JP3219791B2 - Electrophotographic copier with improved fuser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to electrophotographic copiers such as printers and copiers that use pressure to fuse toned or toner images. In particular, the present invention provides a method for multiplexing various images in an envelope or the like in at least a short time.
Or a fusing device that can be fused to a multilayer transfer medium
Or fuser .

[0002]

2. Description of the Related Art In the case of an electrophotographic printer, for example, an envelope as well as a cut sheet of paper is a transfer medium on which information is printed. Generally, such printers use a fuser or fusing device for fusing a toner image of information to be printed on paper or an envelope. Such a fuser is usually constituted by a fusing roller which is urged against a backup roller, and forms a pressure holding portion through which the transfer medium passes. In one form of such a fuser, the fuser roller has a heated and relatively hard outer surface, while the backup roller is softer and can be somewhat deformed to form the pressure nip.

[0003]

Normally, paper passes through this type of fuser without difficulty, but in the case of envelopes it is creased, folded or dendritic (known as "Treeing"). Or, a fold may be formed. The cause of such a problem may be due to non-uniform supply or non-uniform delivery along the envelope surface due to multiple overlapping in the envelope or the like. To correct such problems, segmented or segmented pressure rollers are used, or rollers of various shapes are used. Another solution to the problem is to utilize the provision of a non-printing area at the leading edge or leading edge and the trailing edge or trailing edge of a single envelope.
In this method, a small amount of pressure is applied to the leading end and the trailing end at the holding portion of the fuser, and the large force required at the holding portion for fusion is applied only to the place where the toner image is placed on the envelope. I am trying to be. This can improve the situation somewhat, but will still cause folds and wrinkles along the printable area of the envelope.

It is a general object of the present invention to provide an electrophotographic copying machine of the above type that can substantially eliminate the formation of folds, folds, and dendritic wrinkles from various envelopes and the like.

[0005]

SUMMARY OF THE INVENTION In order to implement the present invention, there is provided an electrophotographic copying machine, wherein the transfer medium is advanced by passing the transfer medium through a pressure zone. A fuser for fusing the color image to the transfer medium, the pressure on the transfer medium in the pressure area is once or more at short intervals during the fusing step,
It has been substantially reduced. An advantage according to the present invention is that virtually all wrinkles and dendritic folds are eliminated from the envelope fused by the apparatus, and a suitable fused state of the image is obtained. In one embodiment of the present invention, the fuser has a configuration in which a heat fusing roll and a backup roll are mutually biased by a spring force to form a pressure holding portion, and this spring force is applied during the fusing. At least once at short time intervals. Further objects and advantages of the present invention and methods of practicing the same will become apparent from the following description with reference to the drawings.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS While the present invention is susceptible to various modifications and alternative forms, specific embodiments thereof will now be described by way of example only with reference to the drawings. It is apparent that the present invention is not limited to the particular forms disclosed herein, but encompasses all modifications and alternatives within the spirit and scope of the invention.

In FIG. 1, an electrophotographic printer 11
A conventional imaging station, development or image development station, collectively designated by the numeral 12, to form a toner image or toned image on a transfer medium such as an envelope 13;
And a transfer station. The toner image on the envelope 13 is held between a fusing roll 16 and a backup roll 17 which are mutually biased by a spring 18.
After passing through 4, it is fused to the envelope by heat and pressure.

In the illustrated printer, the fuser roll 16 is heated by an internal heating lamp (not shown) or the like, so that the fusion of the toner image onto the envelope 13 passes through the holding portion 14 and the heat and pressure are reduced. It is performed in union. Thus, the envelope 13 is discharged from the printer 11 along the passage 19 after passing through the holding portion 14. According to the present invention, when the envelope 13 is moved through the
The force of the spring 18 that biases the springs 17 and 17 is eliminated several or more times during the fusing process, either instantaneously or at short intervals. This allows the layers that make up the envelope itself to move with respect to each other, substantially eliminating wrinkling and fold formation during fusing of the envelope.

In order to release the spring force, the solenoid 2 which operates to reduce the force of the spring 18 is used.
1 while the envelope 13 is passing through the holding portion 14,
Start up momentarily. To do this, the envelope 13
Starts passing through the holding portion 14, and the sensor 22 senses or detects the leading end or leading edge of the envelope 13. In response to sensing or detecting the leading end of the envelope 13, the function generator 23 momentarily supplies a drive signal to the solenoid driver 24 to drive the solenoid 21. The supply of the drive signal is repeated several times while the envelope 13 passes through the fusion holding section 14.

Referring to FIGS. 2 and 3, a fusing roll 16 is used.
And 17, the spring 18, and the solenoid 21, the fusing rolls 16 and 17 are attached to the frame 31 at each end thereof. The fuser roll 16 is a heated roll (heated by an internal incandescent lamp not shown) and has a hard outer surface coated with Teflon or equivalent. The backup roll 17 has a yieldable surface on which a layer of a material such as silicone rubber is formed. The fusing roll 16 is rotated by inserting the end of the fusing roll into bearings 32 (partially broken in FIG. 2) and 33. The backup roll 17 includes a spindle 34 rotatably supported in a ball bearing 36 at one end of the backup roll, and an equivalent spindle 37 rotatably supported in a ball bearing 38 at the opposite end. Have. The spindles 34 and 37 extend from a metal core (not shown) of the backup roll 17, and the metal core of the backup roll 17 is covered by silicone rubber in contact with the fusion roll at the fusion nip. ing.

The fusing roll 16 is driven by a drive mechanism (not shown) of the printer via a gear 42 fixed to one end of the roll 16. Backup roll 1
7 is loaded against the high-temperature fusing roll 16 by the spring 18 and the spring 43 at the opposite end of the roll, and is driven by friction with the high-temperature roll 16. This flexible backup roll 17
Causes the backup roll 17 to have a slight flattening along its longitudinal direction,
This deformation will define the clamping or contacting portion of the fuser roll.

The spring 18 is connected to the portion 4 of the frame 31.
The lower end is supported by a plastic spring holder 44 (not shown in FIG. 2) fixed on the lower end 6. The upper portion of the spring 18 is housed in a portion 47 of a plastic backup roll support housing 48 that carries a backup roll bearing 36.

At the opposite end of the rolls 16, 17, a spring 43 is supported at its lower end by a spring holder 49, which is further supported by a portion 51 of the frame 31. Support housing 48
The support housing 52 corresponding to the above-mentioned structure accommodates the upper end of the spring 43 and holds the backup roll bearing 38. The spring 43 urges the support housing 52 and the bearing 38 upward, and the spring 18 engages the support housing 48 and the bearing 3.
6 is urged upward, so that the pressure between the fusion roll 16 and the backup roll 17 at the fusion holding portion is maintained.

In the illustrated printer, the envelope is fed near the end of the nip of the fuser roll adjacent to spring 18 and bearing 36. The pressure at the nip at this end of the fuser roll is momentarily released several times during the fusing process on the envelope by exerting a force that overwhelms the spring 18.

This force overcoming the load on spring 18 is provided by solenoid 21. Solenoid 21
Is fixed to a bracket 53 attached to the frame 31. A pin 57 is attached to the core 54 of the solenoid 21. The pin 57 has an expanded cylindrical head 58 which is housed in a spring clip 59 mounted in the support housing 48. The pin 57 then extends through an opening in the bottom 61 of the spring clip 59 and can tilt and move slightly in any direction to adjust for misalignment between the solenoid 21 and the support housing 48.

When the solenoid 21 receives the drive current, the pin 57 and the supporting housing 48 are pulled down against the force of the spring 18, and the end of the fusing roller through which the envelope passes and the solenoid 21 is disposed. The pressure of the fusion clamping portion at the portion is released.

The envelope 13 is driven into the fusion holding section by a paper feed mechanism (not shown) of the printer. While the envelope 13 is passing through the holding portion, stress is generated on the paper overlapping surface of the envelope. Such stresses generally cause corrugations or bubbles formed between the two layers of the envelope 13.

In the printer according to the present invention, when the leading end of the envelope 13 moves out of the holding portion and continues to the paper path 19, the envelope engages with the exit flag 62 and the photo sensor 63
Will be started. The exit flag 62 and the photo sensor 63 include the sensor 22 shown in FIG. The pulse due to the activation of the photo sensor 63 starts the operation of the electric driver circuit 24 for driving the solenoid 21 and the function generator 23.

By activating the solenoid, the stress on the envelope 13 is alleviated, and the air bubbles disappear. As the envelope 13 continues to move past the clamp, additional stress is generated and additional air bubbles are formed. Therefore,
After a selective time interval from the first activation as described above, the solenoid 21 is activated again to release the pressure between the fusing roll and the backup roll at the solenoid-arranged ends of the rolls.

In the present embodiment, the interval between pulses to the solenoid is selected depending on various parameters. The above stresses accumulate at a rate that depends on the weight of the paper used to form the envelope (eg, 16 to 24 pounds), humidity conditions, and the like. In the illustrated fuser mechanism, the activation interval of the solenoid is set to approximately 3.81 cm (1.5
It has been found that a spacing of 5.0 inches (2 inches) to 5.08 cm (2 inches) provides satisfactory operation for various papers and normally established humidity.

After fusing, the upper re-drive roll 64 and the lower re-drive roll 66 in the printer pull the envelope 13 along the passage 19 as the envelope 13 is ejected through the fuser roll clamp. The function generator 23 and driver 24 continue to pulse the solenoid until the envelope 13 is pulled along the paper path 19 and its trailing edge or trailing edge exits the fuser clamp.

When the solenoid pulsates, the current from the solenoid driver to the solenoid is controlled so as to rise or fall at its contour as described below. This current waveform minimizes the operation of the backup roll and solenoid mechanisms and keeps the mechanisms silent. The duration of the solenoid pulse is such that the separation between the fuser roll 16 and the backup roll 17 occurs for about 20 milliseconds. This provides time to relieve the stress accumulated in the envelope 13 and to fuse all parts of the envelope for a sufficient time to fuse the toner image onto the envelope with adequate quality. It is maintained under the pressure of the holding portion.

As one form of the fuser, the envelope 13 has
It enters the fuser clamp at a speed of 5.08 cm (2 inches) per second. Approximately 6803.85 grams (15 grams) between the silicone rubber backup roll and the rigid hot roll
A pressure load of about 1 lb. causes the backup roll to deform by about 0.100 inches. Thus, a given section of the envelope will be in the fuser nip for about 50 milliseconds. The set temperature for the fuser roll clamp is about 180 ° C. Such pressure,
Heat and time are sufficient to achieve good fusion quality over a wide range of operating conditions.

As described above with reference to FIG. 1, once the leading end of the envelope 13 reaches the paper discharge sensor 22, a signal is sent to a function generator 23 which triggers a voltage pulse. This voltage pulse is applied to the current driver 24
The current driver converts this into a current used to drive a linear push-pull solenoid 21.

As shown in FIG. 4, after receiving the trigger signal, the leading end of the envelope is re-rolled (64, FIG. 2).
A time interval sufficient to reach 66) elapses before the first solenoid pulse is started. At this delay time interval, about 3.81 cm (1.5 inches) from the leading edge of the envelope
At this point, the first pulse is generated. This distance is indicated by the symbol X ₀ in FIG. In this illustrative example of the invention, a number of pulses and their intervals are controlled by a function generator 23. For this purpose, as one mode of the present invention, Wavetech 175 (Wave)
Arbitrary waveform generators such as tek175) have been used. Advantageously, the function generator signals can be produced by control software for the printer as part of a general printer control function.

In this embodiment, such pulses occur at about one second intervals or at 5.08 cm (2 inch) intervals along the envelope. As a result, No. 10 (9.5
Inch / approximately 24.13cm) Envelope has 4 pulses, 73/4 (7.5in / approximately 19.05cm)
The envelope has three pulses. The length of the envelope can be automatically determined by measuring the switching time difference of the paper sensor switch in the pre-fuser stage section 12 of the printer 11. This information is used by the function generator 23 to determine the required number of solenoid pulses.

The current pulse generated by driver 24 tracks the voltage generated by function generator 23 and takes the shape shown in FIGS. Solenoid 21
The current pulse to move the backup roll as shown in FIG. The movement required to separate the rolls is about 0.0762 c in this embodiment of the invention.
m (0.030 inch). The separation time for proper functioning can be as short as 5 ms and as long as 20 ms. Under these constraints, the envelope has enough time to relax and has no significant effect on fusing quality. In this fuser configuration, the heating roll is a 1 mm thick aluminum tube, 0.00254 cm
(0.001 inch) thick Teflon
n), with a coating of Silverstone or equivalent. The backup roll consists of a 10 mm diameter inner steel rod and a 6 mm thick 25 durometer silicone rubber roll with Shore hardness.

[0028]

As described above, the electrophotographic copying machine according to the present invention is provided with a fuser having a fusing / holding portion through which the transfer medium passes and advances in order to fuse the color tone image onto the transfer medium. The pressure on the transfer medium with the fuser is increased at least once at short intervals during the fusing step;
Since the color tone image is substantially reduced, various wrinkles, dendritic folds, and the like are not formed on the envelope to which the color tone image is fused, and a proper fusion state of the color tone image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of an electrophotographic copying machine or printer according to the present invention.

FIG. 2 is a schematic side view of a main part of a fuser mechanism according to the present invention.

FIG. 3 is an external view including a partial cross section of the fuser shown in FIG. 2;

FIG. 4 is a schematic diagram showing a position on an envelope to be processed at a reduced clamping pressure during a fusing step in the electrophotographic copying machine according to the present invention.

FIG. 5 is a schematic diagram showing a reference voltage waveform output from a function generator or a solenoid current waveform output from a driver at each of the holding portion pressure decreasing positions.

FIG. 6 is a schematic view showing a state of movement of a fusing backup roll with respect to a solenoid current at each of the holding portion pressure decreasing positions.

FIG. 7 is a schematic diagram showing a solenoid current waveform at each of the holding portion pressure decreasing positions.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Electrophotographic copying machine 12 Developing and transferring means 13 Envelope 14 Fusion holding part 16 Fusion roll 17 Backup roll 18 Spring 19 Paper passage 21 Solenoid 22 Sensor 23 Function generator 24 Driver

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Larry Joe Rice United States 40356 Kentucky, Nicholasville, Lantern Way 90 (72) Inventor John O'Neill Shafer United States 40511 Kentucky, Lexington, Salisbury Drive 3760 (56 References JP-A-3-197989 (JP, A) JP-A-60-195574 (JP, A) JP-A-61-294477 (JP, A) JP-A-63-43165 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (15)

(57) [Claims] 1. An electrophotographic copying machine, comprising: means for developing an image having a color tone and transferring the color tone image to each transfer medium which is sequentially sent; and welding means for welding the said color tone images in respective transfer medium by advancing passes through the transfer medium to the pressure clamping portion, the on each transfer medium being fed the step-by-step
While the color image is being advanced to the pressure holding portion, the color image
An electrophotographic copying machine comprising: means for substantially reducing the pressure in the pressure holding portion at least once at short intervals regardless of the presence or absence of the region . Wherein said fusing means comprises a pair of fusing rolls biased to one another, the transfer medium is a pressure clamping portion passing, electrophotographic of claim 1 Copy machine. 3. At least one of the fusing rolls is heated.
The electrophotographic copier of claim 2 , wherein the copier is heated . Wherein both of said fusing roll, electrophotographic copying machine, wherein a biased one another, to claim 2 by concatenated spring on one of the rolls. 5. The spring is connected at one end to one of the rolls and at the other end to a solenoid mounted on a copying machine to substantially reduce pressure in the pressure clamp. reduction means, start the solenoid comprises means for removing the spring force from one of said rolls, electrophotographic copying machine according to claim 4. 6. An electrophotographic copying machine, comprising: means for developing a toned image and transferring the toned image to a transfer medium; and advancing the transfer medium with the toned image to a pressure holding portion. Means for fusing the color image to the transfer medium by passing the image to the pressure holding portion of the color image on the transfer medium.
Means for substantially reducing the pressure of the pressure holding portion at least once at short time intervals, regardless of the presence or absence of the toned image area during the passage of the transfer medium, and the transfer medium passing through the pressure holding portion. Means for detecting the position of the transfer medium during the transfer, and providing a position signal in response to such detection of the transfer medium, wherein the means for substantially reducing the pressure of the pressure holding portion is provided. An electrophotographic copier comprising responding to a position signal. 7. The printer according to claim 1, wherein said electrophotographic copying machine is a printer.
The electrophotographic copying machine according to claim 6 . 8. A printer, to express an image tinged color, and means for transferring the said color tone images in multiple layers transfer medium, be advanced through said transfer medium carrying said color image to a pressure clamping portion Fusing means for fusing the color tone image to the transfer medium by means of: advancing the transfer medium and the color tone image to the pressure holding portion
During fusing, regardless of the presence or absence of the toned image area
And moving the multiple layers of the transfer medium relative to each other.
A printer for reducing the pressure at the pressure holding portion to a sufficient extent at least once at short time intervals. 9. The multi-layered transfer medium has two layers,
A multi-layered transfer medium having at least one edge
9. The method of claim 8, wherein the two layers are connected along an edge.
The printer as described . 10. The transfer medium according to claim 9, wherein said transfer medium is an envelope.
The printer according to . 11. An electrophotographic copying machine, comprising: means for developing a color-tone image and transferring the color-tone image to a transfer medium; Means for fusing the toned image to the transfer medium by advancing it past a pressure nip defined by a pair of biased fusing rollers; and means for fusing the toned image on the transfer medium. To pressure holding part
During the forward pass of the
The fusing roller is separated at least once at short intervals.
It allows electrophotographic copying machine and means for substantially reducing the pressure in said pressure clamping unit. 12. An electrophotographic copying machine, comprising: means for developing a toned image and transferring the toned image to a transfer medium; and means for forming a pressure holding portion wider than the transfer medium. A pair of fusing rollers biased against the transfer medium, the pair of fusing rollers comprising the transfer medium being advanced through the end of the pressure holding portion with the color image thereon. To the pressure holding portion of the color image on the transfer medium
During the forward pass of the
Not more than once in a short time interval, xerographic copiers and means for substantially reducing the pressure at said end of said pressure clamping unit. 13. An electrophotographic copying machine, comprising: means for developing a toned image and transferring the toned image to a transfer medium; and pressure-pressing the transfer medium having the toned image thereon. Means for fusing the toned image to the transfer medium by advancing through the portion, and to the pressure holding portion of the toned image on the transfer medium.
Irrespective of the presence or absence of the toned image area during the passage of
Not, electrophotographic copying machine comprising means for substantially reducing the pressure in said pressure clamping unit in timed period. 14. An electrophotographic copying machine, comprising: means for developing a toned image and transferring the toned image to a transfer medium; and pressure-holding the transfer medium having the toned image thereon. Means for fusing the toned image to the transfer medium by advancing through the portion, and to the pressure holding portion of the toned image on the transfer medium.
During the forward pass of the
Not, electrophotographic copying machine comprising means for substantially reducing the pressure in a fixed period in the movement distance of the transfer medium. 15. An electrophotographic copying machine, comprising: means for developing a toned image and transferring the toned image to a transfer medium; and pressure-holding the transfer medium having the toned image thereon. Means for fusing the toned image to the transfer medium by advancing so as to pass through the transfer medium, and to the pressure holding portion of the toned image on the transfer medium.
During the forward pass of the
At least once in a short time interval and the length of the transfer medium
Means for substantially reducing the pressure at the pressure clamping portion by a number of times set by the electrophotographic copying machine.