JPH0293665A - Image output device - Google Patents

Abstract

PURPOSE:To always keep a distance between a photosensitive drum mounted in a rocking frame and a transferring and conveying drum constant and to improve workability in the case of repair and maintenance by allowing the rocking frame to freely rock with respect to a main frame. CONSTITUTION:A rocking frame unit 20 is supported in the main frame 24 with a pivot axis 21, a cam 22 and a cam follower 23. A motor 29 rotates the cam 22 with a signal in accordance with a distance between the paper conveying and transferring drum 3 and the photosensitive drum 12 and, with the action of the cam 22, the cam follower 23 provided in the rocking frame unit 20 follows the cam 22, so that the rocking and sliding frame units 20 and 25 can be rocked. With such a correcting operation, the distance between the photosensitive drum 12 and the paper conveying and transferring drum 3 can always be kept constant with variance equal to or under a specified value. Thus, the optimum transfer condition can always be secured and excellent transfer can be performed, then the maintenance workability, etc., can be facili tated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image output device such as an electronic copying machine, and in particular,
The present invention relates to an image output device using a photosensitive drum and a transfer conveyance drum that is pressed against the photosensitive drum.

[Conventional technology]

For example, in a color electronic copying machine, it is necessary to multiple-transfer images made of a plurality of color materials, such as color toners, onto a sheet of paper.

As a means for realizing this multiple transfer, there is a method in which a plurality of image forming units corresponding to each color are arranged around a transfer conveyance drum. Each image forming unit has a photosensitive drum and a developing device.

A cleaner and the like are arranged, and toner images of respective colors are formed on the photosensitive drums in each image forming unit. Each photosensitive drum is brought into pressure contact with a common transfer conveyance drum, so that the toner images on each photosensitive drum are multiple-transferred onto the transfer conveyance drum. As a result, a color image is obtained on the transfer and conveyance drum, which is transferred to paper and then fixed to obtain a color copy.

[Problem to be solved by the invention]

In this way, in an image output device that performs multiple transfer by pressing each photosensitive drum against the transfer/conveyance drum, it is necessary to always maintain a constant distance between the photosensitive drum and the transfer/conveyance drum.

However, due to manufacturing precision or changes over time,
It is difficult to maintain the above distance uniformly. For this reason, there have been problems in that the image is not sufficiently transferred from the photosensitive drum to the transfer/conveyance drum, or the transfer position from each photosensitive drum to the transfer/conveyance drum is shifted, resulting in color misregistration.

Furthermore, when repairing or maintaining functional parts such as the photosensitive drum, developer, and cleaner installed in each image forming unit, the entire image forming unit must be removed from the main body of the image output device, resulting in poor work efficiency. There was also the problem.

The present invention was devised to solve the above-mentioned problems, and aims to keep the distance between the photosensitive drum and the transfer conveyance drum constant at all times, and to improve workability during repair and maintenance. purpose.

[Means to solve the problem]

In order to achieve the above object, the image output device of the present invention has a swinging frame pivotally attached to a main frame on which a transfer withdrawal drum is pivotally supported, and a sliding frame containing an image forming means including a photosensitive drum is fixed to the swinging frame. The oscillating frame is attached to the movable frame so as to extend in the axial direction of the transfer conveyance drum, and the oscillating frame is further oscillated so that the distance between the transfer conveyance drum and the photosensitive drum is maintained substantially constant. It is characterized by the provision of a swing support mechanism.

As the swing support mechanism, a cam provided on the main frame and a cam follower provided on the swing frame and engaged with the cam can be used.

Further, as the swing support mechanism, a tracking roll that is provided coaxially with the photosensitive drum and presses against the circumferential surface of the transfer conveyance drum can also be used.

[Effect]

In the present invention, the swing frame is swingable relative to the main frame. Therefore, the distance between the photosensitive drum of the sliding frame attached to the swinging frame and the transfer conveyance drum can be adjusted.

Therefore, by swinging the swing frame using a cam mechanism, tracking roll, etc., the distance between the photosensitive drum and the transfer conveyance drum can be optimized.

〔Example〕

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, features of the present invention will be specifically described based on examples with reference to the drawings.

FIG. 1 shows an overall view of an image output device according to an embodiment of the present invention.

In the figure, 1 indicates a paper feed tray, and this paper feed tray 1
The paper a accommodated in the image output device is sent out by the feed roll 2 into the inside of the image output device.

A paper transport transfer drum 3 that rotates counterclockwise in the drawing is arranged in the center of the image output device, and around this paper transport transfer drum 3 there are four drums for copying color images. An image forming unit 4°5.6.7 is provided. Further, the paper transport transfer drum 3 is provided with a gripper (not shown) that grips the leading edge of the paper a.

A sheet or mesh made of an insulating material is pasted on the paper transport transfer drum 3, and an electric charge is applied to this sheet or mesh in advance by a corotron 8.

Then, when an actuator (not shown) provided near the gripper of the paper conveyance transfer drum 3 reaches the reference sensor 10, the registration roller 9 starts rotating based on the output of the reference sensor 1O and feeds out the paper. At this time, the gripper is opened by being driven by a cam (not shown), but the position, shape, etc. of the cam are adjusted so that it can grip paper a in a timely manner when paper a is sent. There is.

Since the sheet or mesh is electrically charged, the paper withdrawal transfer drum 3 attracts the paper a sent from the registration rollers 9 and sequentially conveys it to each transfer section of each image forming unit 4.5.6.7. do.

Then, at each transfer section of each image forming unit) 4, 5, 6, 7, the toner images on the photosensitive drum 12 are multiple-transferred onto the paper a by the transfer corotron 11.

When the leading edge of paper a reaches the peeling corotron 13, the gripper is again driven by another cam (not shown) to open and release paper a, and at the same time the electrostatic adsorption force of paper a on the sheet or mesh increases. The sheet a is weakened by the peeling corotron 13 and is peeled off from the sheet transport transfer drum 3, passes through the fixing device 14, and is discharged onto the sheet discharge tray 15.

Here, the image forming operations of the four image forming units) 4, 5, 6, and 7 will be briefly explained with reference to FIG. Note that since each unit has the same configuration, a common explanation will be given below.

In the figure, 16 indicates an RO3 (raster output scanner) equipped with a rotating polygon mirror, and this RO316 scans the photosensitive drum 12 with light such as a laser.

At this time, by turning on and off light from a laser or the like in accordance with an image signal stored in a memory, etc., the charger 1 is
7, a latent image is formed on the photosensitive drum 12 which is charged. This latent image is developed by the developing unit 18,
A toner image is formed on the photosensitive drum 12. Furthermore, this toner image is transferred onto paper a by the transfer corotron 11.

Residual toner left on the photosensitive drum 12 is scraped off by a cleaning device 19 and discharged to the outside.

Next, details of the mounting structure of the image forming units 4.5 and 6.7 will be explained with reference to FIGS. 2 and 3.

In the figure, reference numeral 20 denotes a swing frame unit 20 for supporting the image forming unit in a swingable state with respect to the main frame 24 of the image output device, and this swing frame unit 20 is connected to a pivot shaft 21. (See Figure 1)
, is supported by the main frame 24 by a cam 22 and a cam follower 23. Note that the paper conveyance transfer drum 3
is pivotally supported by the main frame 24.

Further, a sliding frame unit 25 is supported by positioning pins 26 with respect to the swinging frame unit 20.
Moreover, it is supported by a pair of slide rails 27. Therefore, the sliding frame unit 25 can be pulled out from the swinging frame unit 20 toward the front in FIG. 2, and as a result, it can be pulled out of the main frame 24.

The cleaning device 19. Charger 17. Developing unit 18. A photosensitive drum 12 and a drive motor 28 for these devices are provided.

When the sliding frame unit 25 is positioned within the swinging frame unit 20 with the positioning pin 26, the swinging frame unit 20 and the sliding frame unit 25 are integrated, and as described below, ,
By rotating the cam 22, it can swing about the pivot shaft 21 as a fulcrum.

A cam 22 that swings the swinging frame unit 20 is fixed to a camshaft 30, and this camshaft 30 is connected to the main frame 2.
4 is rotatably supported.

The cam 22 has a long groove 22 in the circumferential direction as shown in FIG.
The radius of this long groove 22a changes slightly depending on the angle, for example, it changes by about 300 μm with a rotation of about 300 degrees. In addition, the cam follower 23 is
It is composed of a right triangular support plate 23a fixed near the free end of the swing frame unit 20, and a pin 23b planted at the tip of this support 1 & 23H, and this pin 23b is inserted into the long groove 22a. engaged.

Therefore, when the cam 22 is rotated, the pin 23b of the cam follower 23, which is engaged with the long groove 22a, moves slightly in the radial direction of the paper transport transfer drum 30, and the swinging seven-frame unit 20 uses the pivot shaft 21 as a fulcrum. swaying as
The photosensitive drum 12 has a distance of about 300 mm relative to the paper transport transfer drum 3.
Swings up and down by μm.

This swing motion is driven by a motor 29 fixed to the main frame 24. That is, as shown in FIG. 4, a displacement sensor 41 installed in the swing frame unit 20 measures the distance between the paper transport transfer drum 3 and the photosensitive drum 12 in the transfer area, and the A/D converter 4
After converting it into a digital signal by step 2, a signal is sent to the motor controller 43 to make the distance constant.

A motor driver 44 rotates the motor 29 in response to a signal from the motor controller 43. The motor 29 rotates the cam 22 in response to a signal corresponding to the distance between the paper transport transfer drum 3 and the photosensitive drum 12. By this operation, the cam follower 23 provided in the swinging frame unit 20 follows the cam 22, and the swinging and sliding frame unit 20.25 can be swung.

Through this correction operation, the distance between the photosensitive drum 12 and the paper transport transfer drum 3 could always be kept constant with a variation of 60 μm or less.

In this embodiment, a 5-phase stepping motor is used as the motor 29 to adjust the distance with an accuracy of 0.5 μm per step, but a DC servo motor is used to continuously adjust the distance. It's okay.

Further, in this embodiment, the time for one revolution of the paper transport transfer drum 3 is divided into 36 parts, and a signal is sent to the motor 29 to correct the distance between the photosensitive drum 12 and the paper transport transfer drum 3 for each division. sending. In general, the smaller the number of divisions, the better; however, if the number of divisions is too small, the motor controller 43 for making the motor 29 follow the motor becomes complicated, leading to an increase in cost. Therefore, an appropriate number of divisions may be selected based on the balance between correction accuracy and cost.

The cam 22 also has the role of separating the photosensitive drum 12 from the paper transport transfer drum 3 when the sliding frame unit 25 is pulled out of the main frame 24.

That is, the radius of the long groove 22H formed in the cam 22 is
Since the long groove 22a suddenly becomes smaller at one end 22b, by turning this cam 22 all the way, the rocking,
The sliding frame unit) 20.25 can be held at a distance of approximately 3 mm from the sheet transport transfer drum 3 in that position. Therefore, the sliding frame unit 25 can be pulled out of the main frame 24 without resistance. This operation can be performed by a lever 31 attached to the camshaft 30.

In the above embodiment, the sliding frame unit 25 is supported by the swinging frame unit 20 by the positioning pin 26, and the swinging frame unit 20 is supported by the main frame 24 by the pivot shaft 21 and the cam follower 23. There is.

However, the structure is not limited to this, and as shown in FIG. 5, the sliding frame unit 25 is supported by the swinging frame unit 20 with positioning pins 26 (see FIG. 2), Kabibot shaft 21 (
(see FIG. 2), the photoreceptor shaft 3 is supported by the main frame 24, and is supported by the sliding frame unit 25.
The structure may be such that the swinging/sliding frame units 20 and 25 are supported by the tracking roll 33 provided on the paper transport transfer drum 3 coming into contact with the paper transport transfer drum 3.

In this structure, when the paper transport transfer drum 3 rotates, the tracking roll 33 also rotates and swings around the pivot shaft 21 to follow the paper transport transfer drum 3. At this time, in order to prevent excessive load torque from being applied to the paper transport transfer drum 3, the swing frame unit 20 is pulled up by a counterbalance spring 34 (see FIG. 1). In addition, stopper 3
5 prevents the swing frame unit 20 from falling.

As mentioned above, in this embodiment, the functional devices necessary for electrophotographic copying are mounted on the sliding frame unit 25 that can be pulled out, so that it can be repaired.

During maintenance, the sliding frame unit 25 can be pulled out to perform the work, improving work efficiency. Furthermore, since the sliding frame unit 25 itself is supported by the swinging frame unit 20 that is swingable with respect to the main frame 24, the swinging frame unit 20 and the sliding frame unit 25 as a whole are connected to the pivot shaft 21. It is supported by the cam 22 and the tracking roll 33, and can freely swing about the pivot shaft 21. Therefore, it is possible to arbitrarily adjust the distance between the transfer and conveyance drum 3 and the photosensitive drum 12.

〔Effect of the invention〕

As explained above, according to the present invention, the sliding frame containing the image forming means is attached to the swinging frame so that it can be pulled out, and the swinging frame is made swingable relative to the main frame. Therefore, by controlling the swinging state of the swinging frame, the distance between the photosensitive drum and the paper transport transfer drum can be adjusted. Therefore, the distance between the photosensitive drum and the paper transport transfer drum can always be kept constant. As a result, even if, for example, there are variations or changes in the dimensions of the paper transport transfer drum, optimum transfer conditions can always be ensured and good transfer can be performed. Further, since the sliding frame containing the image forming means including the photosensitive drum that is pressed against the transfer conveyance drum is detachably attached to the swing frame, maintenance work and the like are facilitated.

[Brief explanation of drawings]

FIG. 1 is an overall view of an image output device according to an embodiment of the present invention, FIG. 2 is a side view of a main part of an image forming frame unit used in the image output device, and FIG. 3 is a sectional view of the image output device. FIG. 4 is a block diagram of a distance correction circuit, and FIG. 5 is a sectional view of an image output device showing another embodiment of the present invention. l: Paper feed tray 2: Feed roll 3: Paper transport transfer drum 4, 5.6.7: Image forming frame unit 8:
Corotron 9 Registration roller 10: Group 1 Sensor 11: Transfer corotron 12: Photosensitive drum 1
3: Peeling corotron 14: Fixing device 15: Paper discharge tray 15: RO317: Charger 18: Developing unit 19: Cleaning device 20:
Swinging frame unit 21: Pivot shaft 22: Cam 22a: Long groove 22b one end 23: Cam follower 24: Main frame 25: 11 Frame unit 26: Positioning pin 27: Slide rail 28: Drive motor 29: Motor 30: Cam shaft 3゛1 lever 32: Photoreceptor shaft 33 racking roll 34: Counter balance spring 41: Displacement sensor 42: Δ/D converter 43: Motor controller 44: Motor driver 44: Motor driver 44: Motor driver

Claims (1)

[Scope of Claims] 1. A swinging frame is pivotally mounted to a main frame on which a transfer conveyance drum is pivotally supported, and a sliding frame containing an image forming means including a photosensitive drum is attached to the swinging frame for transferring the image to the swinging frame. A swing support mechanism is provided so as to be removable in the axial direction of the conveyance drum, and further swing the swing frame so that the distance between the transfer conveyance drum and the photosensitive drum is maintained substantially constant. An image output device characterized by: 2. The swing support mechanism includes a cam provided on the main frame side and a cam follower provided on the swing frame side and engaged with the cam. Image output device. 3. The image output device according to claim 1, wherein the swing support mechanism includes a tracking roll that is provided coaxially with the photosensitive drum and presses against the peripheral surface of the transfer conveyance drum.