JPS63267980A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of creases of a material to be transferred by pressing both end parts of the material to be transferred with a pressing means, which is provided before a pair of fixing rolls, to make them lower than a guide means. CONSTITUTION:A form guide 51 is provided in the entrance part of a pair of fixing rolls 21, and pressing members 52 and 52 are provided which depress both end parts of the form guided by the form guide 51 to make them lower than the form guide 51. Both end parts of the form carried on the form guide 51 by pressing members 52 and 52 are pressed to form this form into a shevron shape. Consequently, the form is formed along the inverted crown of a heat roll 21a and is inserted between the pair of fixing rolls 21. Thus, the occurrence of creases of the form is surely prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an image forming apparatus applied to, for example, an electronic one-shot camera.

(Prior Art) As is well known, in an electronic copying machine, a sheet of paper onto which a toner image has been transferred is peeled off from a photoreceptor drum and then conveyed to a pair of fixing rollers, where a fixing operation is performed. Conventionally, when a sheet of paper passes through a pair of fixing rollers, the pair of fixing rollers may cause wrinkles in the paper.

Therefore, Utility Model Publication No. 55-123955, Utility Model Publication No. 60
As shown in Japanese Utility Model Publication No. 9806 and Japanese Utility Model Publication No. 60-14284, the conveyed paper is guided to the inlet of the pair of fixing rollers, and the central part along the longitudinal direction of the pair of fixing rollers is connected to both ends. A method of preventing paper wrinkles by providing a paper guide with a higher mountain shape and supplying the paper transported by the paper guide to a pair of fixing rollers with both ends hanging lower than the center part. is being developed.

However, even with this method, if the leading edge of the paper is curled, it is unlikely that both ends of the paper will hang lower than the center of the paper following the paper guide. In particular, when copying on both sides of a sheet of paper or making multiple copies on the same side, the toner image is once again transferred and fixed onto the sheet of paper that has been developed and fixed, so when it has passed through the pair of fixing rollers during the first copying operation, The leading edge of the paper curls, and during the second copying operation, the paper cannot be reliably fed to the pair of fixing rollers, causing wrinkles or, in the worst case, a jam.

(Problems to be Solved by the Invention) This invention solves the problem of wrinkles occurring in the transferred material that has passed through the pair of fixing rollers. It is an object of the present invention to provide an image forming apparatus that can prevent wrinkles from forming.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes a pair of fixing rollers to which a transfer material onto which a developer image has been transferred is supplied and which fixes the developer image onto the transfer material. In the image forming apparatus, a guide member that guides the transfer material to a pair of fixing rollers, and a guide member provided near both longitudinal ends of the fixing roller pair, and a guide member that guides both ends of the transfer material guided by the guide means from the guide member. It consists of suppression means to lower the

(Function) This invention reliably supplies the transferred material to the fixing roller pair in a chevron shape by pressing both ends of the transferred material and lowering it below the guide means using a suppressing means provided in front of the fixing roller pair. This prevents wrinkles from forming on the transferred material.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 5 and 6 schematically show an image forming apparatus of the present invention, such as a copying machine. A document table (transparent glass) 2 for holding a document is fixed to the top surface of the copying machine main body 1. This document table 2 is provided with a fixed scale 2□ for setting the document 7JQ, and furthermore, a document cover 11 that can be opened and closed is provided near the document table 2. The document placed on the document table 2 is exposed and scanned by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, and 7 reciprocating along the lower surface of the document table 2 in the direction of arrow a. It has become so. In this case, mirror 6.7 moves at half the speed of mirror 5 so as to maintain the optical path length. The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the light irradiation of the exposure lamp 4 is reflected by the mirror 5.
6.7, passes through the variable borrowing lens block 8, is further reflected by mirrors 9□, 92.93, and is guided to the photoreceptor drum 10.
The image is formed on the surface of 0.

The photosensitive drum 10 rotates in the direction indicated by the arrow in the figure, and the surface is first charged by the charging device 11, and then the image is exposed to slit light at the exposure section ph, thereby forming an electrostatic latent image on the surface. be done.

This electrostatic latent image is produced by a developing device 12 that contains, for example, red or black toner, and is selectively operated as required.
1.122, the image is visualized by adhering toner.

The developer 12. ．． 12.2 are detachable from the copying machine main body 1, and the color of the toner contained in these developing units 121 and 122 is determined by, for example, a plurality of connectors (not shown) provided on the copying machine main body. It is set by the connection state of the pin.

On the other hand, sheets of paper (material to be transferred) are taken out one by one from the selected upper paper feed cassette 131 or lower paper feed cassette 132 by the feed rollers 141 and 142 and the pair of rollers 15□ and 152, and are taken out from the paper guide path 16. ．． 162, and is guided to a pair of registration rollers 17, and guided to a transfer section by this pair of registration rollers 17.

Here, the paper feed cassettes 13□ and 132 are removably provided at the lower right end of the main body 1, and one of them can be selected from an operation panel to be described later. Further, the cassette size of each of the paper feed cassettes 131 and 132 is detected by a cassette size detection switch 601 and 602, respectively. The cassette size detection switches 601 and 602 are composed of a plurality of microswitches that are turned on and off according to the insertion of cassettes of different sizes.

Furthermore, a manual feed guide 13a is provided on the upper surface of the paper feed cassette 131.
The paper manually inserted through the feed roller 14a
The sheet is guided to the pair of rollers 151 by the roller pair 151, and is then conveyed in the same manner as sheets fed from the sheet feed cassette 131.

On the other hand, the paper sent to the transfer section comes into close contact with the surface of the photoreceptor drum 10 at the transfer charger 18, so that the toner image on the photoreceptor drum 10 is transferred by the action of the charger 18. Ru. This transferred paper P is transferred to the peeling charger 1
The transferred image is electrostatically peeled off from the photosensitive drum 10 by the action of step 9, is conveyed by the conveyor belt 20, and is sent to the fixing roller 21 as a fixing device provided at the end of the conveyor belt. It will be established. Then, the paper after the ankle is discharged to a tray 25 outside the main body 1 by a pair of delivery rollers 22. Further, after the transfer, the photosensitive drum 10 is returned to its initial state by removing residual toner on the surface by a cleaner 26 and erasing an afterimage by a static elimination lamp 27. In addition, 2
9 is a cooling fan for preventing the temperature inside the main body 1 from rising. Further, the exposure lamp 4 and the mirror 5 are provided in the first carriage 411, and the mirror 6.7 is provided in the second carriage 412.

Further, the first carriage 411 is provided with a spot light source 131 which is movable in a direction orthogonal to the direction of movement of the first carriage 411 and which specifies, for example, an erasing range of the document.

Furthermore, an erasing array 15 in which a plurality of light emitting elements are arranged along the longitudinal direction of the photoreceptor drum 10 is located between the charger 11 for charging the photoreceptor drum 10 and the exposure section ph.
0 is provided, and when performing partial erasure of a document image, the light emitting elements constituting this erasure array are turned on corresponding to the erasure area designated by the spot light source 131, for example, and the light emitting elements of the photoreceptor drum 10 are illuminated. It is designed to remove static electricity. Therefore, an electrostatic latent image is not formed in the portion from which the charge has been removed even if it is subsequently exposed to light at the exposure portion ph, so that the document image is erased.

FIG. 7 shows an operation panel 30 provided on the main body 1 of the copying machine. 30a is a copy key for commanding the start of copying;
30b is a numeric keypad for setting the number of copies, etc.; 30c is a display unit for displaying the operating status of each part, paper jams, etc.;
30d is a density setting section for setting the copy density; 30e is a count command key for displaying the total number of copies and the number of copies for each color; and 30f is operated when another person makes another copy while copying. Interrupt key, 30g is the same size key to set the copy magnification to 100%, 30h is the magnification key operated when setting the copy magnification, 30i is the upper and lower paper feed cassettes 13□, 132. The cassette selection key 30j, which is operated when making a selection, is used to change the color of toner and specify the erase range of the original using the copy light source 131. A mode memory key 301 is operated to read out information such as the erase range stored in the , and an information key 301 is operated to obtain information corresponding to each mode.For example, if a paper jam occurs, this key is pressed. When operated, information for clearing a paper jam is displayed on a display 30o, which will be described later.

30m is a function check key, and by operating this function check key 30m, it is possible to display on the display 30o what kind of function is set. Reference numeral 30n denotes an editing key that is operated when performing partial deletion, multiple copying, double-sided copying, etc. in which a part of the original image is deleted and copied. 30o is a display device made of, for example, a liquid crystal dot matrix panel, and this display device 30
For example, the setting status of the copying machine is displayed in the form of characters at .degree., and when the various cows 30e, 30f, 30g to 30m are operated, the corresponding characters are displayed. Furthermore, if a paper jam occurs during a copying operation, for example, the display 30o displays the location of the paper jam and countermeasures for the jam using text and graphics. Operation keys 30□-304 and 305-308 for selecting various functions displayed on the display 30o are arranged on both sides of the display 30o. Moreover, 30p is the spot light source 13 mentioned above.
This movement key 30p can be tilted in all directions as shown by arrows 30q to 30t, and when these arrows 30Q to 30t are operated, the spot light source 131 moves in the same direction. It is now possible to do so. 30u is a position designation key for inputting the coordinate position indicated by the spot light source 131.

1 and 2 show the pair of fixing rollers 21. FIG. The fixing roller pair 21 includes a heat roller 21a1 and a pressure roller 21 that is in pressure contact with the heat roller 21a.
It is composed of b.

The heat roller 21a is provided with an inverted crown or a taper of about 80 to 200 μm, and the diameter is larger at both ends than at the center, so that the paper conveyance speed is faster. A paper guide 51 is provided at the entrance of the pair of fixing rollers 21 . This paper kite 5
1 is a flat plate, for example, and is slightly shorter than the pair of fixing rollers 21 and is disposed corresponding to the center of the pair of fixing rollers 21 .

A pressing member 52 is provided near both ends of the paper guide 51.
Pulleys 53.53 forming part 52 are provided. These pulleys 53.53 are rotatably provided at the tips of supports 54.54, respectively.
The intermediate portions of the two are rotatably held, and are rotatable in the direction of the arrow shown in FIG. The pulley 53.5
3 is positioned below the surface of the paper guide 51 as shown in FIG. 2 when the supports 54 and 54 are rotated as shown.

FIG. 3 shows a driving device for the support body 54. As shown in FIG. That is, a spring 55 is provided at the proximal end of the support 54, and the spring 55 causes the distal end of the support 54 to
It is always urged in a direction away from the paper guide 51. Further, a solenoid 5 is provided at the base end of the support 54.
6 is provided, and when this solenoid 56 is energized, the support body 54 is rotated as shown by the solid line in the figure, against the energizing force of the spring 55.

FIG. 4 shows the main parts of the control system. The control section 61 controls the operation of the entire copying machine, and includes the aforementioned operation panel 30 and the switch 60.
．． ．． 602 etc., a solenoid drive unit 63 that drives the solenoid 56 etc., the first
Carriage 411, second carriage 412, motor drive unit 64 that drives and controls motors that drive photosensitive drum 10, fixing roller pair 21, etc., lamp regulator 65 that controls lighting of exposure lamp 4, and charger 11 for charging.
etc. are connected.

In the above configuration, the operation will be explained.

The control section 61 controls the motor control section 64, lamp regulator 65, charging device 11, etc. according to the mode set on the operation panel 30 to execute the above-described copying operation. Then, the required copying operation is performed, and the paper onto which the toner image has been transferred from the photoreceptor drum 10 is
After being peeled off from the photoreceptor drum 10 by the peeling charger 19, it is conveyed to the fixing roller pair 21 by the conveyor belt 20. At this time, the control section 61, the solenoid drive section 6
3, the solenoid 56 is energized and the pulley 53.53
is moved to the position shown in FIGS. 1 and 2. In this state, when the paper is guided on the paper guide 51, both ends of the paper along the qualitative roller pair 21 are pressed downward from the paper guide 51 by the pulley 53, so that the paper is shown as a dotted line in FIG. As shown, the fixing roller pair 21 is shaped like a mountain so that the part corresponding to the center of the fixing roller pair 21 is higher.
inserted into. Therefore, the sheet inserted into the pair of fixing rollers 21 moves faster at the center than at both ends.
Because both ends are in contact with the fixing roller pair 2,
1, and the wrinkles in the paper are further smoothed out by the inverted crown of the heat roller 21H.

When the leading edge of the paper is inserted into the fixing roller pair 21, the control unit 61 and the solenoid drive unit 63 activate the solenoid 56.
is deenergized, and the pulleys 53, 53 are rotated as shown by dotted lines in FIG. 3 and separated from the sheet. Therefore, from now on, the paper is guided by the paper guide 51 and fixed by the pair of fixing rollers 21.
will be passed through.

According to the above embodiment, the paper guide 51 is provided at the entrance of the pair of fixing rollers 21, and the pressing members 52 and 52 for pressing both ends of the paper guided by the paper guide 51 downward from the paper guide 51 are provided. , this pressing member 52.
52 presses both ends of the paper conveyed on the paper guide 51, thereby shaping the paper into a chevron shape. Therefore, since the paper can be inserted into the fixing roller pair 21 in a shape that follows the inverted crown of the heat roller 21, wrinkles in the paper can be more reliably prevented than in the past.

Further, the pressing members 52, 52 press only the leading edge of the paper, and are separated from the paper when the leading edge is inserted into the pair of fixing rollers 21. Therefore, the pulleys 53 of the pressing members 52 and 52 are applied to the unfixed toner image.
．． 53 does not come into contact with each other, it is possible to prevent deterioration of image quality.

Although the above embodiments have been described using an ordinary electronic copying machine, it goes without saying that the present invention can be applied to electronic copying machines capable of performing duplex or multiple copying operations, for example.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As described in detail above, according to the present invention, by pressing both ends of the transfer material by the suppressing means provided in front of the pair of fixing rollers and lowering the transfer material from the guide means, the transfer material is By reliably feeding the fixing roller pair in the form of a chevron,
An image forming apparatus that can prevent wrinkles from forming on a transfer material can be provided.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention; FIG. 2 is a side view of FIG. 1; FIG. 3 is a configuration diagram showing only the suppressing member; FIG. 4 is a block diagram showing a control system, and FIGS. 5 and 6 each show an image forming apparatus to which the present invention is applied. FIG. 5 is an external perspective view, and FIG. 6 is a side sectional view. , FIG. 7 is a plan view showing the configuration of the operation panel. DESCRIPTION OF SYMBOLS 1... Copying machine main body, 21... Fixing roller pair, 21a
...Heat roller, 21b...Pressure roller, 30.
...Operation panel, 51... Paper guide, 52... Pressing member, 53... Pulley, 54... Support body, 56...
・Solenoid, 61...control unit. Figure 1 Figure 12 Figure 4

Claims (3)

[Claims] (1) In an image forming apparatus having a pair of fixing rollers to which a transfer material to which a developer image has been transferred is supplied and which fixes the developer image to the transfer material, the transfer material is guided to the fixing roller pair. An image forming apparatus comprising: a guide member; and a pressing means provided near both ends of the pair of fixing rollers in the longitudinal direction and lowering both ends of the transfer material guided by the guide means below the guide means. (2) The pressing means includes a support whose base end is rotatably held near the pair of fixing rollers, and a rotatable pulley provided at the tip of the support for pressing the transfer material. 2. The image forming apparatus according to claim 1, wherein the pulley is moved near the guide means in accordance with the timing of supply of the transfer material to the pair of fixing rollers. (3) The image forming apparatus according to claim 1, wherein the fixing roller pair includes a heat roller provided with an inverted crown and a pressure roller that is pressed against the heat roller. .