JPH11263484A - Picture image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust sheet carrier speed on a resist roller so that favourable picture image formation is carried out without complicating constitution. SOLUTION: The number of rotation of a paper feeding motor 40 which is a rotational driving source of a resist roller 23, that is, a setting value of exciting time for a stepping motor is changed and sheet carrier speed of the resist roller 23 is adjusted to enter a proper range by carrying out setting value changing input from an outside operating part 36 to a roller driving control part 33 in the case when the sheet carrier speed is not proper speed due to dispersion of the resist roller 23, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which an image is formed by transferring a toner image formed on a photoreceptor to a sheet, and more particularly, to conveying a sheet with respect to a photoreceptor at a proper timing. The present invention relates to a configuration for adjusting a sheet conveyance speed in a registration roller to be adjusted.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system, a sheet conveying speed of a registration roller provided upstream of a photosensitive member with respect to sheet conveying greatly affects image forming performance. Specifically, when a toner image is transferred from a photoconductor to a sheet, if a difference occurs between the sheet conveying speed of the registration roller and the sheet conveying speed of the transfer unit, the difference in the sheet conveying speed causes the registration roller to shift. When a loop occurs on the sheet or the sheet is pulled between the transfer sections, and these phenomena appear remarkably, there is a problem that the formed image is disturbed.

As described above, ideally, it is desirable that the paper transport speed in the transfer section and the registration roller be the same.

Therefore, conventionally, in order to reduce the variation in the sheet conveying speed, the tolerance of the outer diameter of the registration roller is suppressed to the limit that can be processed.

Further, if the paper transport speed of the registration rollers is lower than that of the transfer unit, the paper slips in the transfer unit. Therefore, in the related art, the speed is set in advance so that the paper transport speed of the registration rollers is higher than that of the transfer unit. I have.

[0006] After the paper is fed several tens of thousands of times by the registration roller, the registration roller wears and its outer diameter becomes small. It tends to be slow. Therefore, the paper transport speed of the registration roller is slower than the theoretical value, the transport speed relationship with the transfer unit is reversed, and the paper is pulled by the registration roller, causing an image to be disturbed. Therefore, conventionally, in consideration of wear of the registration rollers after feeding a large number of sheets, it is set in advance so that the speed difference of the sheet conveyance speed becomes large.

However, a loop is easily formed in the sheet, and when the loop of the sheet is increased, a space is formed in the sheet conveying path or a movable portion for absorbing the loop is formed so that the loop can be absorbed. A paper guide plate with a structure was installed.

[0008]

As described above, according to the prior art, increasing the processing accuracy in order to reduce the variation in the diameter of the registration roller increases the manufacturing cost, and also increases the paper cost. The installation of a special paper guide plate for absorbing the loop complicates the related configuration, which also increases the cost and lengthens the entire image forming apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which can solve the above-mentioned conventional problems and can adjust the sheet conveying speed of a registration roller so that a good image can be formed without complicating the structure. To provide.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a photoconductor, a registration roller that conveys a sheet to the photoconductor in a timely manner, and a sheet conveyed from the registration roller. In an image forming apparatus including a transfer unit that transfers a toner image formed on a photoreceptor, the number of rotations of a rotation drive unit that drives the registration roller can be changed according to a variation in a sheet conveyance speed of the registration roller. This configuration eliminates the necessity of performing high-precision processing required for setting the paper transport speed in the manufacture of the registration rollers, and reduces the relationship between the transfer unit and the paper transport speed. By adjusting the number of rotations by the rotation drive unit for each registration roller, the paper transport speed of the registration rollers can be set properly. It can be.

Further, the present invention is characterized in that the number of revolutions in the rotation drive unit can be set by an external operation unit provided in the main body of the image forming apparatus. The speed can be easily set, and the installation and use of a registration roller such as a recycled product can be performed without complicated adjustment.

Further, according to the present invention, a detecting means for measuring a paper transport time is provided on the downstream side of the paper transport in the registration roller, and based on a detection result of the detecting means, a rotation speed of the rotation drive unit is determined. It is characterized by setting, and by this configuration, the actual paper transport time (speed)
Can be set on the basis of the detection result, and the paper conveyance speed at the registration rollers can be set practically and accurately.

Further, according to the present invention, the number of rotations in the rotation drive unit is set in accordance with the number of paper sheets fed, the size of the paper, the type of paper, etc., so that the paper transport speed of the registration roller with respect to the transfer unit is adjusted. It can always be appropriate.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a facsimile apparatus using an electrophotographic recording system for explaining an embodiment of the present invention. Reference numeral denotes an image forming unit built in the apparatus main body 2.

The document reading unit 1 includes an optical document reading device 5
A document feeding unit 6 for feeding a document to the optical document reading device 5, and a document feeding unit 6 for feeding a document from the document feeding unit 6 to the optical document reading device 5.
The document information read by the optical document reading device 5 includes a pair of paper feed rollers 7 and 8 which convey the document to a reading line L at a predetermined speed and discharge the sheet to the outside. Sent through.

The image forming section 3 is of an electrophotographic recording type, and has a belt-shaped photoreceptor 10, a charge removing LED 11 for removing residual charges on the surface of the photoreceptor 10, and a uniform surface of the photoreceptor 10 after the charge removal. A charging charger 12 for charging; a laser optical system 13 for exposing the charged photoconductor 10 based on received information to form a latent image; and a developing unit for developing the latent image formed on the photoconductor 10 with toner 14, a transfer charger 15 for transferring the toner image to the fed paper, and a cleaning unit 16 for removing and collecting residual toner remaining on the photoconductor 10 after the transfer.

The paper P is stored in a paper feed cassette 20,
The sheet is fed to the registration roller 23 by the pickup roller 21 and the conveyance roller 22, and is fed to the transfer charger 15 by the registration roller 23 at the same time as the movement of the toner image formed on the photoconductor 10. The paper P after the transfer is fixed to a fixing unit 27 including heating / pressing rollers 25 and 26.
Then, the image is fixed, and the sheet is discharged to the outside by a sheet discharging roller 28.

A sheet detection sensor 30 for detecting the presence or absence of the sheet P is provided on the downstream side of the sheet conveyance path near the registration roller 23.
Is installed. The detection (on-off) signal from the paper detection sensor 30 is transmitted to the CPU 31 as shown in FIG.
The paper length and paper transport time are determined by the transport time calculation unit 32 of the CPU 31 according to the time from the passage of the leading edge of the paper P (detection of paper presence) to the passage of the trailing edge of the paper P (detection of absence of paper). Calculate. The setting information relating to the paper transport time is input to a roller drive control unit 33 of the CPU 31, and a control signal is further output to a motor drive unit 34 of a paper feed motor 40 (to be described later) that rotationally drives the registration rollers 23 and the like. For the roller drive control unit 33, a key group for setting various modes or a display for displaying an operation state is provided on the upper wall of the upper body 35 which is provided on the upper part of the apparatus body 2 in this example. Settings can also be input from an external operation unit 36 provided with a unit or the like.

FIG. 2 is an explanatory view showing a schematic configuration of a gear group, motors, and a control system of a mechanical drive system in the apparatus shown in FIG.
The rotation driving force of 0 is applied to the pickup roller 21 via a first rotation transmission system 41 including a gear, a pulley, a belt, and the like.
It is transmitted to the registration rollers 23 and the like. Further, the rotational driving force of the main motor 42 is transmitted to the driving roller 44 of the photoconductor 10 and the driving roller 45 of the fixing unit 27 via a second rotation transmission system 43 including a gear, a pulley, a belt, and the like. Is done. Further, the rotational driving force of the document conveying motor 46 is
Third rotation transmission system 47 including gears, pulleys, belts, etc.
Is transmitted to the paper feed roller pairs 7, 8 and the like.

Due to the above-described configuration, by changing the number of revolutions of the sheet feeding motor 40, that is, the set value of the excitation time for the stepping motor, the sheet conveying speed of the registration roller 23 which is a feature of the present invention described below is changed. Can be. The setting and change of the excitation time are performed by the external operation unit 36.
By inputting the set value to the roller drive control unit 33 from, it can be easily performed.

Further, the setting of the excitation time can be performed by using the paper detection sensor 30. That is, in order to adjust the paper conveyance speed of the registration roller 23 to a specified speed, first, a paper having a predetermined reference length is passed through a normal conveyance path, and the paper is moved to the vicinity of the registration roller 23. Of the sheet is detected by the sheet detection sensor 30 of FIG. Based on the on-off time of the paper detection sensor 30, the transport time calculation unit 32 causes the external operation unit 36 to display whether or not the transport time is appropriate for the paper length.

Then, the user confirms whether the transport time (speed) is fast (fast) or slow on the display of the external operation unit 36, and as described above, the rotation speed of the sheet feeding motor 40, that is, excitation of the stepping motor. The time is reset for the roller drive control unit 33. Then, after the resetting, the sheet of the reference length is again passed through the normal conveyance path, and the sheet detection sensor 30 detects the end of the sheet. This display confirmation operation and setting operation are repeatedly performed until the transport time falls within the specified range.

If the relationship between the reference length of a sheet and the transport time (speed) of the sheet is set in advance and stored in a memory such as the CPU 31 as a data table, the CPU 3
1, the paper transport time of the registration rollers 23 can be automatically set in the roller drive control unit 33 by referring to the data table based on the detection result of the paper detection sensor 30.

As described above, since the actual transport time for the paper by the registration roller 23 can be adjusted, the paper is transported without variation.

The paper transport time of the registration roller 23 is adjusted when the number of papers fed (operating time of the apparatus) reaches a predetermined number or every time the paper size and paper type are different. The paper size is determined by a size detection unit provided in the paper cassette 20. The type of paper is set by a user or a service person by using an input unit provided in the external operation unit 36. However, since ordinary users rarely change the type of paper, if the paper transport time is set once when the apparatus is installed, there is almost no need to reset it again.

As described above, according to the present embodiment, it is not necessary to perform high-precision processing required for setting the sheet conveyance speed when manufacturing the registration roller 23, and the transfer roller 15 and the transfer charger 15 are not required. By setting the roller drive control unit 33 to adjust the rotation speed of the sheet feeding motor 40 for each registration roller 23 in relation to the sheet conveyance speed, the paper Since the transport speed can be set appropriately, the component processing cost can be reduced.

Further, by adjusting and setting the recycling (reuse) of the commercialized expensive registration roller 23 as described above, the registration roller 23 can be easily processed without special processing and processing. Becomes possible.

Further, by making the setting based on the transport time of the paper being actually transported detected by the on-off time of the paper detection sensor 30, the paper transport speed of the registration roller 23 can be practically and reliably ensured. Settings can be made, and automatic settings can be made.

Further, when the number of fed sheets exceeds 10,000, for example, the registration rollers 23 are worn out, the outer diameter becomes small, and the conveyance deviation is reduced so as to be slower than the initial sheet conveyance speed. Therefore, by performing the setting when the number of fed sheets reaches a predetermined number, the sheet conveying speed of the registration roller 23 with respect to the transfer charger 15 can always be maintained in an appropriate state. .

[0031]

As described above, according to the present invention,
In the manufacture of the registration rollers, it is no longer necessary to perform the high-precision processing required for setting the paper conveyance speed, and in relation to the paper conveyance speed with the transfer unit, the rotation driving unit is used for each registration roller. By adjusting the number of revolutions, the paper transport speed of the registration rollers can be set appropriately.

Further, the paper transport speed of the registration rollers can be easily set by an external operation unit provided in the image forming apparatus main body, and another registration roller such as a recycled product can be installed and used. It can be performed without complicated adjustment.

Further, a detecting means for measuring the paper transport time is installed downstream of the paper transport in the registration roller, and the setting is performed based on the detection result of the actual paper transport time (speed) by this detecting means. Because you can
Practical and accurate setting of the paper transport speed at the registration roller is enabled.

Further, by performing the above-described setting in accordance with the number of sheets fed, the size of the sheet, the type of the sheet, etc., the sheet conveying speed of the registration roller with respect to the transfer section can always be made appropriate.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a facsimile apparatus using an electrophotographic recording method for describing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of a gear group, motors, and a light control system of a mechanical drive system in the apparatus of FIG. 1;

[Explanation of symbols]

 3 Image Forming Unit 10 Photoconductor 15 Transfer Charger 23 Registration Roller 30 Paper Detection Sensor 31 CPU 32 Transport Time Calculator 33 Roller Drive Controller 34 Feed Motor Drive 36 External Operation Unit 40 Feed Motor 41, 42, 43 Rotation Transmission system

Claims (4)

[Claims] A photoconductor; a registration roller configured to convey a sheet to the photoconductor in a timely manner; and a transfer unit configured to transfer a toner image formed on the photoconductor to the sheet conveyed from the registration roller. An image forming apparatus according to claim 1, wherein the number of rotations of a rotation drive unit for rotating the registration roller can be changed in accordance with a variation in the sheet conveyance speed of the registration roller. 2. The image forming apparatus according to claim 1, wherein the number of rotations of said rotation drive unit can be set by an external operation unit provided in the image forming apparatus main body. 3. A detecting means for measuring a sheet conveying time on the downstream side of the sheet conveying in the registration roller, wherein the number of rotations in the rotation drive unit is set based on a detection result of the detecting means. Claim 1 characterized by the following:
The image forming apparatus as described in the above. 4. The image forming apparatus according to claim 1, wherein the number of rotations in the rotation drive unit is set in accordance with the number of sheets fed, the size of paper, the type of paper, and the like. .