheet has elapsed, the transport roller 20 is stopped. The inclination of the sheet is corrected by the deflection applied at this time, and the leading end of the sheet uniformly contacts the registration roller 23.

In step S10, the cam 63 is rotated to reduce the pressing force of the roller 25 against the roller 24 so that the registration roller can rotate smoothly.

In step S11, the driving force from the driving mechanism 28 is transmitted to the rotation shaft of the registration roller after a predetermined time has elapsed after the holding of the registration roller is released. As a result, the rollers 24 and 25 rotate, and the sheet is supplied to the image forming unit side by the registration roller 23 at a predetermined timing. If a predetermined time elapses after the paper sensor 22 detects the trailing edge of the paper, it can be considered that the paper has completely moved to the image forming unit side.
In S12, the registration roller 13 is stopped.

The transport operation of the paper in the paper transport path 14 is performed for each paper supply according to the control of steps S6 to S12 shown in FIG. 4B. FIG. 4B shows only the control in the paper feed path 14, and the copy subroutine includes various controls such as control of the exposure device 7 and control of the fixing device 16.

FIG. 5 shows the results of an experiment in which an encoder for detecting the rotation speed was attached to the registration roller 23. Fifth
In the figure, the horizontal axis is time, and the vertical axis is output. X represents the change in the voltage applied to the electromagnetic actuator 40, and Y represents the electromagnetic actuator 34.
, And Z indicates the output voltage from the encoder corresponding to the rotation speed of the registration roller 23. In addition, in X, the upper side is a clutch OFF state, and the lower side is a clutch ON state. In Y, the upper side shows the clutch ON state and the lower side shows the clutch OFF state.

The outline of the sheet supply operation will be described with reference to FIG. In a state where the driving force is not transmitted to the rotating shaft 27, the frictional force applying mechanism 36 is driven (p point), and the registration roller 23 is held. The sheet is supplied while the registration roller 23 is held by the frictional force applying mechanism 36, and the leading end of the sheet strikes the registration roller 23. However, the registration roller 23 does not rotate due to the contact of the sheet (part A). ). When the holding of the registration roller 23 by the frictional force applying mechanism 36 is released (point r), the driving force from the sprocket 30 is not transmitted to the rotating shaft 27. After the release of the holding of the registration roller 23 by the frictional force applying mechanism 36 is completed, the electromagnetic actuator 34 is driven (s
Point), the rotational driving force is transmitted to the registration roller 23. When the conveyance of the sheet is completed by the registration roller 23 (point t), the driving force from the sprocket 30 is not transmitted to the registration roller 23 side, and the registration roller 23 stops. After a lapse of a predetermined time, the frictional force applying mechanism 36 is driven to hold the registration roller 23 again (point p).

FIG. 2 shows an example of the frictional force applying mechanism 60. In FIG. 2, the lower roller 25 of the registration roller 23 is
As shown in the figure, it is movable vertically and rotatably supported. A cylindrical cam follower 61 is provided on the rotation shaft 27 of the roller 25.
Are fixed concentrically. Below the lower roller 25,
The rotating shaft 62 of the frictional force applying mechanism 60 is arranged in parallel.
A cam 63 is fixed to the rotating shaft 62 at a portion facing the cam follower 61. The rotating shaft 62 is provided with a spring clutch 64. The spring clutch 64 is turned on by a solenoid mechanism 65 being driven.
It is turned off. A driving force is transmitted to an input side gear of the spring clutch from a driving unit (not shown). In this embodiment, a drive mechanism 28 having a clutch is provided on the upper roller 24.

In the embodiment shown in FIG. 2, by controlling the solenoid mechanism 65, the cam 63 is rotated so that the roller 25
Change the pressing force against 24. If the pressing force by the roller 25 increases, the registration roller 23 becomes difficult to rotate, and does not rotate even if the sheet abuts. When the resist roller 23 is driven to rotate, the roller 24 is
Is controlled so as to reduce the pressure contact force with respect to, and to smoothly rotate the registration roller 23.

〔The invention's effect〕

In the paper supply device according to the present invention, the driving unit and the holding unit do not compete with each other, and the durability of the device is improved. Then, the pair of rollers constituting the registration roller are pressed against each other to inhibit the rotation of the registration roller, thereby simplifying the configuration.

[Brief description of the drawings]

1 is a schematic longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a perspective partial view of the embodiment, FIG. 3 is a block diagram of a control unit,
4A and 4B are control flowcharts, FIG. 5 is an operation waveform diagram showing an experimental result in a control state, FIG. 6 is a vertical cross-sectional reference diagram near a registration roller, and FIG. 7 is an operation waveform diagram of a conventional example. It is. 14: paper feed path, 20: transport roller, 23: registration roller, 28: drive mechanism, 36, 60 ... frictional force applying mechanism, 5
0 ... Control unit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-93153 (JP, A) JP-A-61-23043 (JP, A) JP-A-56-59253 (JP, A) JP-A 60-93253 258032 (JP, A) Fully open 1987-77157 (JP, U) Fully open, 62-59636 (JP, U) Fully open, 1987-203145 (JP, U) Fully open, 60-60544 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 15/00 510-534 B65H 9/14 B41J 13/00-13/02

Claims (1)

(57) [Claims] An image processing apparatus paper supply device for supplying paper to an image forming section of an image processing apparatus, comprising: a pair of rollers which can approach and separate from each other; A registration roller for supplying a sheet at a predetermined timing; a conveying unit for conveying the sheet to the registration roller; a driving unit for rotating the registration roller; and a pair of rollers constituting the registration roller Holding means for pressing the registration rollers against each other to inhibit rotation of the registration roller; first control means for controlling the driving means to rotate the registration roller for a predetermined period; and wherein the registration roller is driven by the driving means. A second control means for controlling the holding means so as to prohibit the rotation of the registration roller only during the period when the image forming apparatus is not in use. Paper feeder for scientific equipment.