JPS61138977A - Fixing device - Google Patents

Abstract

PURPOSE:To obtain fixation conditions suitable to respective modes such as a variable power copy mode, a color copy mode, and a halftone reproduction mode by varying a pressure load between a heat roller and a pressure roller according to process speeds suitable for the respective modes. CONSTITUTION:The pressure roller 341 of a fixing device 25 which heats and fixes a developer on a form after transfer image formation on a photosensitive body by the heat roller 338 and pressure roller 341 is pressed with the energizing force of an energizing member, e.g. compression spring 342, and the 1st female screw 347 is moved up and down by the rotation of a stepping motor 349 through screw members, e.g. the 1st female screw 347 and the 2nd female screw to vary the in-use length l of the compression spring 342, thereby setting the load between the heat roller 338 and pressure roller 341 according to process speeds of respective modes. Consequently, the fixation conditions suitable for the variable power copy mode, color copy mode, and halftone reproduction mode are obtained to prevent the wrinkling and curling of the form, and a defect in fixation and an offset securely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fixing device applied to an image recording apparatus to which an electrophotographic method is applied, such as a copying machine.

[Technical background of the invention and its problems]

In recent years, image recording devices that apply electrophotographic technology, such as electronic copying machines and radar printers, have become increasingly multi-functional and complex as systems.

゛ This trend is caused by many factors, such as faster image formation, the recording of color images as well as black and white images, and the diversification of image sizes due to the introduction of enlargement/reduction mechanisms. There is a strong demand for making the entire device more compact and lowering the price, which has resulted in many restrictions on the space and drive devices for each device assembled and housed within the main body.

Therefore, in order to meet the above requirements with one device,
It is most practical to change the process speed of image formation for each mode, but in particular, it is possible to change the process speed of image formation for each mode. If the fixing device has multiple modes with different process speeds, it is configured to match the highest speed conditions, so it can be used in variable ratio copying, color copying, halftone reproduction mode, etc. under the same conditions. If paper is used for
A possible solution to this problem is to change the fusing temperature for each mode, but while this does not require any special equipment, it takes too much time to dissipate and accumulate heat from the heat roller, making it difficult to switch modes quickly. There is a problem that seems impossible.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a reliable fixing device with a speed of 5 Kt, which can easily and quickly switch between modes.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides a fixing device that heats and fixes a developer image transferred and formed on a support by an image carrier using a heat roller and a pressure roller, A pressing force is applied to the roller by the urging force of an urging member, and the working length of this urging member is varied via a cam mechanism to adjust the pressing force of the pressure roller to the image forming speed. This feature is characterized in that it can be adjusted according to the pressure, thereby minimizing variations in pressure and almost eliminating the time spent switching modes.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the external appearance of an image forming unit device employing the fixing device of the present invention, and FIG. 2 is a schematic longitudinal sectional front view thereof.

In the figure, 1 is a copying device as an image forming speed, and 2 is a paper P which also serves as a mounting table on which the copying device 1 is placed and serves as an image support (image recording material) discharged from the discharge section of the copying device 1.
This is a direction changing/conveying device that receives the paper PIC as needed and guides it to the copying apparatus 1 again in the same state or with the front and back reversed in order to form multiple or double-sided images on the paper PIC. Reference numeral 3 denotes an automatic feeder which is mounted on the top surface of the copying apparatus I and automatically feeds the original A.

The copying apparatus I is constructed as shown in FIG.

That is, numeral 4 in the figure is a main body of the copying apparatus, and on the upper surface of the main body 4 of the copying apparatus, a document A to be fed by the automatic document feeder 3 is placed. A document placement glass 5 serving as a document placement section is provided, and an operation panel 6, which will be described later in FIG. 4, is provided at the front edge of the top surface.

Further, a paper feed cassette 7.
8.9 is installed. Further, the upper paper feed cassette and the cassette cover 10 on the door serve as a manual paper feed tray 1 for manually feeding paper P as appropriate.

An image carrier, that is, a drum-shaped photoreceptor 12 is arranged approximately at the center of the main body 4 of the copying apparatus.

Around this photoreceptor 12, there is a charging device 13, an exposure optical material 14, a two-color developing device 15, which will be described later, and a transfer device 16.
, peeling device 17, cleaning device I8, and afterimage erasing device 1
9 are arranged in sequence.

In addition, paper feed cassettes 7, 8, .
Paper 2 supplied from the automatic paper feeder 20 to which 9 is attached
1 Manually fed from the manual feed tray 1, the required paper P1 and the paper P guided from the direction conversion conveyance device 2 are transferred to the copying apparatus main body 4 through the image transfer section 21 between the photoreceptor 12 and the transfer device 16. A paper conveyance path 23 leading to the discharge section 22 provided on the left side of the paper is formed.

Further, a pair of aligner rollers 24 is arranged on the upstream side of the image transfer section 21 of the paper conveyance path 23, and a fixing device 25 and a pair of paper discharge rollers 26 are arranged on the downstream side.

Further, the operation panel 6 is as shown in FIG. 4.

That is, on the right end side of the operation panel 6 there is a start button /30,
Three numeric keys and a total counter 32 are arranged, and on the left end side there is a mode switch getan 33 and a one-sided copy mode display L.
ED 34, double-sided copy mode display LED 35, double copy mode display LED 36, density adjustment button 37
, an automatic exposure button/38, and a first display section 39 are arranged. Further, in the center part, a reduced display section 40, a same-size display section 41, an enlarged display section 42, a variable magnification button 43, a zoom button 44, a color selection g button 45, and a second display section 46 for displaying the status are arranged. The situation is as follows.

Further, as shown in FIGS. 5 and 6, the exposure optical device 14 includes an exposure lamp 51 as an exposure light source that is surrounded by a rear portion 7 and a reflector 50 and irradiates light onto the document placement surface 5; a first optical unit 53 that has a first mirror 52 as a reflecting member that reflects light reflected from the document placement surface 5a in a predetermined direction and is movable along the document placement surface 5a;
It moves in the same direction in synchronization with this first optical unit 53 at a speed that is half the speed of the first optical unit 53, and transfers the optical image reflected by the first optical unit 53 to the lens unit 54. The second mirror 55 and the third mirror 5 reflect
A second optical unit 57 with 6 is provided.

Furthermore, a third optical unit 60 having a fourth mirror 58 and a fifth mirror 59 as reflecting members is provided downstream of the lens unit 54, and the optical image reflected by this third optical unit 60 is transferred to the photoreceptor 12 side. The configuration includes a sixth mirror 61 as a fixed reflecting member that reflects light.

Note that 62 is a dustproof glass provided between the sixth mirror 61 and the photoreceptor 12, and 63 is an exposure glass 5.
This is a heat-absorbing glass installed on the front of the screen.

Thus, with the exposure lamp 51 turned on, the first optical unit 53 moves at a speed V along the document placement surface 5a, and in synchronization with this movement, the second optical unit 57 moves.
moves in the same direction at a speed that is half the speed V, thereby scanning the original A placed on the original placing surface 5a, on the photoreceptor 12 as the exposed part which has been rotated in advance. It is designed to form an image.

Then, the photoreceptor I is charged by the charging device 13.
An electrostatic latent image corresponding to the document A is formed on the document A.

The electrostatic latent image thus formed is developed by facing the developing device 15, and then sent to the image transfer section 21 facing the transfer device (i!16), and the developer image is transferred to the aligning roller. 24, the paper P&C is transferred. Next, the paper P on which the image has been transferred is separated from the photoreceptor 12 by a peeling device 17, and then transferred to the conveyance path 23.
The sheet is guided to a fixing device 25 through which the image is fixed, and is discharged to a discharge section via a pair of discharge rollers 26.

On the other hand, the surface of the photoconductor 120 after the paper PK developer image has been transferred is opposed to a cleaning device 18 to clean residual developer (toner) remaining on the photoconductor 12, and then an afterimage erasing device 19, the potential on the photoreceptor 12 is lowered below a partial level to enable the next copying operation.

Further, as described later, the lens unit 54 and two mirrors 51J arranged at an angle of 90 degrees,
A third optical unit 60 having a lens 59 can be moved as shown by arrows A and B in FIG. The structure is as follows.

Further, as shown in FIGS. 3 and 6, a first shielding member 65 which also serves as a lens cover is provided to cover the upper surfaces of the lens unit 54 and the third optical unit 60, and a second shielding member 65 is provided which also serves as a lens cover. The optical unit 57 includes a first shielding member 6
A second shielding member 66 is provided to partially overlap the upper surface of the shielding member 65, and a partitioning means is provided on the upper surface side of the shielding members 65 and 66 to form a cooling air passage 67 along the document placement surface 5a. It makes up 6g. Said second shielding member 6
6 is not attached, the end side is guided over the first shielding member 65 via a support means 69 consisting of a roller or a sliding member, so that no special guide means is required. .

9. The first optical unit 57, the lens unit 5
4 and the lower surface side of the third optical unit 6° are covered with a partition plate 70 that partially holds the dustproof glass 62, and one end of this partition plate 70 is connected to a fan of an exhaust fan 71. It is connected to the casing 72 and substantially partitions the copying apparatus main body 4 into upper and lower sections.

As shown by the arrow in FIG. The image stand glass 5 is protected by the second shielding member 66.
After being guided to ensure that it passes along the lower surface side to the left side surface, it is released to the outside. For this reason,
The exposure lamp 51 can be sufficiently cooled, preventing overheating of the exposure lamp 51 and extending its life, and also preventing adverse effects of heat on other parts as much as possible. Further, heating is prevented over the entire area of the document table 5, so that the operator does not feel uneasy. Also, the second shielding member 6
6 blocks stray light as shown by arrow E, and image defects caused by stray light entering the lens unit 54 can be reliably prevented.

The first optical unit 53 and the second optical unit 57 are mounted and supported as shown in FIG. 57 is configured to be able to move at half the speed V.

That is, the upper horizontal piece 7 is provided on the mutually opposing surfaces of the rear frame 75 and the front frame 76 which are arranged in parallel at a distance.
5m, 76m and parallel guide frame 77.77
are installed and these guide frames 77.77
The first optical unit 53 and the second optical unit 57 are installed in such a state that they are in sliding contact with sliders 78 attached to the lower surfaces of both ends thereof. In this way, the first optical unit 53 and the second optical unit 57, which are provided movably on the f-id frame 77, 77, are moved in a predetermined direction at a predetermined speed by the optical unit actuating means 79. It looks like this.

The optical unit operating means 79 has the following configuration. That is, a drive shaft 80 is horizontally mounted corresponding to one end of the optical unit 53.57 in the moving direction, and drive pulleys 81 and III are attached to both ends of the drive shaft 80, that is, to the outside of both frames 75.76. . A driven pulley 82 is rotatably provided on the outside of the frame 75.76 via a support shaft 83 corresponding to the other end of the optical unit 53.57 in the moving direction.

On the other hand, both ends of the carriage 840 of the first optical unit 53 protrude outside the frame 75, 76, and
Both ends of the carriage 85 of the second optical unit 57 have pulley attachment parts j35m and 85b folded vertically along the outer surfaces of the frames 75 and 76, and a pair of pulley attachment parts j35m and 85b that function as movable pulleys. are each installed.

Furthermore, each pulley 81. A midway portion of the wire 88 is wrapped around lI2.86, 137 in a predetermined state. That is, the wire 88, whose one end is fixed to the fixture 90 via the spring 89, is pulled out to the driven pulley 82 side, wrapped around the first googly 86 of the second optical unit 57, folded back, and then wrapped around the drive pulley 8Z multiple times. Wrap it around the driven pulley 8.
Fold back to the 2nd side. Then connect the wire 8 to the driven pulley 82.
8 to the second pulley 87 of the second optical unit 57.
After being wrapped around and folded back, the other end is fixed to a fixture 92 via a guide 91.

Further, the carriage 84 of the first optical unit 53
Both ends of the wire 88 are directly fixed to the wire 88.

On the other hand, the drive shaft 80 is interlocked with a wrist motor 93 and a timing belt 94, and a wire 88 is wound around the drive shaft 81. Ill is driven in the forward direction or in the reverse direction. Then, the first optical unit 5 is directly fixed to the wire 88.
3 is the speed V, and the second optical unit 57 to which the wire IJ 86 and 87, which acts as a movable pulley and is connected to the wire 88, is attached moves at a speed that is half of the speed V. It is configured to do this.

Further, as shown in FIG. 8, a second optical unit 570
A pair of pulleys 86 and 8 are respectively attached to both ends.
7 are attached to support shafts 95 and 96 that are independently arranged on a line parallel to the moving direction of the optical unit 57, that is, in a direction along the tension direction of the wire 88. A stable support state can be maintained for a long period of time in a state where no moment acts in a direction perpendicular to the direction and no vibration is generated.

Note that 97 is a connection reinforcing member that connects the free end sides of support shafts 95.96 that rotatably support the pulley lj6.87.

In addition, in order to change the copying magnification as described above, the lens unit 54 and the third optical unit 22, which includes two mirrors 513 and 59 arranged at a 90 degree angle, each have a predetermined amount of That is, for example, focal length f
When using a lens with a diameter of 210, it is necessary to move it approximately as shown in the table below.

However, the direction approaching the third optical unit is (-) and the direction away from the third optical unit is (+). is supported, making it possible to move the lens unit 54 and also to make the third optical unit 60 moveable with a smaller amount of remote movement than this lens unit 54, so that a predetermined copying magnification can be obtained. There is.

In other words, a pair of screw shafts 100 and 101 are rotatably installed in parallel across a movement path of 54.6σ in each unit.
0,101, the third optical unit 6θ is slidably supported by externally fitting slide bushes 103 attached to both ends of the carriage 102.

Further, at one end of the caliper 102, a snow lug 10 is provided which is engaged with the screw shaft 101.
4 is attached, and as the screw shaft loz rotates forward and backward, the third optical unit 60 reciprocates using the screw shaft 101°ZOO as a guide.

The screw shaft 101 is configured such that the driving force of the mirror pivoting pulse motor 105 is transmitted through a set of gears 106 and 107.

On the other hand, one end of the carriage 10g of the lens unit 54 is held by the screw shaft 100 via slide bushes 120, 120, and the slider 121 attached to the lower surface of the other end of the third optical unit 60 is By placing it directly on the carrier 102, it is supported in a slidable manner.

Further, a spiral housing 122 is disposed at one end of the shaft 108 and engaged with the screw shaft 100.
is attached, and is designed to reciprocate as the screw shaft zoo rotates in the forward and reverse directions.

The screw shaft I00 is a lens drive shaft No. 4.
The driving force of the smoke 105 is a set of gears 124, 125
It is intended to be transmitted via.

As the mirror drive lens motor 105 rotates forward and backward, the third optical unit 600 moves a predetermined distance in a predetermined direction, and as the lens drive lens motor 123 rotates forward and backward, the lens unit 54 moves. It will move a predetermined distance in a predetermined direction. At this time, the mirror drive pulse motor 105 and the lens drive pulse motor 12
By changing the cycle of the third drive pulse, the amount of movement per unit time of the third optical unit 60, which requires less movement than the lens unit 54, is set to be smaller than the amount of movement of the lens unit 54. It is in a state. Then, the lens unit 60 and the third optical unit 5
Since the change in focus and magnification for the same amount of movement of the third optical unit 54 is larger, the third optical unit 54 is moved slowly to avoid the adverse effects of inertia, etc., and high positional accuracy can be obtained. .

The developing device 15 has a structure as shown in FIGS. 10 to 16. That is, as shown in FIG. 10, it has a developing roller 2130 as a first developing member and a developing roller 131 as a second developing member, and these developing rollers I30°131 are selectively driven to produce, for example, It is possible to perform black or red development.

Further, the developing device 4 includes a first developing roller 130 .
The developing unit 7) 132 and the second developing unit 133 containing the second developing unit 7) 132 are divided into two, and the first developing unit 132 in the upper stage uses red developer Da, which is rarely used. The lower second developing unit 133
is set to 5 to use the frequently used black developer Db. Note that the developer Da + Db is a two-component developer consisting of toner and carrier.

The first developing unit Z32 that uses the red developer Da is composed of a developing mechanism section 134 and a developer stirring section 135, as shown in FIGS.
130 and 1. A doctor 137 is provided at the sliding contact portion of the developer magnetic brush D@' formed on the surface of the developing roller 130 with the photoreceptor 12, that is, upstream of the development position 136, and regulates the thickness of the developer magnetic brush D11'. and a developing roller 130 provided downstream of the developing stand 136.
A scraper 139 scrapes off the developer magnetic brush D, / on the surface of 0 and guides it to the developer storage section 1311, and a developer stirring body 140, 140 accommodated in the developer storage section 138.
and are housed in a casing 141.

9. The first developing roller 130 is a trap having a magnetic roll 142 and a sleeve 143 fitted over the magnetic roll 142. The magnetic roll 142 has five magnetic pole parts 144&~1
446, the first, third . Fifth magnetic pole part 144m, 1
44a.

144e is the N pole, the second . Fourth magnetic pole portion 144b.

144d is an S pole, and each magnetic pole part 144a to 14
4e is arranged at an angle of approximately 50° to 70°, the third magnetic pole portion 144c facing the development position has a gauss of 700 to 1000 gauss, and the other magnetic pole portions z44m+144b, 144d, 144
m has a magnetic force distribution of 300 to 600 Gauss.

Therefore, in this first developing unit I32,
The rotary sleeve 143 is rotated clockwise in the figure to perform development, which is the so-called advanced mode, and the developer plan Da' held on the surface of the photoreceptor 12 is brought into sliding contact in a direction opposite to the flow of the image on the photoreceptor 12. Especially photoreceptor 12
The electrostatic latent image formed on the image is developed. By reducing the diameter of the developing row 2130, the space from the exposure position to the transfer position is minimized, thereby making the copying machine more compact.

In the present invention, since the diameter of the photoreceptor 12 is 78 mm, the circumference from the exposure position to the transfer position is about 122 degrees centigrade. In order to widen the transfer vertical distance from the development position, that is, the exposure position, it is necessary to further reduce the size of the charging device Z3 and the cleaning device 18, but there is a limit to this.

For the above reasons, the inventors of the present invention have already confirmed that it is possible to install a developing device in which the diameter of the developing roller 130 is 40 m+ or less in terms of space. Also, the first developing unit! 32. It has been confirmed that the height of the second developing unit 133 is limited and must be 120 m or less when the drum diameter is 78 cm. That is, 1st. The second developing unit) 132.7.73 must be made thinner. For this reason, advanced mode developing devices are often used, which are advantageous in terms of space in the height direction and have a small number of poles and are inexpensive in cost. In particular, in the first developing unit 132 installed at the top, the developer opening faces downward, so in the with mode where the developer Da flows from the top to the bottom, problems such as the developer Da spilling out may occur. do. In this respect as well, the upper first developing unit 13
2, the advanced mode is advantageous.

Further, in the first developing unit Z32, the developer magnetic brush Da' on the rotating sleeve 143 is removed by the developer removing means 145. As shown in FIG. 12, this developer removing means 145 simply moves the rotating sleeve 143 in the opposite direction (counterclockwise direction) to that during development.
This is an extremely simple and inexpensive method that removes the particles by rotating them.

The rotating sleeve 143 rotates in the opposite direction when sawing is completed, and the developer D8 is conveyed in the opposite direction. Therefore, all the developer Da on the rotating sleeve 143 is transferred to the doctor blade 137 as shown in FIG. It is stored between and Scree/#139.

In addition, in the case where the magnetic pole part has five poles, the farther apart the first magnetic pole part (carrying pole) 144m and the fifth magnetic pole part (carrying pole) Z44e are, the more efficiently the developer D1 is transported and not transported. can be controlled, so it is desirable that the number of poles be 5 or less.

In addition, an elastic thin plate member (not shown) such as Mylar (trade name) is attached to the scraper 139 with its tip in contact with the rotating sleeve 143 to prevent reverse conveyance of the developer Da. It's getting better.

Further, the reverse rotation operation of the rotating sleeve 143, that is, the removal operation of the developer magnetic brush Da is performed not only after the development operation is completed (after the copy operation is completed) but also after the apparatus is inadvertently stopped. In other words, when the power is turned off or the device suddenly stops due to a paper jam, etc., the optical system of the exposure optical device 14 is then turned on, the paper jam is removed, etc. At the same time as returning to the initial state, reversal is performed again. The configuration is such that the developer Da does not exist on the rotating sleeve 143 at least in the vicinity of the developing position 136 during the "copyable" state, that is, during the resolving period.

If the rotary sleeve 143 is small, with a diameter of about 40 cm or less and a width of about 40 cm or less, the implementation method for controlling the conveyance and non-conveyance of the developer Da is as follows.
In addition to changing the rotation direction of the rotating sleeve 143 mentioned above,
This can also be carried out by rotationally displacing the magnetic roll 142 via a drive source such as a solenoid so that the first magnetic pole portion 144m faces the doctor blade 137 made of a non-magnetic member.

Also, a second development unit that uses black developer Db,)
Z J 3 is as shown in FIGS. 13 and 14,
It consists of a developing mechanism section 146 and a developer agitating section 147, and is located at a sliding contact area between the developing roller 131 and the photoreceptor 12 of the developer magnetic brush Db' formed on the surface of the developing row 2131, that is, from the developing position 148. A doctor 149 provided on the upstream side regulates the thickness of the developer magnetic brush Db', an id 151 that guides the developer Db scraped off by the doctor 149 to the developer storage section 150, and the developer storage section 150. The developer agitating body 152 housed in the developer agitating body 152 is housed in a casing 153.

Further, the developing row 2131 is composed of a magnetic roll 154 and a rotating sleeve 155 that is fitted onto the magnetic roll 154 and rotates counterclockwise in the figure.

In this second developing unit 133, high-speed development is possible (the developing roller 131 is made larger than the first developing roller 130, and the rotating sleeve 155 is made larger than the first developing roller 130).
The image is developed by rotating it counterclockwise in the figure, in a so-called "width mode" in which the developer brush Da' held on the surface of the photoreceptor 12 is brought into sliding contact in a direction that follows the flow of the image on the photoreceptor 12. In particular, ensure sufficient development time and
The electrostatic latent image formed on 2 is developed in a high quality image state.

The magnetic roll 154 has a diameter of 5 mm suitable for the with mode.
The first developing roller 130 has six magnetic pole parts 156a to 156f, which is one more than the first developing roller 130, and the second developing roller has six magnetic pole parts 156a to 156f. 4th. Sixth magnetic pole part 156b.

156d and 156f are N poles; Third. The fifth magnetic pole portions 156m, 156c, and 156a are S poles, and each of the magnetic pole portions 156a to 156f is arranged at an angle of about 50° to 60°, and the fourth magnetic pole portion 15 facing the mirror image standing
6d is 800-1000 Gauss, other magnetic pole part 756m
, 156b, 156a.

156e and 156f have a magnetic force distribution of 400 to 600 Gauss.

Further, in the second developing unit 133, the developer magnetic brush Db' on the rotating sleeve 155 is removed by a developer removing means 157. As shown in FIGS. 13 and 14, the developer removing means 57 consists of a rotary sleeve consisting of a blade 158 made of an elastic member such as urethane rubber, and a blade moving mechanism 159 for horizontally moving the blade 158. 155
By pressing the blade 158 against the zero surface, the developer Db is prevented from being conveyed to the development position 148.

The blade moving mechanism 159 has a structure in which a rack 162 provided on a slider 161 integrated with a blade holder 160 meshes with a pinion 164 driven by a motor 163. Then, the motor 163 is turned in the forward direction.
By rotating the slider 161 in the opposite direction, the slider 161 is moved forward and backward, and the plaid 158 is brought into contact with the surface of the photoreceptor 12 as shown in FIG.
It is designed to be separated from the surface.

Further, the plaid 158 is placed in pressure contact with the photoreceptor 12 between the position of the doctor plaid 149 and the second magnetic pole portion (carrying pole) 156b. This means that placing the second transport pole 156b vertically is the most efficient way to scrape off the developer brush Db', but if the interval is widened, grade 1
58 and the doctor blade 149, the developer Db accumulated during the next copying may be scraped off as the photoreceptor 12 rotates and contaminate the inside of the machine. Therefore, the blade 158 is placed vertically in pressure contact with the developer Db at a position where there is little accumulation of the developer Db and where scraping is efficiently performed, that is, between the doctor blade 149 and the second magnetic pole portion 156b.

Note that I66 and 167 are position detectors that detect the forward and backward positions of the slider 16, and these detection signals are used to stop the motor 163.

After copying is completed, the blade 158 touches the photoreceptor 12 immediately before the rotating sleeve ZSS stops, as shown in FIG.
After that, the rotating sleeve 155 makes more than half a turn and stops, and then the blade 158 separates from the rotating sleeve 155 as shown in FIG. Therefore, at least the developer Db at the development position on the rotating sleeve nib 155 is removed.

Further, the contact operation of the blade 158, that is, the removal operation of the developer magnetic brush Db is performed by the first developing unit 1 described above.
As in the case of No. 32, this is performed not only after the development operation is completed (after the copy operation is completed) but also after the apparatus is inadvertently stopped. In other words, in the case where the power is turned off or the apparatus suddenly stops due to a paper jam, etc., the optical system of the exposure optical device 14 is subsequently turned on, the paper jam is removed, etc. At the same time as the initial state is restored, the blade 15 is turned on again.
8 contact operations are performed.

The configuration is such that the developer Db is not present on the rotating sleeve 155 at least in the vicinity of the developing position 148 during the "copyable" state, that is, during the resolving period.

Moreover, the first. The second developing units 132 and 133 are configured to operate selectively in response to designations from a color designation section (not shown). That is, when red is specified, the first developing unit 1 is
The magnetic brush Da is formed only on the rotating sleeve 143 of the second developing unit 133, and when black is specified, the rotating sleeve 155 of the second developing unit 133 is formed only on the rotating sleeve 155 of the second developing unit 133, as shown in FIG.
A magnetic brush Db is formed only on the top.

When the first developing unit 132 side is designated as 5 to be operated, the first developing roller 1300 rotating sleeve 143 rotates clockwise as shown in FIG.
A developer magnetic blank Da is formed on the surface of the rotating sleeve 1430. Then, the electrostatic latent image previously formed on the photoreceptor z2 is developed with the red developer D&.

When the development of this silent image is completed, the developer removing means 145 operates as described above, and the rotating sleeve 143
rotates in the opposite direction, and at least the developer Da at the development position fil 136 is removed in preparation for the next development operation.

Note that at this time, the developer magnetic brush Db' is not formed in the rotating sleeve 155 of the second developing unit 1330, and even if either of the developing units (132, 133) is specified next, problems such as color mixing may occur. is designed to prevent this from occurring.

Further, when the second developing unit 133 side is designated to be operated, the rotating sleeve 155 of the second developing roller 131 rotates counterclockwise as shown in FIG. A magnetic brush Db is formed. In order to cope with high-speed copying, the electrostatic latent image formed in advance on the photoreceptor 12, whose rotation is controlled at a higher speed than during development by the first developing unit 132, is transferred to the black developer D.
It will be developed in step b.

When the development of this electrostatic latent image is completed, the developer removing means 157 operates as described above, and the rotating sleeve 155
The blade 15g is in pressure contact with the surface of the developer Db, and at least the developer Db at the development position 148 is removed in preparation for the next development operation. Note that at this time, the first developing unit 13
The developer magnetic plan Da′ is not formed in the rotating sleeve 143 of No. 2 either, and next, either of the developing units 132
, 133 is specified, problems such as color mixing no longer occur.

Note that the gloss speed is set high for black copying and low for color (red) copying, thereby improving the image quality of color copying.

Therefore, at the time of black copying, that is, during development in the second development unit 133, the peripheral speed of the drum-shaped photoreceptor I2 is 22.
3 mm/s, 35 sheets/min, A4 horizontal color copying, that is, when developing in the first developing unit 132, the peripheral speed of the drum-shaped photoreceptor I2 is 136 mm/s, 25/min, A4 horizontal speed. The developing roller 130 has a smaller diameter of 38 mm than the diameter 508 of the second developing roller 131, and by ensuring sufficient developing time, a high quality color image can be obtained. Furthermore, black copy, which is frequently used, enables high-speed copying.

In addition, each developing unit 132 configured as described above.
133 has a front cover 17 as shown in FIG.
The developer receiving and conveying section 132a is exposed by opening the opening.

133a protrudes, and these developer receiving and conveying sections 1
Cartridge type developer replenishing devices 171 and 172 are removably attached to the cartridges 32* and 133a. A developer empty detector 17 detects the amount of developer (toner amount) in the developer storage sections 131J and 150.
According to the detection signal from 3.degree. 174 (see FIG. 3), the developer Da and Db are appropriately replenished in an amount commensurate with the consumed amount.

Developer replenishing device 17 on the second developing unit Z33 side
2 is constructed as shown in FIGS. 18 to 20. That is, 175 is a container that stores the developer Da, and a transfer screw 176 at the bottom of the container 175 is rotatably driven to transport the developer Db in the axial direction.
is in a stored state.

Further, at the lower part of one end of the transfer screw 176 of the container 175 located in the developer transfer direction, there is a holder 17 as a mounting section connected to the developer receiving and conveying section 1331.
A fitting protrusion 175m that can be freely inserted into and removed from 7 is formed. A developer discharge port 178 for discharging the developer Db transferred by the transfer screw 176 is formed on the lower surface side of the fitting protrusion 175m.

Further, the holder 177 is connected to the developer receiving and conveying section 133.
It is rotatably attached to the upper surface side of a, and a replenishment port 179 is formed on the bottom surface thereof corresponding to the developer transfer shaft (toner auger) 182 of the developer receiving and conveying section 133m. It is in a state.

Further, the holder 1 is attached to one end of the transfer screen 176.
77 has a connecting portion 176a that protrudes from the end surface and connects to the driving force lug ring 181 of the driving device 180.

A developer discharge port 17 is provided on the lower surface side of the fitting protrusion 175m.
A lid 183 is provided to be slidable to open and close the lid 8. On the other hand, on the holder 177 side, there is a recess 1 as a retaining portion that engages with a retaining protrusion Z133m formed on the lid body 183.
84 is formed, and the fitting protrusion 175m is inserted into and removed from the holder 177 as shown in FIG. 20(a).

As shown in (b), a lid 183 slides to open and close the developer discharge port 180.

Further, as shown in FIGS. 17 and 18, the drive device 180 includes a gear 18 integrated with the coupling 181.
6, a worm gear 187 that meshes with this gear 186, and a motor 188 that drives this worm gear 187, and is attached to a movable pace 190 that is slidable in the direction of arrow F in FIG.

Then, the motor 188 is driven for a predetermined period of time in response to the detection signal from the developer embossing detector 174, and the transfer screw 176 is rotated.

As a result, the developer Db in the container 175 is sent to the developer discharge port 178 side, and is sent to the replenishment port 179 of the developer receiving and conveying section 133a.

Next, the replenishment port 179 of the developer receiving and conveying section 133a
The developer Db fed into the developer container 150 is carried upward into the developer accommodating portion 150 as the developer 1820 rotates.

On the other hand, developer discharge ports 201a to 201a are provided at the bottom of the developer guide OO surrounding the developer transport shaft 182.
The developer stirring body 1 provided in the developer storage section 150 is provided with a certain interval La to Lg 201h.
52 in the axial direction. The interval La % Lg between the developer number outlets 201tr to 201b becomes narrower in the developer transport direction, and the distance between the developer discharge ports 201a to 201
The opening area of 1h is larger on the side in the developer transport direction, so that the developer Db is uniformly distributed.

In addition, when removing the cartridge-type developer replenishing device 172, such as when the developer Db runs out, first move the drive device 180 to the right in the state shown in FIG. Connection part 1 of screw 176
The engagement operation between 76m and coupling 181 is released.

Next, after the entire developer replenishing device 172 is rotated toward the front about the holder 172, the fitting protrusion 17511 is pulled out from the holder 177 by pulling toward the front.

Furthermore, when installing a new developer replenishing device 172, the above procedure can be reversed.

On the other hand, the developer replenishing device 171 on the first developing unit I32 side has approximately the same configuration as the developer replenishing device 172 on the second developing unit 133 side, as shown in FIGS. 18 and 19. There is. That is, 210 is developer D
This container 210 stores a transfer tube IJ, -211 in the bottom of the container 210, which is rotated to transfer the developer Da in the axial direction.

Further, at the lower part of one end of the transfer screw 211 of the container 210 located in the developer transfer direction, there is a holder 21 as a mounted portion connected to the developer receiving and conveying portion 133mK.
A fitting protrusion 210a that can be freely inserted into and removed from 2 is formed. A developer discharge port 213 for discharging the developer Da transferred by the transfer screen -211 is formed on the lower surface side of the fitting protrusion 210a.

Further, the holder 212 is connected to the developer receiving and conveying section 133.
It is rotatably mounted on the top side of a, and on the bottom side there is a replenishment port 214 corresponding to between the developer agitating body 140 and the developer agitating body 140, which is formed of a spiral shaft.
has been formed.

Further, the holder 2 is attached to one end of the transfer screw 211.
12 and has a connecting portion 211m that protrudes from the end face of the drive device 215 and connects to the driving force horn ring 216 of the driving device 215.

A developer discharge port 21 is provided on the lower surface side of the fitting protrusion 2101.
A lid body 217 is provided to be slidable to open and close 3.

On the other hand, on the holder 212 side, a recess 218 is formed as a retaining portion that engages with a retaining protrusion 217a formed on the lid body 217.
During the insertion/removal operation of 10 m, the lid body 217 slides to open and close the developer discharge port 213 in the same manner as described above.

Further, as shown in FIGS. 17 and 18, the drive device 215 includes a gear 21 integrated with the coupling 216.
9, a worm gear 220 that meshes with this gear 219, and a motor 221 that drives this worm gear 220, and is attached to a movable pace 222 that is slidable in the direction of arrow G in FIG.

Note that 223 shown in FIG. 18 is a support member that supports the side end surface of the container 210.

Then, the motor 221 is driven for a predetermined period of time by the detection signal from the developer embossing detector 173, and the transfer stopper IJ-211 is rotated.

As a result, the developer Da in the container 210 is sent to the developer discharge port 213 side, and is sent to the replenishment port 214 of the developer receiving and conveying section 132&.

Next, the replenishment port 214 of the developer receiving and conveying section 132a
The developer Da fed into the developer storage section 138 is uniformly distributed to the developer storage section 138 by developer agitators 140, 140 each having a spiral shaft.

In addition, when removing the cartridge-type developer replenishing device 171, such as when the developer Da runs out, first,
By displacing the drive device 215 rightward in the figure in the state shown in FIG. 18, the engagement between the coupling portion 211-a of the transfer screw 211 and the coupling 216 is released. Next, the entire developer replenishing device 171 is placed in the holder 21.
After rotationally displacing the fitting protrusion 210m to the front side about 2, the fitting protrusion 210m is pulled out from the holder 212 by pulling the fitting protrusion 210m to the front side.

Furthermore, when installing a new developer replenishing device 171, the above-mentioned procedure can be reversed.

Further, as shown in FIGS. 22 and 23, the developer Db
A stirring blade 225 is rotatably housed in the container 175 containing the developer Db, and a transfer screw 176 is attached to the peripheral edge of one end surface of the stirring body 225 to transfer the developer Db to the developer discharge port 178 side. A plurality of claws 227 . . . are provided in a protruding manner to engage with the attached sedge location 226 . and,
The agitating blade 225 rotates as the transfer screw 1760 rotates, thereby preventing the developer Db in the container 175 from clumping or shifting, thereby ensuring that the developer Db can be reliably supplied without remaining.

On the other hand, similarly, inside the container 210 containing the developer Da,
The stirring blade is housed, and is configured to similarly stir the developer Da in the container 210.

Note that 228 shown in FIG. 17 is a collection box for collecting the developer scraped off by the cleaning device 18, and can be easily removed by opening the front cover 170. Further, 229 is a mognet catch for holding the front cover 170 by suction.

Next, with reference to FIGS. 24 to 28, the automatic paper feeder 2
The configuration of 0 will be explained.

As shown in FIG. 28, paper feed cassettes 7, 8, and 9 containing sheets of paper P are each mounted on the upper surface of the base 240 via guides (not shown) so as to be freely insertable and removable.

As shown in FIG. 25, each of these paper feed cassettes 7, 8, 9 has guides 241, 242m that regulate the rear end of the paper P and its both sides.

242b, and a paper support plate 243 that supports the paper output end side.
It has a configuration with.

The paper support plate 243 is supported so as to be able to swing freely by engaging a groove formed on the bottom surface of the cassette main body 244 with the end opposite to the paper output side thereof. Further, the paper support plate 243 is formed with through holes 245, 245, and the paper support plate 243 at the bottom of the cassette body 244 is
An opening 246 is formed at a position corresponding to .

The cover 10 of the paper feed cassette 70 in the uppermost stage constitutes a manual paper feed tray 11 as shown in FIG. guide members 247, 247 are provided. These pair of guide members 247, 247 are attached to the cover 10 as shown in FIGS. 27 to 29, and when either guide member 247 is moved, the other guide member 247 is moved in conjunction with the guide member 247. It is supposed to be done.

FIG. 27 shows the cover 10 viewed from the back side, and a pair of racks 249 and 249 are arranged symmetrically around a rotatably arranged binion 248 at the center in the width direction of the cover 10. One end meshes with the pinion 248, and the other end is fixed to the corresponding guide member 247 and 247 via pins 250 and 251, respectively.

Therefore, when one guide member 247 is moved along the width direction H, the other guide member 247 interlocks with this and slides toward each other or rather than away from each other. i.e. pinio/248 and rack 249
This constitutes interlocking means for interlocking both guide members 247.

As shown in FIG. 28, the bottles 250, 251 are inserted into the corresponding guide slots 252 at intervals, so that
The rack 249 is thereby guided to move along the width direction H. In addition, on both sides of the pinion 248, guide pins 256 are further provided protruding from the cassette body IO, and these guide pins 256 are attached to the rear surface of the corresponding rack 248 to prevent the rack member 249 from coming out of engagement with the pinion/248. Holds guidance.

In the figure, reference numeral 257 denotes a guide reinforcing plate attached to the back surface of the cover 10 by appropriate means, and is provided in the width direction along the running path of the rack 249 which constitutes the interlocking means. This guide reinforcing plate 257 also has a long hole formed in a state that matches the long hole 252 of the cover 10.

Also, the pivot shaft portion 2 rotatably supports the binion 248.
58 is provided protruding from the back surface of the cover 10, as shown in FIG. ing. The left and right pair of cut and raised tongue pieces 259m and 259a of the braking member 259 are bent to form the pinion 248.
It is in a state of elastic frictional engagement with the outer peripheral edge, and
Both ends 259b, 259b of the braking member 2590 are bent at right angles, and notches (not shown) formed therein are engaged with the guide pins 256, 256. Therefore, -nion 248 is tongue piece 259m of braking member 259,
259a applies a slight braking action to the rotational movement, thereby preventing blind movement such as excessive rotation. Therefore, the entire movement of the interlocking means is also subjected to a light braking action, so that when the guide members 247° 247 are moved, it is possible to prevent blind movement of each moving member due to inertia or positional shift due to vibration.

In addition, each paper support plate 243 of each paper feed cassette 7.8.9
is a support plate push-up mechanism 26 provided in each cassette mounting section.
The uppermost sheet P is selectively pushed up by the rotating operation of the push-up lever 264 of No. 3, and is pressed with appropriate force against a take-out roller (sheet feeding roller) 265 as a take-out means.

The support plate push-up mechanism 263 has a configuration as shown in FIG. 30. That is, 266 is a shaft rotatably supported by a bearing (not shown), and this shaft 266 has approximately 1
The push-up lever 264 and the operating lever 267 are attached with a phase shift of 80 degrees. Further, a spring 268 is connected to the operating lever 267, and the lower surface of the free end thereof is biased so as to be in constant contact with the circumferential surface of the eccentric cam 269.

The eccentric cam 269 sequentially meshes gears 270°271.2
The driving force of the motor 274 is transmitted through a gear mechanism 273 consisting of 72. And motor 2
As the eccentric cam 269 rotates, the maximum eccentric part of the eccentric cam 269 opposes the actuating lever 267, so that the actuating lever 267
is pushed up against the biasing force of the spring 268 (the state shown by the solid line in Fig. 30), and the least eccentric portions face each other, so that the actuating lever 267 is pulled by the force of the spring (Fig. 30). The state shown by the two-dot chain line) is reached.

Accordingly, with this movement, the push-up lever 264, which is in an integral relationship with the operating lever 267 via the shaft 266, is also rotated to the state shown by the solid line or the two-dot chain line in FIG. The sheets P... accumulated on the take-out roller 243 may be separated from or come into contact with the take-out roller 265.

In addition, as shown in FIG. 24, rollers 289 and 290 that roll into contact with each other serve as separation means 288 that separates the second and subsequent sheets of paper P that has been picked up and prevents them from being taken out. is provided. These rows 2289 and 290 are constructed as shown in FIG. That is, 291 in the figure is a motor, and this motor 291 is in a state of meshing with gears 293 and 294 via a gear 292.

The gear 293 is configured to be interlocked with the roller 289 via a shaft 295, and the gear 294 is interlocked with the roller 29 via a shaft 297 having a spring clutch 296 in the middle.
It is configured to work in conjunction with 0.

゛Also, the spring clutch 296
9,290 is set to slip when the force at the contact portion exceeds Ta. Further, if the frictional force between the rollers 289 and 290 is Tb, it is set to be Ta)Tb,
Roller 289 is adapted to rotate according to roller 290.

In addition, the frictional force between the paper P and the paper P is Tf, and the roller 26
If the frictional force between 5 and paper P is Tr, generally low 22
65 is Tr)Tf because it is molded from a material with a high coefficient of friction such as rubber. And Ta is Tr ) Ta
) Tf.

Thus, during paper feeding standby, the paper P is in a state separated from the take-out roller 265, as shown in FIG. 23(-). During paper feeding, as shown in FIG.
After being brought into rolling contact with the sheet P, the uppermost sheet P is taken out as the take-out roller 265 rotates and is sent between 289 and 290 forming the separating means 288.

At this time, the second and subsequent sheets of paper P that are taken out by adsorption to the topmost paper P are moved to the roller 2 as shown in FIG. 23(c).
The sheets P are separated by the reverse rotation operation of 90, and only the uppermost sheet P is taken out.

This means that when paper P enters between rollers 2B9 and 290, roller 289 moves in the direction of arrow J due to paper Pt1-Tr>Tf.
In addition, the roller 290 and the paper P... are Tr) Ta
23(d), the push-up lever 264 is lowered again as shown in FIG. 23(d).
It will wait in the state shown below.

As shown in FIG. 33, the upright position corresponding to the bottom side of the paper feed cassette 7°8.9 and the upright position corresponding to the paper conveyance path immediately before the separating means 288 are each connected to a control unit (not shown). reflective optical sensor 300 as a paper detector,
301 is provided. And these two sensors 30
A sheet no-paper detecting means 302 is configured which determines that there is no paper based on the sum of the no-paper detection signals of 0°301.

When the paper P is placed on the paper support plate 243 as shown in FIG.
As shown in FIG. 33(b), when the last sheet separated by the roller 290 is held between the rollers 289 and 290, it corresponds to the bottom side of the paper feed cassette 7 (8, 9). This cannot be detected by the sensor 300 installed at the position where the separation means 288 is located, but it is possible to detect this by the sensor 301 installed at the position corresponding to the paper conveyance path immediately before the separating means 288. Therefore, even though there is paper P,
This prevents a determination that the paper is out of paper.

In addition, a reflective optical sensor 300.3 is used as a paper detector.
By using 01, paper P can be detected in a non-contact state, and compared to using a transmission type optical sensor, it has the advantages of being less affected by external light and being easier to install. There is.

Further, as shown in FIG. 24, the paper P that has passed through the separating means 288 is held by the roller 24 of the registration roller pair 24 that is stopped.
After being brought into contact with the contact portion between m and 24b and the inclination (skew) of the tip thereof corrected, it is sent to the image transfer section 21 in synchronization with the image forming operation on the photoreceptor 12.

Also, the uppermost separation means 288 and the reso roller pair 24
A pair of transfer rollers 305 consisting of rollers 305 and 306 is disposed between them.

The take-out rollers 265..., the transfer rollers 305b of the two pairs of transfer rollers 305, and the rollers 24th of the pair of registration rollers 24 are configured to be driven via a power transmission system 306 shown in FIG. In other words, 3 in the figure
07 is a pulse motor as a driving means, and a driving gear 3011 attached to the driving shaft of this motor 307 is meshed with a gear 310 via an intermediate gear 309. A gear 310 is attached to the shaft of one of the rollers 24a of the pair of shaft/sys rollers 24 via a one-sided clutch 311.

Further, a Sugerocket 312 is integrally attached to the intermediate gear 309, and the driven gear 312 is connected to the intermediate gear 309 via a chain 313.
14 and a sprocket 315 that is integrated with the sprocket 315.

The sprocket 315 is attached to the shaft of the transfer roller 305b via a one-sided clutch 319, and a gear 314 is attached to the shaft of the transfer roller 305b. The gear 314 further includes an intermediate gear 316,
317 are successively valved to mesh with a gear 318 attached to the shaft of the take-out roller 265.

Therefore, when the motor 307 rotates forward (in the direction of the solid line arrow), the one-way clutch 311 is turned off, and the one-way clutch 311 is turned off.
When the switch 315 is turned on, the take-out roller 265 and the roller 305b are driven, and the roller 24th is stopped because no power is transmitted to it. Also, when the motor 307 rotates in the reverse direction (in the direction of the dashed arrow), one side cracks.

clutch 311 is on, one-way clutch 315 is off, and only roller 24m is driven, and roller 305b is driven.
, 265 are in a stopped state with no power being transmitted by the action K of the one-sided clutch 319.

In this way, the take-out row 2265 and the reno roller pair 2 are rotated in the forward and reverse directions of the pulse motor 307 as a driving means.
The configuration is such that one of the rollers 24m of the rollers 4 is selectively rotated.

In addition, the uppermost paper feed cassette mounting section is equipped with a manual feed tray that sequentially takes out the sheets of paper P set in the manual feed tray 1 one by one and feeds them to the separation means side through the take-out roller 265 section. A roller 321 is provided. The manual feed roller 32 and take-out roller 265 are shown in FIGS. 24 and 3.
The roller approaching/separating means 322 shown in FIG. 5 is configured to freely approach and separate from the paper conveyance path, and is configured to separate the take-out roller 265 from the paper conveyance path at least during manual paper feeding.

That is, the spindle 265 of the take-out roller 265 is attached to and supported by the free ends of arms 323, 323, which are rotatable about the spindle 289a of the roller 289 of the separation means 28B. In addition, the manual feed roller 321 is
The arm 324 is rotatable around the support shaft 265a of No. 5 as a fulcrum.
Attachment is supported at the free end of 324 degrees.

Furthermore, locking protrusions 342a are integrally provided at the free ends of the arms 324, 324 in a state that they are perpendicular to each other, and these locking protrusions 342&.

342a is a lever 327.32 that is rotatably supported around the support shaft 325 and attached to the nine-swivel member 326;
7 and extends upwardly from the free end thereof.

The rotating member 326 is always urged counterclockwise by a spring 328 in the state shown in FIG. Part 324 & , 3
24a is in a lifted state.

Further, the rotating member 326 includes a plunger type solenoid 3.
29 plungers 329a are connected via a connecting member 330, and the rotating member 326 is connected to the spring 32.
It is configured so that it can be rotated by the biasing force of 8.

Note that 331 in FIG. 24 is a manual paper feed switch arranged in front of the manual feed roller 3210. Also, the 35th
As shown in the figure, a sprocket 332 is attached to the spindle 265a of the take-out roller 265, and a sprocket 333 is attached to the spindle 321a of the manual feed roller 321.
They are linked together via a chain 334.

When the paper P is placed on the paper feed table 11, the manual paper feed switch 331 is turned on, and the on solenoid 329 of the start getter 30 becomes Oh. Then, the rotating member 326 is rotated against the biasing force of the spring 328, and the manual feed roller 321 is lowered, and in conjunction with this movement, the take-out roller 265, which is a perfect circular roller, is moved upward away from the paper conveyance path. Displace.

Then, when the paper P is sent to the separating means 288, the solenoid 329 is turned off, the manual feed roller 321 is raised, and the take-out roller 265 is accordingly lowered.

At this time, the push-up lever 264 that pushes up the paper support plate 243 of the paper feed cassette 7 is in a lowered state, and the paper P
is separated from the take-out roller 265.

Next, the fixing device 25 will be explained with reference to FIGS. 36 to 39.

The fixing device 25 is roughly divided into an upper roller unit 336 and a lower roller unit 337.

The upper roller unit 336 has a heat source (not shown) inside.
The lower roller unit has a structure in which a heat roller 338 whose outer surface is coated with Teflon is attached to a bracket 340 rotatably supported via a support shaft 339. 337 has an elastic surface...
A pressure roller 341 made of, for example, a rubber roller.
is attached to a bracket 343 that is always urged upward by the urging force of an urging member such as a compression spring 342. The bracket 343 is connected to the guide shaft 344, 3
It has elongated holes 345, 345 through which the elongated holes 44 are inserted, and can move up and down within the range of the elongated holes 345.

A movable frame 346 is provided near the free end side of the bracket 340 of the upper roller unit 336. The movable frame 346 is a part of the frame of the upper unit, which is rotatably provided so as to be separated from the lower unit almost at the paper conveyance path 23 of the copying apparatus main body 4. As shown in FIG. 36, when the upper unit is superimposed on the lower unit, the movable frame 346 is in contact with the upper surface of the free end side of the bracket 340, and the heat roller 338 is attached to the compression spring. The pressure row 23 resists the urging force of 342.
41 is brought into contact with the pressed down state, and a predetermined contact pressure is obtained.

In addition, the paper conveyance path 2 is
3, when the upper unit is separated from the lower unit in order to open W! , 37
As shown in the figure, the bracket 340 is configured to be able to rotate by a maximum of about 95 degrees using the support shaft 339 as a rotation fulcrum. In addition, with such a configuration, H-)o-53
sg and the pressure roller 341 can be easily replaced.

Furthermore, as shown in FIG. 36, the lower end of the compression spring 342 that biases the bracket 343 supporting the pressure roller 341 upward, that is, so as to apply pressure to the heat roller 338, is movable up and down. The first female type Sufu IJ,
-347, this first female screw 34
7 and the second male screw 348 to connect the ear 34.
The first female screw 347 is moved up and down by being rotated by the stepping motor 349 through the stepping motor 349 and 348b, thereby varying the working length t of the compression spring 342, thereby changing the length of the heat roller 338 and the pressure roller 34.
The load between 1 and 2 can be set according to the process speed of each mode. Note that the pressure roller 341 described above
In some cases, a heat source is housed inside.

Incidentally, in this case, it is also necessary to directly increase the per-copy speed and roller load in various conventional image recording apparatuses A, B, C, D, and E of other companies, as shown in FIG. 38, for example. Therefore, in order to prevent fusing failure, it is necessary to consider the fusing performance in the mode where the process speed is maximum and set the load high according to this maximum speed. As shown in Figure 39, when the process speed is slowed down, the rate of wrinkling tends to increase as the speed becomes slower when the pressure is kept constant.To prevent this, the process speed If the load is decreased along the straight line of the graph shown in FIG. 38, for example, the process speed v (v
If we drop 3〉v2〉vl>vo) from vl to V(1,
The paper wrinkle occurrence rate J increases from Jo to Jl, but if the fixing pressure is reduced from po to Pl at the same time, the paper wrinkle occurrence rate JG does not change, so it is possible to keep the paper wrinkle occurrence rate low. The point is that the minimum value of the load (fixing pressure) that can obtain the minimum fixing performance at a certain process speed can be set as the optimum value for that process speed with less paper wrinkles. This is what has become.

Next, the paper P ejected from the paper ejection section 22 of the image forming apparatus 1 configured as described above is received as necessary, and then returned to the image recording apparatus 1 in the same state or in a reversed state.
The configuration of the direction changing conveyance device 2 that feeds the image to the image forming section will be explained with reference to FIGS. 40 to 44.

As shown in FIG. 40, this direction conversion conveyance device 2 is composed of a unit independent from the image recording device 1, and also serves as a storage stand on which the image forming device I is removably placed.

This direction conversion conveyance device 2 is a discharge section 2 of an image forming apparatus 1.
2, a guide means 350 is provided near the guide means 350 for introducing the ejected paper P as necessary; a carry-in path 351 for carrying in the paper P guided by the guide means 350; a temporary stacking section 352 that temporarily stacks the sheets P that have been collected, a take-out means 353 that sequentially takes out the sheets P accumulated in the temporary stack 352 one by one, and a multiplex image formed on the sheets P taken out by the take-out means 353. A first conveyance section 355 that guides the sheet to the paper introduction section 354 as an image recording body introduction section of the image forming apparatus 1 without changing its leading edge direction, and a first conveyance section 355 that is branched from this first conveyance section 355 are provided. In order to form a double-sided image on the sheet P taken out by the taking out means 353, the conveying direction is changed so that the trailing end becomes the leading edge, and the second conveying section guides the sheet P to the sheet introducing section 354 of the image forming apparatus 1 again. 356 and the paper P taken out by the take-out means 353 provided at the branching part between the second transport section 356 and the first transport section 355.
and the guiding means 350 (by means of a multiplexed, double-sided switching signal from the mode switching button 33 as an operation section of the image forming apparatus I).
Drive means 358, 359 for switching the one-distribution means 357, etc.
It has a configuration that has the following.

The guide means 350 is connected by a support shaft 361 to a rotatably provided gate 362.
are the paper ejection section 22 and the paper ejection roller pair 3 of the image forming apparatus I.
63 to the paper output tray 364 and the carry-in path 366 to the temporary stacking section 352, and is driven by the driving means 358 to selectively guide the paper P. It has become. That is, the r-t 362 is always urged in a predetermined direction by a spring 367, and normally the carry-in path 366 is "closed" and the linear conveyance path 365 is "open". Further, a solenoid 369 is connected to the r-t 362 via a connecting member 378, and if necessary, the solenoid 369 is connected to the input path 362.
The gate 362 can be rotated against the biasing force of a spring 367 in order to open the linear conveyance path 365 and close the linear conveyance path 365.

Further, the carry-in section 366 includes a first pair of conveying rollers 37Q.
1 Second conveyance roller pair 371, third conveyance roller pair 37
2 is arranged to forcibly feed the paper P to the temporary stacking section 352. As will be described later, the third pair of transport rollers 372 is configured such that the receiving and discharging position of the paper P is movable with respect to the feeding direction of the paper P.
Regardless of the size, the tip thereof is configured to be compatible with the take-out means 353 provided corresponding to the end side of the temporary accumulation section 352 in the take-out direction.

Further, the temporary stacking section 352 is constituted by the upper surface portion of the side plate 373, and the actuator 374a of the sheet detecting means 374 faces the central portion thereof.

The take-out means 353 includes a take-out roller 377 held at the free end of an arm 376 that is pivotally supported via a support shaft 375.
The take-out roller 377 is configured to be displaced upward when the paper P is accumulated in the temporary accumulation section 352 so as not to interfere with the accumulation of the paper P.

That is, a protrusion 376a is formed on the pivot end side of the arm 376 and comes into contact with a lever 378 that rotates using a solenoid 378 as a drive source.
The r on J action of 8 causes the take-out roller 377 to displace the protrusion 376a upward as shown by the solid line in FIG.
As shown by the two-dot chain line in FIG. 7, it moves downward due to its own weight and rolls into contact with the sheets P accumulated in the temporary accumulation section 352.

In addition, a pair of conveying rollers 380 consisting of rollers 380a and 380b is provided in the paper take-out direction of the take-out means 353 configured in this manner. It is designed to be sent.

Next, the configuration of the direction changing portion of the paper P taken out from the first temporary stacking section 352 and fed in via the pair of transport rollers 380 will be described with reference to FIG. 41.

That is, the roller pair 380 as the first conveying means
a first conveyance path 382 that conveys the paper P, and a second conveyance path 384 that is provided in communication with the first conveyance path 382 and includes a pair of conveyance rollers 383 as a second conveyance means. , a third conveyance path 386 that branches from the terminal end of the first conveyance path 382 and is provided with a pair of conveyance rollers 385 as a third conveyance means, and a second conveyance path 386 that is joined to the third conveyance path 386. A fourth branch branched from the base end of the conveyance path 384.
The structure has a conveyance path 387.

Furthermore, the first conveyance path 382 and the third conveyance path 386
The paper P conveyed through the first conveyance path 382 is transferred to the second conveyance path 384 by the conveyance roller pair 380 provided at the branching point between the
Alternatively, a first guide means 388 that selectively guides the third conveyance path 386 and a second conveyance means 383 provided at a branching point between the second conveyance path 384 and the fourth conveyance path 387 The paper P that has been reversely fed through the conveyance path 383 is transferred to the fourth
A second guide means 389 for guiding the paper to the conveyance path 387 side is provided, and constitutes the sorting means 357.

Further, the second conveyance path 384 includes a first conveyance path 38
2 to the second conveyance path 384 reaches a predetermined position, and controls the conveyance roller pair 383 to reversely convey the sheet P.
0 is set.

And the above-mentioned 1. By switching the second guide means 388 and 389, the sheet P conveyed through the first conveyance path 382 can be conveyed without changing its leading edge in the conveying direction, or the trailing edge in the conveying direction becomes the leading edge side. The configuration is such that the conveying direction can be changed to , and the paper can be fed into the paper introduction section 354 of the image forming apparatus 1 again.

In addition, the above-mentioned No. 1. The second guide means 388°389 is
A plunger 39 of a plunger type solenoid 392 is pivotally supported via a support shaft 391 and serves as a driving device.
The solenoid 392 is turned on.

The OFF operation causes a rotational displacement as shown by a solid line or a two-dot chain line in FIG.

Next, the operation during double-sided copying will be explained.

(a) First, operate the mode change switch 33 on the operation panel 6 to specify "duplex mode" and use separate operations to set the number of sheets, exposure, magnification, etc., and then press the start switch (
Press 30.

(b) The solenoid 369 of the idle means 350 is pulled, and the copied paper P is guided to the direction changing conveyance device 2.

(C) One-sided copied paper P is temporarily stored in the stacking section 352
are accumulated in

cd) Solenoid 396 of guide means 350 returns.

(,) Replace the original, set exposure, etc., and press start button 30.

(f) Retrieval means 35 provided in the temporary accumulation section 352
30 solenoid 378 is pulled, and the take-out roller 377 is lowered.

(g) The take-out roller 377, the pair of conveyance rollers 3801 which also serves as separation means, and the pair of conveyance rollers (sui, tipak roller pair) 383 rotate.

(h) When the leading edge of the paper P has sufficiently reached the pair of transport rollers 380, the take-out roller solenoid 378 returns and the take-out roller 377 rises.

(1) The transport roller pair 380 stops when the leading edge of the paper P reaches the transport roller pair 383 sufficiently. (However, the conveyance roller pair 380 is rotated by the paper P until the rear end of the paper P pulled by the conveyance roller pair 383 is separated from the paper P with a one-way latch and a chi.) (j) The rear end of the paper P When the sheet passes through the paper detecting means 390, the conveying roller pair 383 reverses, the solenoid 392 of the sorting means 357 is pulled, and the conveying roller pair (feeding roller pair) 385 rotates.

(k) The leading edge of the paper P is the image transfer section 21 of the copying device 1
When the pair of conveying rollers 383 and 3135 reach the pair of aligning rollers 24 located before zero, the pair of transport rollers 383 and 3135 stop and align the paper P.

(1) When the paper P is sent to the image transfer unit 21 and the trailing edge is separated from the sorting means 357, the sorting means 3570
Solenoid 392 returns.

(However, rollers 3B5m and 3 of the conveyance roller pair 385
85b has a one-way latch and is rotated by the paper P pulled by the pair of aligning rollers 24. ) (e) With the sorting means 357 in the returned state, the paper P with one-sided copies in the temporary stacking section 352 is used up (f
) to (1) will be repeated.

Next, the double copy/temporary operation will be explained.

(,) First, operate the mode change button 33 on the operation panel 6 to specify "double mode" and use separate operations to set the number of sheets, exposure, magnification, etc., and then start the switch (
Print gettan) Press 3°.

(b) The solenoid 369 of the guide means 350 is pulled, and the copied paper P is guided to the direction changing conveyance device 2.

(c) The sheets P on which one-sided copies have been made are accumulated in the temporary accumulation section 352.

(d) Solenoid 396 of guide means 350 returns.

(,) Replace the original, set exposure, etc., and press start button 30.

(f) Retrieval means 35 provided in the temporary accumulation section 352
No. 3 solenoid 378 is pulled, and the take-out roller 377 is lowered.

(g) The solenoid 392 of the sorting means 357 is pulled, and the -take-out port-ra 377, the conveying roller pair 380 that also serves as the separating means, and the conveying roller pair (feed roller pair) 385 rotate.

(h) When the leading edge of the paper P has sufficiently reached the pair of transport rollers 380, the take-out roller solenoid 378 returns.
The take-out roller 377 rises.

0) The transport roller pair 380 stops when the leading edge of the paper P sufficiently reaches the transport roller pair 385.

(However, the transport roller pair 31JO has a one-way latch and is rotated by the paper P until the trailing edge of the paper P pulled by the transport roller pair 385 separates.) (j) When the leading edge of the paper P reaches the copying device Image transfer section 21 of l
When reaching the pair of aligning rollers 24 located in front of the conveyance roller pair 385, the pair of conveying rollers 385 stops, aligns the paper P, and then sends the paper P to the image transfer section 21.

(k) With the guide means 350 in its returned position, the operations of (f) to (j) are repeated until there are no more single-sided copied sheets in the temporary stacking section 352.

Furthermore, the paper P ejected from the paper ejection section 22 of the image forming apparatus 1 is received power as needed, and the image is transferred again as the image forming section of the image recording apparatus I in the same state or in the reversed state. In the direction conversion conveyance device 2, which is configured to be able to form multiple or double-sided images on the sheet P, the sheet P is guided to the section 21 as shown by the two-dot chain line in FIG. A member located on one side (lower side) of the P passage section is configured to be freely displaceable outward (lower side) to open the paper passage path.

That is, the lower guide plates 400m of the guide plates 400 & 400b forming part of the carry-in path 366, the lower rollers 371m of the pair of transport rollers 371m and 371b, the guide plate 373 forming the temporary stacking section 352, and the lower guide plate 400m of the guide plates 400 & 400b forming a part of the carry-in path 366, the lower roller 371m of the pair of conveying rollers 371m and 371b, the guide plate 373 forming the temporary accumulation section 352, and the first. The lower guide plate 4o1 and the lower roller 380m of the pair of conveyance rollers J817a*JIIOb constitute the second conveyance path 382°383.

Lower roller 383a of transport roller pair 383a, 383b
are rotatably provided on the negative side of the conveyance direction of the paper P and are attached to a support frame 402, and can be simultaneously displaced outward in order to open the paper passage path as the support frame 402 is displaced. The structure is as follows.

Also, on the free end side of the support frame 402, there are holding means 403 and 403 for holding the support frame 402 in a predetermined state.
These holding means 4'Oj, 40
By operating J, the paper transport section can be opened, making it easy to deal with paper jams and the like.

Further, as shown in FIGS. 42 to 44, a carrying means that receives the sheets P that are sequentially conveyed and sends them to be stacked in the temporary stacking section 352 is movable in the direction in which the sheets P are fed. There is.

That is, the carrying-in means is composed of the conveying roller pair 372 having a driving roller 2372a as a first conveying roller and a driven roller 372b as a second conveying roller.

The drive roller 372a has a slit 40 as a guide section.
The driven roller 372b has a supporting shaft 407 which is movably supported horizontally by holding bearings (butches) 406 and 406 at 5 and 405.
The paper P is pinched and conveyed between the drive roller 372a
The drive roller 3 is provided so as to be in constant rolling contact with the
It is configured to be movable integrally with 72a. The slits 405, 405 as the guide portions are formed by a pair of side frames 408, 40 facing apart and sandwiching the paper conveyance path.
13, respectively.

Further, the bearings 406, 406 held by the slots 405, 405 are positioned on the paper by means of positioning means 409, 409 provided on the outside of the frame 408, 40g.
It is designed to be fixed at a predetermined position depending on the size.

Each positioning means 409 is provided along the movement path of the bearings 406, 406, as shown in FIGS. The structure includes a lever 411 as a vertical positioning member having a length of .410. This lever 411 has one end rotatably attached to the frame 408 via a shaft 412, and a free end serving as a biasing member that constantly biases the concave portion 410 to fit into the bearing 406. The spring 413 is in a connected state.

42 and 44 is a movable frame that holds the bearings 406, 406 and moves together with the drive roller 37211, and 415 is attached to the movable frame 414 and moves the driven roller 372b. This is a leaf spring that biases the drive roller 372!1 side.

Therefore, when setting the transport roller pair 407 for feeding the paper P to the temporary stacking section 352 at a position corresponding to the size of the paper P, both levers 411 are rotated against the biasing force of the spring 413. Movable frame 41 in the state
4 and place the bearing 406°40 in the predetermined recess 410.
6 should be fitted. In this way, the transport roller pair 407 can be moved extremely easily to a position that matches the size of the paper P without using tools such as a screwdriver.
The sheets P can be stacked in the temporary stacking section 352 in an orderly manner so that they can be taken out.

Further, as shown in FIG. 45, if necessary, a large capacity paper feeder 420 that stores a large amount of paper P instead of the paper feed cassette 9 at the lowest stage may also be used instead of the paper ejection tray 364 for collation. A device (sorter) 421 can be attached.

The large-capacity paper feeding device 420 has a structure in which the movement of an elevator plate 424 that can be raised and lowered is controlled by a lifting means 423 using a motor 422 as a driving source so that the uppermost sheet P is always in rolling contact with the take-out row 2425. As the take-out row 2425 rotates, the topmost paper P
are taken out sequentially. Further, the taken out paper P is transferred to a guide plate 426 provided in the transport section 420m,
427 to the take-out roller 265 disposed in the cassette loading section, and then to the pair of aligning rollers 24 via the separating means 288.

On the other hand, as described above with reference to FIG. 33, a reflection type optical sensor 300 as a paper non-detector is arranged corresponding to the paper feed section and sends a detection signal of "no paper" to the main body of the apparatus. The situation is as follows. Therefore, this large capacity paper feeder 42
The conveyance section 420a of No. 0 has a built-in signal generation control means 428 for controlling the generation of a signal indicating "no paper" even though there is paper P.

As shown in FIGS. 46 and 47, this signal generation control means 428 has a shutter member 429 made of a diffraction plate that can be moved freely with respect to the optical path of the reflective optical sensor 30θ, and has a large-capacity supply. When there is paper P in the paper device 420, the shutter member 429 blocks the light, and when there is no paper P, the light is transmitted through the shutter mechanism.

The shutter member 429 is provided at the free end of an arm 431 that is pivotally supported by a shaft 430, and is in a state where it can open and close an opening 432 formed at the bottom of the conveyance section 420h.

The arm 431 is moved by a spring 433;
/4'4j4, that is, the shutter member 429 is biased to a position where it does not close the opening 432.

Further, a solenoid 34 is provided on the pivot end side of the arm 431.
5 are connected, and by turning on the solenoid 345, the arm 431 is connected to the spring 43.
3, so that the shutter member 429 can be opposed to the opening 432.

In the above embodiment of the fixing device, the upper roller unit 336 can be opened and closed, but as another application example, as shown in FIG. 48, the stepping motor 349 can be driven even when the upper unit 336 is fixed. Then rotate the second screw 348 to remove the first screw 3.
By moving the roller 47 downward, the pressing force between the rollers by the compression spring 342 is released, and an appropriate gap G is formed between the heat roller 338 and the pressure roller 341, thereby allowing jam clearance and service work to be performed. It is also possible.

In addition, in the above embodiment, an example was shown in which the process speed changes only when color copying, but the process speed is also changed when there is an enlargement/reduction mode, a halftone reproduction mode, etc., and two or more modes are used. However, it is also possible to set the roller load accordingly.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist of the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, since the pressure load between the heat roller and the pressure roller is configured to be varied according to the process speed optimal for each mode, variable magnification copying, color copying, Alternatively, it is possible to obtain the optimum fixing conditions for each mode such as the halftone reproduction mode, and it is possible to achieve excellent effects such as being able to reliably prevent the occurrence of paper wrinkles and curls, as well as defective fixing and offset.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of an image forming unit device employing the developer replenishing device of the present invention, FIG. 2 is a schematic longitudinal sectional front view, FIG. 3 is a schematic longitudinal sectional front view of the image forming apparatus, and FIG. 5 is an explanatory diagram of the configuration of the exposure optical device, FIG. 6 is an explanatory diagram showing the cooling air conduction path, and FIG. 7 is a plan view of the operation panel. FIG. 8 is a perspective view showing the operating means of the second optical unit; FIG. 8 is a diagram illustrating the configuration of the main parts; FIG. FIG. 10 is a schematic longitudinal sectional front view of a two-color developing device, FIGS. 11 and 12 are views showing different operating states of the first developing unit, and FIGS. 13 and 14 are views of the second developing unit. Figures 15 and 16 are diagrams showing the operating states of the developing device. Figure 17 is a diagram showing the image forming apparatus with the front cover opened. Figure 18 is the developer replenishing device. 19 is a schematic longitudinal sectional side view showing one embodiment of the developer replenishing device of the present invention, and FIGS. FIG. 21 is a schematic plan view showing the configuration around the developer receiving and transporting section of the second developing unit, and FIG. 22 is a schematic diagram of the developer replenishing device. 23 is a schematic exploded perspective view of the developer replenishing device, FIG. 24 is a schematic front view of the paper feeding device section, and FIG. 25 is a perspective view showing the paper feeding cassette with the cover removed. , Fig. 26 is a perspective view of the cassette cover that also serves as a manual paper feed tray, Fig. 27 is a diagram showing the installation of the guide member of the manual paper feed tray in a supported state, and Fig. 28 is taken along line E in Fig. 27. 29 is a sectional view taken along the Rolo line in FIG. 27; FIG. 30 is a schematic perspective view of a support plate push-up mechanism for pushing up the support plate of the paper feed cassette; FIG. 31 is a schematic configuration explanation of the separation means. Figure, Figure 32 (,
) to (d) are explanatory diagrams showing the paper separation state of the separating means, FIGS. 33(a) and (b) are explanatory diagrams showing the arrangement state of the paper no-paper detector in the paper feed cassette installation part, and FIG. FIG. 35 is a schematic plan view showing the configuration of a roller contact/separation means for approaching and separating the manual feed roller; FIG. 36 is a schematic plan view showing the configuration of the fixing device. A front view, FIG. 37 is a schematic front view of the main part showing the open and closed state of the upper roller unit, which also constitutes the fixing device, FIG. 38 is an explanatory diagram showing the relationship between copy speed and roller load, and FIG. An explanatory diagram showing the relationship between process speed and paper wrinkle occurrence rate. Fig. 40 is a schematic longitudinal sectional front view of the direction changing conveyance device. Fig. 41 is a front view showing the configuration of the paper sorting section of the direction changing conveyance device. , FIG. 42 is a partially cutaway front view showing the configuration of the paper feed section to the temporary stacking section of the direction conversion conveyance device, FIG. 43 is a perspective view of the main part of the paper feed section, and FIG. 44 is the same. FIG. 45 is a schematic longitudinal sectional front view of the image forming unit device in which a large-capacity paper feed device is installed in place of the lowest paper feed cassette, and a stacking device is installed in place of the paper ejection tray. FIG. 46 is a plan view of the signal generation control means incorporated in the conveyance section of the collating device, FIG. 47 is a side view of the signal generation control means, and FIG. 48 is a schematic front view showing another embodiment of the fixing device. It is a diagram. P...Paper, I2...Photoreceptor, 16...Transfer device, 25...Fixing device, 336...Upper roller unit, 337...Lower roller unit, 338...Heat roller, 341... Pressure roller, 342... Compression spring, 343... Bracket, 347... Screw (female type), 348... Screw (male type), 349...
...Stepping motor. Figure 1 Figure 7 Figure 8 Figure 96 Figure 11 Figure 12 Figure 13 Figure 14 Figure 19 Figure 20 (a) (b) Figure 26 Figure 28 Figure 30 Figure 31 Figure 32 (a) (b) Figure 32 (c) lt) 4 Figure 33 28' Figure 34 ζ・ Mocking Q No. 35
Figure 4G Figure 47 Figure 4jl JLJ Figure 48

Claims (2)

[Claims] (1) A fixing device that heats and fixes the developer transferred onto an image support by an image carrier using a heat roller and a pressure roller, wherein the pressure roller is driven by a biasing force of a biasing member. A fixing device characterized in that a pressing force is applied and the length of the urging member is varied via a screw member, so that the pressing force of the pressure roller can be adjusted according to the image forming speed. . (2) The fixing device according to claim 1, wherein the cam mechanism is driven by a stepping motor.