JPH01109361A - Electrostatic printing device - Google Patents

Abstract

PURPOSE:To obtain a printing master of high fixing strength by detecting the surface temperature of a photosensitive body and controlling not only the temperature of the photosensitive body to a value in a set range but also the fixing energy of a flash fixing device in accordance with the detection signal. CONSTITUTION:The copy mode and the print mode are provided; and in the print mode, a photosensitive body 37 is rotated at speed higher than that of the copy mode to perform printing by a master formed on the photosensitive body 37. The master is printed by a flash lamp 52b in a flash fixing device 52 arranged under an exposure and destaticizing lamp 51. The surface temperature of the photosensitive body 37 is detected by a temperature sensor 52d provided before an electrifier 45, and a flash fixing power source 52e is so controlled that the voltage applied to the flash fixing device 52 is raised when the surface temperature of the photosensitive body 37 is low. Thus, the flash fixing device 52 emits light with the quantity of emission light corresponding to the surface temperature of the photosensitive body 37 to fix a toner image formed on the surface of the photosensitive body 37, thereby forming the printing master.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an electrostatic printing device having a copying mode and a printing mode.

[Conventional technology]

Conventionally, after a photoreceptor made of zinc oxide or the like is charged, it is exposed to light in an exposure process to form an electrostatic latent image corresponding to the original, and the resulting electrostatic latent image is made visible in a development process. In an electrostatic printing device that produces a master for printing by fixing the visible image onto a photoreceptor using a flash fixing device, the energy supplied to the fixing device during flash fixing is fixed at a constant level.

For this reason, when the temperature of the photoconductor is low, such as immediately after the printing device is turned on, the amount of heat necessary to fix the visible image on the photoconductor cannot be applied to the toner, and as a result, the amount of heat required to fix the visible image on the photoconductor cannot be applied to the toner. There was a problem with the toner on the printer peeling off.

In order to solve the above problem, it is necessary to set the voltage for charging the capacitor high in advance, for example, in order to increase the energy supplied to the flash fixing device.

[Problem that the invention seeks to solve]

However, when the voltage applied to the flash fuser is increased,
Although fixing performance is improved when the temperature of the photoreceptor is low, it is exposed to strong flash light even when the temperature is high, so-called photo fatigue occurs in which the charging characteristics of the photoreceptor made of zinc oxide etc. are significantly reduced. Since it takes time after that, there are problems such as not being able to obtain good printed matter.

[Means and actions for solving the problem] It has a copy mode and a print mode, and in the print mode, the photoreceptor is rotated at a faster speed than in the copy mode, and printing is performed using a master formed on the photoreceptor. In an electrostatic printing device, a detection means for detecting the surface temperature of the photoreceptor and a heating means for heating the photoreceptor are provided, and heating is performed so that the temperature of the photoreceptor falls within a set range based on the detection signal detected by the detection means. By controlling the fixing device and the fixing energy of the flash fixing device when making masters, we are able to achieve good fixing regardless of the environment or internal temperature of the machine, creating printing masters with high fixing strength. It is an object of the present invention to provide an electrostatic printing device that can obtain the following.

〔Example〕

An embodiment of the present invention will be described in detail with reference to the drawings.

In the figure, reference numeral 1 denotes a main body of an electrostatic printing apparatus, and a platen cover 3 on which a document 2 to be copied or printed is placed is provided on the top. The platen glass 3 is attached to the upper surface of a top cover 4 provided to cover the upper part of the main body 1, and a platen hinged to the top cover 4 side via a hinge 5 is mounted on the platen glass 3. A cover 6 is provided so as to be openable and closable. One end of the top cover 4 is pivotally connected to the main body 1 by a support shaft 7, and the top cover 4 can be opened upward to the other end around the support shaft 7. A light source 8 exposes and scans an original 2 placed on a platen glass 3, and an optical system 9 guides reflected light from the original 2 to a photoreceptor 37, which will be described later.

The light source 8 is, for example, a tubular halogen lamp, which reflects the light emitted from the light source 8 toward the document 2, and is mounted on a carriage 11 together with a flapper 10.
1, the copy surface of the original 2 is exposed and scanned, and the reflected light from the original 2 is reflected by the lens carriage 15 by the first to third mirrors 12.13.1°4 mounted on the carriage 11. It is like being led to the side. The lens carriage 15 is movably supported by a guide rail 16 installed below and parallel to the platen glass 3, and the lens carriage 15 is provided with a lens 17 for condensing light.

Further, a mirror carriage 18 is provided behind the lens 17 and supported by a guide rail 16. The mirror carriage 18 is provided with a fourth mirror 19, which guides the reflected light from the original 2, which is focused by the lens 17, to the photoreceptor 37 side via the dustproof glass 20.

On the other hand, the carriage 11 on which the light source 8 is mounted, the lens carriage 15, and the mirror carriage 18 are driven by a drive system 21 as follows. That is, the drive system 21 has drive sources 22, 23 consisting of two DC servo motors, and these drive sources 22, 23 drive the carriages 11, 15, 18 through power transmission means 24 such as wires. It is designed to drive.

In addition, near the drive gear 26 provided on the drive shaft 25 located above the support shaft 7, when the top cover 4 is opened for paper jams or inspections, the carriages 11
Stopper mechanism 27 to prevent ゜15.18 from falling
is provided. As shown in FIG. 7, the stopper mechanism 27 is a substantially F-shaped plate member 27 fixed to the main body 1 side.
G has a structure in which an elastic body 27b such as a sponge is provided at the tip,
When the top cover 4 is closed, it is spaced apart from the drive gear 26 as shown in FIG. 7, and when the top cover 4 is opened upward about the support shaft 7, the drive gear 26 provided on the top cover 4 side When the top cover 4 is opened, the eighth
As shown in the figure, the top cover 4 is pressed against the elastic body 27b of the stopper mechanism 27 to prevent the drive gear 2B from idling, thereby regulating the movement of the drive system 21.
Even if the carriage is opened, each carriage 11, 15°1
The light source 8, optical system 9, etc. are prevented from being damaged due to the light source 8 falling.

On the other hand, a cooling fan 30 is installed on the pivoting side of the top cover 4. The cooling fan 30 cools the light source 8 during exposure of the original 2, and the cooling air blown by the cooling fan 30 is sent to the light source 8 along the lower surface of the platen glass 3, as shown in FIG. It is now possible to

Above the light source 8, a lamp cover 31 is provided that slopes higher and higher toward the downstream side, and guides the cooling air as a laminar flow to the source between the light source 8 and the platen glass 3. By cooling the light source 8 and the platen glass 3 at the same time, the light source 8 and the platen glass 3 can be effectively cooled with a smaller amount of air.

In this way, the power consumption of the cooling fan 30 is reduced.

Further, the cooling air that has cooled the light source 8 advances along the lower surface of the top cover 4 to the fixing device 160 side, which will be described later.
As shown in FIG. 9 in the after-cooled section 60, the heat is discharged from the main body 1 through the slit 4a formed on the open end side of the top cover 4, and the inside of the main body 1 is heated by the heat emitted from the light source 8 and the fixing device 160. Prevents the temperature from rising.

On the other hand, numeral 35 in the figure is a photoreceptor unit, which is installed on a guide rail 36 installed in the front and back direction inside the main body 1, so that it can be pulled out when replacing the photoreceptor 37 or replenishing developer. .

The photoreceptor unit 35 has a sflow drum 39 which is rotated in forward and reverse directions by a main motor 38 at a speed of, for example, three steps in the forward rotation direction and one step in the reverse direction. There are 4 slits 3 in the axial direction on the outer circumference of the scroll drum 39.
9a is opened, and the photoreceptor 37 housed in the scroll drum 39 is drawn out through this slit 39g. The photoreceptor 37 is a sheet-like material such as paper wound into a roll, and is set on a feeding shaft 4° housed in a scroll drum 39. A master plate 41 is provided in the slit 39a of the scroll drum 39 to prevent toner from entering the scroll drum 39 during rotation. As shown in FIG. 10(B), this master plate 41 has an outer circumferential surface 41a having the same curvature as the scroll drum 39, and the outer circumferential surface 41a is slightly smaller than the outer circumferential surface of the scroll drum 39.
It is installed so that a can be immersed in it. Further, inclined surfaces 41b and 41c having different angles are formed on the inner surface. A notch 41d is provided in the outer circumferential surface 41a that is continuous with the inclined surface 41b located in the normal rotation direction of the scroll drum 39, and when the master plate 41 passes through a developing device 55, which will be described later, the developer is transferred to the scroll drum. 3
9 from entering the inside of the inclined surface 41b.
.

41c is formed at a steep angle, and even if a part of the metal developer enters the scroll drum 39, the developer is discharged to the outside of the scroll drum 39 by falling along this inclined surface 41c. It is now possible to do so.

The rolled photoreceptor 37 is set on the feeding shaft 40.
One end extends out of the scroll drum 39 through a gap between a slit 39a of the scroll drum 39 and a master plate 41 provided to close the slit 39a. The photoreceptor 37 extended outside the scroll drum 39 goes around the outer peripheral surface of the scroll drum 39 almost once, reaches the slit 39a, and forms a narrow gap between the slit 39a and the master plate 41, which are provided on the opposite side of the narrow gap. It is taken into the scroll drum 39 again through the gap and wound around a winding shaft 42 arranged in parallel with the above-mentioned full-out shaft 40.

Note that the winding operation will be described later.

On the other hand, the following parts are installed around the scroll drum 39 along the normal rotation direction of the scroll drum 39.

In the figure, 45 is a charger installed almost above the scroll drum 39, and as shown in FIG.
It has a shield case 45a that is open on the 9 side. Inside the shield case 45a are two rows of partition walls 45b and 45c.
3 chambers in the vertical direction 45. ．． 452,45. The chamber 451 is a static elimination chamber, and the chamber 452.45° is a charging chamber. A static eliminating wire 46 is provided in the static eliminating chamber 451 and stretched between insulating blocks 45d provided at the end of the shield case 45a, so that the photoreceptor 37 can be neutralized by discharging the static eliminating wire 46. It has become. Further, in the charging chambers 452 and 453, a charging wire 4 is stretched in a U-shape between the insulating blocks 45d.
7 are respectively accommodated, and both ends of the charging wire 47 are provided with a first
As shown in Figure 2, a bracket 48 is attached to one end of the plug 48.
It is attached via a.・One end of the plug 48 is screwed to the end plate 45e of the insulating block 45d, and by rotating the other end of the plug 48,
The bracket 48a is movable in the direction in which the charging wire 47 is stretched. As a result, the charging wire 4
After attaching both ends of 7 to the bracket 48a, plug 48
By rotating the charging wire 47, the charging wire 47 can be easily stretched with a predetermined tension.

Also, the gap between the static elimination chamber 451 and the charging chamber 452! 14
5d is a charging chamber 452.45. It is formed higher than the partition wall 45c dividing the space between the static eliminating wire 46 and the charging wire 4.
In addition, an ion control board 49 such as a resin board for controlling the ion flow generated during discharging is installed approximately in the center of the housing 45a (II!!) on the side of the partition wall 45 and the charging chamber 45s. The ion control plate 49 on the side wall side is higher than the opening edge of the side wall, and by restricting the outflow of ions (see the arrow in FIG. 11), the ion control plate 49 is installed on the side wall. Measures are taken to ensure uniform charging.

On the other hand, numeral 50 in the figure is an image area adjustment lamp for erasing unnecessary portions of the electrostatic latent image formed on the surface of the photoreceptor 37 by the exposure operation, that is, the leading edge, trailing edge, and non-image portions on both sides. ing. That is, the lamp case 50a has a slit-shaped opening on the photoreceptor 37 side. As shown in FIG. 13, inside the lamp case 50a, a plurality of lamp chambers 5 are formed by partition walls 50b provided for each size of the document 2.
The lamp chambers 501 to 50n are divided into 01, 502, . The charge on the non-image area on the photoreceptor 37 is erased.

Further, the slit-shaped opening 50d of the lamp case 50a
A light-shielding plate 50e made of a black Mylar plate or the like is installed diagonally along the surface of the photosensitive plate 37 on the lower edge to prevent a part of the light from leaking to the uniform exposure/static charge removal plate 51 side. It is prevented.

The above-mentioned mode light and static elimination lamp 51 is the image area adjustment lamp 5
It is located below 0 and is configured as follows.

In other words, in FIGS. 14 to 16, the photoreceptor 37 side is open.
It has a lamp case 51a as shown in the figure, and the developer etc. enters the inside of the opening 51b and the lamp 51c
A transparent stain prevention plate 51d that prevents stains etc.
is fitted. Furthermore, a large number of lamps 51c are connected in series within the lamp case 51a, and each lamp 51
A group of lamps arranged in two rows so that c is staggered is housed, and in print mode, by uniformly exposing the master image formed on the surface of the photoreceptor, an electrostatic latent image for printing is created. It also has a function of facilitating cleaning by forming the light on the master image and also turning on during cleaning to uniformly expose the surface of the photoreceptor 37.

On the other hand, numeral 52 in the figure is a flash fixing device installed below the above-mentioned exposure/discharge lamp 51, and a flash lamp 52b is housed in a reflector 52a that is open on the side of the photoreceptor 37. This flash lamp 52b blinks in synchronization with the rotation of the photoreceptor 37 in the print mode, and
It has a function of fixing the toner image formed on the photoreceptor 37 by a certain width and creating a printing master on the photoreceptor 37.
Photoconductor temperature sensor 52d installed in front of charger 45
The voltage applied to the flash fixing device 52 from the flash fixing power source 52e is controlled based on the surface temperature of the photoreceptor 37 detected by the flash fixing power source 52e.

That is, the photoreceptor temperature sensor 52d is connected to the printing apparatus main body 1.
When the main body 1 is in operation, it is in a standby position separated from the photoreceptor 37, and when the main body 1 is stopped, the surface temperature of the photoreceptor 37 is detected by coming into contact with the surface of the photoreceptor 37. The detected surface temperature of the photoreceptor 37 is converted into a voltage and then sent to a control circuit. The control circuit determines whether or not the printer main body 1 can be operated based on the input temperature signal, controls on/off of a heater 52f installed near the photoreceptor 37, and applies voltage to the flash fixing device 52 from the flash power source 52e. By performing this control, good master charging performance can be obtained without being affected by the internal temperature of the machine.

Note that the control method will be described later.

Further, in the drawing, reference numeral 55 denotes a developing device installed below the scroll drum 39, which is composed of a developing unit 55b having a housing 55a with an open top, and a toner supply section 56. The developing unit 55b has guide rails 55e installed on both sides of the lower part, and these guide rails 55e are placed on guide rolls 53 provided on the main body 1 side, and the entire developing unit 55b is pulled toward the front side of the main body 1. It's ready to come out. In the opening of the housing 55a, there are two parallel developing rollers 55c near the photoreceptor 37.

55d is provided horizontally. Each of the above developing rolls 55
As shown in FIG. 17, the outer circumferences of the rollers c and 55d are magnetized with five poles on the side of the developing roll 55c and three poles on the side of the developing roll 55d, and are rotated in the same direction as the scroll drum 39 during development so that the outer circumferential surface The magnetic brush formed on the
Photoreceptor 37 wrapped around the outer peripheral surface of the scroll drum 39
It is designed to develop an electrostatic latent image, and below each developing roll 55c, 55d,
A stirring roll 54 is provided to supply the developer to the housing 55d and to stir the developer in the housing 55a. As shown in FIGS. 2 and 18, the stirring roll 54 has a large number of packets 54a provided at equal intervals in the circumferential direction on its outer periphery, and as it rotates, these packets 54a collect the developer at the bottom of the housing 55a. The stirring roll 54 is scooped up and supplied to the developing rolls 55C and 55d, and inside the stirring roll 54 there is a stirring blade 54b inclined at a constant angle with respect to the axis.
A plurality of sheets are provided, and these stirring blades 54b push the stirring roll 54 through the gap 54c between the packets 54a.
The developer that enters the container is stirred to maintain a state in which toner and carrier are always mixed at a constant ratio.

Further, the developer supplied to the developing roll 55d by the stirring roll 54 is scraped off by a spike regulating plate 57 installed near the developing roll 55d.
The spike height of the magnetic plaque formed on the outer peripheral surface of the magnetic plaque is regulated to be constant, and a portion of the developer scraped off by the spike regulating plate 57 is placed below the spike regulating plate 57. The developer flows into the developer concentration detector 58 as shown in FIG. The developer concentration detector 58 has a hopper 58a whose upper surface is open, as shown in FIGS. 20(a) and 20(b).

The width of the hopper 58m becomes narrower as the side plates 58c go downward, and the inclination angle θ of the side plates 58c is 55° to 6.
511, and an opening 58 on the top surface.
The area ratio between d and the opening 58e on the lower surface is set in the range of 12:1 to 7:1, and the length p of one side of the lower opening 58 is 3 m.
It is set to be 1 m or more.

Further, a sensor 58b is provided on the back side of the hopper 58a to detect the toner concentration of the developer passing through the hopper 58a.

By setting the shape of the hopper 58a as described above, the developing rolls 55c and 5
Since there is no difference in density detection even if the speed of developer 5d changes, an image with a constant density can be obtained, and even if foreign matter is mixed into the developer, clogging will not occur in the hopper 58a. Therefore, concentration control will not become impossible.

20(c) and (d) are other examples of the hopper 58a when a developer with poor fluidity is used, and the inclination angle θ is in the range of 55° to 65° as in the above example. I want to be.

- The developer that has completed development on the force photoreceptor 37 is removed by a scraping blade 59 provided in contact with the developing roll 55c.
Developing roll 55. The developer is scraped off from the outer circumferential surface of c, and the scraped developer is removed by the scraping blade 59
A cross mixer 60 provided below mixes the mixture as follows.

That is, in the cross mixer 60, as shown in FIGS. 21 and 22, box-shaped passages 60b and 60'c are formed on both sides of the scraping blade 59, which are partitioned by side plates 60a. The developer that falls from above the passages 80b and 80c is placed in the passages 60b and 60c in the 22nd passage.
As shown in the figure, a plurality of guide plates 60d and 60e are provided diagonally to change the flow to the left and right, as shown by solid line arrows and dotted line arrows (the dotted line arrows indicate the flow on the back side).
The developer that is guided by these guide plates 60d and 80e and falls from below the cloth mixer 60 is mixed using a falling blade. An auger 61 is provided for mixing the supplied toner and the developer dropped from the cross mixer 60 with the developer in the housing 55a. As shown in FIG. 23, the auger 61 is provided with fins 61m spirally wound in the left-right direction from approximately the center in the opposite direction. By conveying the developer toward the outside of the housing 55m as it rotates, the agitation performance of the developer is improved and the developer can be mixed efficiently.

On the other hand, the toner supply section 56 has a toner housing 56a whose bottom portion is pivotally attached to the side of the developing unit 55b by a bottle 65. The upper part of the toner housing 56a is a semi-cylindrical cartridge guide 56b, and a cylindrical toner cartridge 62 can be inserted and removed from the end side of this cartridge guide 56b. The toner cartridge 62 has toner stored therein, and a seal (
(not shown) is removed, the cartridge guide 56b is inserted from one end side with the opening facing upward, and after insertion, the toner cartridge 62 is rotated approximately 180'' to remove the toner stored in the toner cartridge 62. It is designed to be dropped into the housing 56a for replenishment.

Further, an agitator 63 is provided below the cartridge guide 56b, and a supply roll 64 is provided in the lower opening 56d of the toner housing 56a. The agitator 63 is formed of a wire as shown in FIG. 26, and rotates clockwise at a speed of about 7.3 rpm to prevent the toner supplied from the toner cartridge 62 from causing a blocking phenomenon. The mixture is stirred so as to reach the supply roll 64.

A wiping body 66 made of a thin Mylar plate is attached to one end of the agitator 63 by a clip 67'. This wiping body 66 rotates together with the agitator 63 and wipes off the toner adhering to the detection surface of the toner detector B7 provided at the bottom of the toner housing 56a.
The presence or absence of toner in 6a can be reliably detected.

On the other hand, the supply roll 64 provided at the lower opening 56d of the toner housing 56a is entirely made of a foam such as polyurethane resin, and a portion of the toner enters into a large number of holes provided on the surface. ing. Furthermore, a protrusion 56e provided at the edge of the opening 56d and having a substantially semicircular cross section is bitten into the outer circumference of the supply roll 64, and the toner that has entered the hole in the outer circumference as the supply roll 64 rotates is absorbed. The liquid is squeezed out and supplied to the housing 55a of the developing device 55 through the rotation 56d. As a result, 0.5 g of toner can be supplied into the housing 55a per second at a rotation speed of 4 rps, and the supply capacity may decrease or the supply roll 64 may wear out during long-term use. In this case, the supply roll 64 can be easily cleaned or replaced by rotating the toner housing 55a about the pin 65 to the position shown by the imaginary line in FIG.

On the other hand, it has already been explained that the developing unit 55b of the developing device 55 can be pulled out toward the front side of the main body 1 along the guide rail. development unit 55b
must be fixed in a constant position at all times.

The next positioning pin 70 does this. A total of four positioning pins 70 are installed, two at the rear of the main body 1 and two at the front. Each positioning pin 70 is the 29th
As shown in the figure, the bracket 1a has a conical tip facing the direction in which the developing unit 55b is extracted, and its base end is on the main body 1 side.
is fixed to. Further, a bottle hole 55h is opened on the front and rear bracket 55g side of the developing unit 55b at a position where the positioning pin 70 can be inserted.
5b, the pin holes 55 of these brackets 55g
h is fitted into the positioning pin 70, thereby positioning the developing unit 55b, and at the same time, the latch means 71 locks the developing unit 55b and prevents it from being pulled out.

Note that when the developing unit 55b is positioned by the positioning pin 70, the developing unit 55b is held floating above the guide rail 36.

Further, in the developing device 55, the developer can be replaced as follows.

FIG. 30 shows the developer replenishment unit 75, which has a semi-cylindrical cartridge accommodating portion 75a with an open upper surface.
have. A drop lower 5b is opened at the bottom of the cartridge accommodating section 75a, and a skirt section 75c is formed at the bottom of the supply unit 75.
Both ends of this skirt portion 75c can be placed on a guide rail 36 that guides the insertion and removal of the photoreceptor unit 35. In addition, a handle 75d is provided on the side of the supply unit 75 for easy handling, and a handle 75d is provided on the side of the supply unit 75 to facilitate handling.
A chute 75e is provided below the drop lower 5b to guide the developer falling from the drop lower 5b toward the developing roll 55c. To replace the developer, first open the front cover (not shown) of the main body 1 and take out the photoreceptor unit 35 toward the front, then insert the skirt portion 75c of the developer replenishment unit 75 into the photoreceptor unit. 35 is placed on a guide rail 36 that guides the insertion and removal, and is pushed into a predetermined position along the guide rail 36. At this time, the cartridge accommodating portion 75a of the replenishment unit 75
To do this, load the opened developer cartridge 76 in advance, then close the front cover of the main body 1 and press the developer exchange switch 77 provided on the outer surface of the main body 1. The developer cartridge 76 is rotated approximately 1806 times, and the developer cartridge 76
The developer inside the housing 55 is guided from the drop lower 5b to the reshoot 75e and falls onto the developing roll 55d.
It is replenished into a.

Furthermore, when replacing the developer in the housing 55a, the empty developer cartridge 76 is replaced with the developer unit 55b.
With the developer set in advance on the catch pan 78 shown in FIG. 27 installed below, open the developer discharge gate 55f shown in FIG. Press the developer exchange switch '77 provided on the side. As a result, the developing roll 55c,
55d and the stirring roll 56 rotate, and the housing 55a
The developer inside is discharged from the developer discharge gate 55f into the developer cartridge 76 on the catch pan 78, and when replenishing new developer, the above-mentioned replenishment operation may be performed.

However, if you forget to set the empty developer cartridge 76 onto the catch pan 8 when replacing the developer and open the developer discharge gate 55f, the developer will scatter onto the catch pan 78 and stain the inside of the machine. There is a risk.

Therefore, a detector 190 such as a limit switch is provided at the back of the catch pan 78, as shown in FIG. When the empty cartridge 76 is not detected, the developing rolls 55c and 55d and the stirring roll 56 do not rotate even if the developer exchange switch 77 is pressed. As a result, even if the developer discharge gate 55f is opened and the developer exchange switch 77 is pressed without setting the empty cartridge 76 on the catch pants 8, the developer will not be discharged, so that the interior of the machine can be prevented from becoming dirty. At the same time, if the developer exchange switch 77 is pressed without setting the empty cartridge 7B, the display 1811 on the operation panel 180: "Please set a cartridge" will be displayed, and if the empty cartridge 76 is not set. When it is time to set, a message ``replacing'' is displayed.

On the other hand, when replacing the developer, since the developing rolls 55c and 55d are rotated while the photoreceptor 37 is stopped, a part of the photoreceptor 37 in contact with the developing rolls 55c and 55d is stained in a band shape, and the developer is replaced. When a subsequent copy is made, black band-like stains or fog appear on the first copy.

Furthermore, in the print mode, black band-like stains occur on the master, causing a problem in which stains occur on all printed matter.

Therefore, in this embodiment, after the developer replacement is completed, the main body
When the front door of the photoreceptor 37 is closed, an interlock switch is activated, and a cleaning operation of the photoreceptor 37 is automatically performed in response to a signal from the interlock switch.

That is, when the front door is closed, the static elimination lamp 51 is turned on in response to a signal from the interlock switch that is activated, and the static electricity on the photoconductor 37 is eliminated.
The developer on the surface is the developer roll 5"5c which also serves as a cleaning brush.

It is removed by a magnetic brush 55d.

When the photoreceptor 37 rotates once and the cleaning of the photoreceptor 37 is completed, the main motor is stopped and the message "Ready to copy" is displayed on the display section 181 on the operation panel 180.

As a result, band-shaped stains formed on the surface of the photoreceptor 37 at the time of developer replacement are automatically removed by the cleaning process, so that a stain-free image can be obtained from the first copy.

As the leaning method, a blade cleaning method using a cleaning blade may be adopted.

On the other hand, reference numeral 80 in the figure indicates a paper feeding device, which includes paper cassettes 81 in multiple stages, for example, two stages. These paper cassettes 81 can be freely pulled out toward the front side of the main body 1 along guide rails 82, and a cassette holder is detachably mounted in a stand 83.

The cassette holder has two cassette fixing bins 83a projecting from the bottom of the stand 83 as shown in FIG. 81 is positioned and fixed.

The cassette holder has paper 8 at the bottom of the base 83 on the paper feed side.
A tong 87 is provided, the proximal end of which is fixed to a rotating shaft 86 provided in a direction perpendicular to the paper feeding direction of No. 5, and the distal end of which is vertically rotatable about the rotating shaft 86. At one end of the rotation shaft 86, a cassette holder is provided protruding toward the back of the stand 83, and one end of a lever 86a is fixed to the tip. One end of a tension spring 88 is locked to the other end of the lever 86a, and the other end of the tension spring 88 is the tip of a rotating lever 89 whose proximal end is pivoted to the bottom of the base 83. It is locked to. The rotating lever 89 is such that when the cassette holder base 83 is pushed into the main body 1 along the guide rail 82, the tip comes into contact with a wedge-shaped cam 90 provided on the main body 1 side. As a result, the rotation lever 89
The tip of the tension spring 88 is rotated in the tensioning direction of the tension spring 88. When the tension spring 88 is tensioned, the rotation shaft 86 is rotated by the tension via the lever 86a, which causes the tip of the tongs 87 to rotate upward and push up the bottom of the paper cassette 81. The paper 85 accommodated therein is brought into pressure contact with a feed roll 91 provided on the paper feeding side from below.

Furthermore, the cassette holder pushed into the main body 1 is placed on a stopper 92 provided on the main body 1 side, and the cassette holder is placed on the pedestal 83.
By locking the stud bin 93 provided on the side, the base 83 of the cassette holder is fixed to the main body 1, and at the same time, the protrusion 81a for detecting the paper size provided on the paper cassette 81 side detects the paper size. It acts on the size detection switch 94, whereby the size of the paper 85 set in the paper cassette 81 is detected.

Further, the drive system of the paper feeder 80 and the conveyance of the paper 85 are as follows. When you push the cassette holder stand 83 into the main body 1,
For the cassette holder, the joint 95a on the stand 83 side is the joint 9 on the main body 1 side.
5b, and the clutch 97 is connected to the drive system 96 of the main body 1.
and is transmitted to the drive shaft 97 of the feed roll 91 via joints 95b and 95a. The drive shaft 97 includes
A support member 91a of the feed roll 91 is supported so as to be movable in the axial direction. The support member 91a has a 36th
As shown in FIG. 37, a feed roll 91 is rotatably supported, and the power transmitted to the drive shaft 97 is transmitted to the feed roll 91 via a gear 98 and a one-way clutch 99, and the feed roll 91 is rotatably supported. roll 91
is rotated, and the sliding member 1 is attached to the drive shaft 97.
00 is attached so as to be freely movable in the axial direction. A paper scraping member 100b having a claw body 100a is attached to the sliding member 100, and is configured to fit into a square hole (not shown) provided in the support member 91a of the feed roll 91, thereby allowing the support The vertical movement of the member 91a is regulated, and it is linked to the guide 81b provided with the protrusion 81a for detecting the paper size, and when the guide 81b is moved according to the paper size, the supporting member of the feed roll 91 is moved. 91a is also moved so that even if the size of the paper 85 changes, the paper is fed at a constant position from the edge of the paper.

Also, the feed roll 91 has a one-way clutch 9.
9 is incorporated, and when the transport roll 113 (to be described later) starts transporting the paper 85, the one-way clutch 99 causes the feed roll 91 to idle, thereby reducing the resistance during paper transport. The support side end of the support member 91a that supports the support member 91a is formed in an arc shape, and between this arc-shaped portion 91b and the paper guide plate 112, the paper 85 carried out by the feed roll 91 is prevented from becoming skinny. It has become.

On the other hand, the cassette holder is connected to the drive shaft 1 provided on the rear end side of the stand 83.
01 is the cassette lifting motor 10 via the joint 101a.
2, and the paper cassette 81 is raised by this motor 102 via a cable 103 while maintaining a horizontal state. The cassette receiver is provided with a screw 104 whose height can be adjusted freely at the bottom of the stand 83, and this screw 104 is attached to an actuator support 105 (see FIG.
By turning off the microswitch 106 attached to the cassette holder (see b), the raising of the cassette tray 83 is stopped, and this position becomes the paper 85 conveyance and feeding position. Reference numeral 107 in the figure is a stopper bin that prevents the set paper 85 from shifting by inserting it into a square hole (not shown) provided for each paper size. Further, 108 indicates a detector for detecting the presence or absence of the paper 85 in the paper cassette 81, and 109 indicates a detector for detecting whether the paper 85 is set for horizontal feeding or vertical feeding.

On the other hand, a paper transport mechanism 110 is provided between the feed roll 91 and the photoreceptor unit 35. As shown in FIG. 38, the paper transport mechanism 110 includes a paper guide plate 111 that guides the paper 85 fed from the upper paper cassette 81, and a paper guide plate 111 that guides the paper 85 fed from the lower paper cassette 81. It has a paper guide plate 112, and a conveyor roll 113 is provided at the junction of these guide plates 111, 112.

The conveyance roll 113 is biased upward at a plurality of locations on the rotating shaft 113a by a biasing means 121 such as a leaf spring, and is uniformly pressed against a pinch roll 114 provided above. The pinch roll 114 is rotatably supported at both ends of a rotating shaft 114a near a bent portion of a support link 115 having a substantially reverse C-shape. One end of the support link 115 is pivotally connected to an upper guide plate 116 provided behind the transport roll 113 via a pin 117, and the other end of the support link 115 is pivotally connected to the lower end of the link 118. ing.

A paper guide plate 111 is also connected to the lower end of the link 118 via a small link 119.
8 is connected to a vacuum suction conveying means 145, which will be described later. When the vacuum suction means 145 is opened upward, the pinch roll 114 and paper guide plate 1 are moved around the bin 117.
11 has risen and the paper 85 has jammed on the conveyance path.
It is now possible to remove etc.

Further, a vertical guide plate 121 is provided behind the conveyance roll 113.
．． 122 forms a conveyance path 123.

The conveyance path 123 is connected to the opened sheet 85 until the registration sealant roll 124 provided on the downstream side starts rotating.
Approximately triangular spaces are formed in the upper and lower guide plates 121 and 122 so that the paper 85 can be placed in a loop, and an auxiliary guide plate 125 is formed from the lower guide plate 122.
is installed protrudingly. The auxiliary guide plate 125 creates a trigger for forming a loop in the paper 85, and has a hollow mountain shape, one end of which is pivotally attached to the conveyance roll 113 side, and is conveyed by a biasing means 126 such as a spring. It is biased to protrude into channel 123 (see Figure 40). If the paper 85 being conveyed is thick, the waist of the paper 85 causes it to sink downward as shown in FIG. 41, forming a large loop in the paper 85.

On the other hand, in the registration 124 provided downstream of the conveyance path 123, the shaft portion 124 is biased by biasing means 127 such as a plurality of leaf springs, as shown in FIG. The paper 85 is rotated in response to a paper feed signal, and conveyed sequentially from the leading edge of the paper 85 to the photoconductor 37 side, and one side of the paper 85 fed to the photoconductor 37 side is It rides on a peeling belt 131 provided on a peeling means 130, as shown in FIG.

The peeling belt 131 is formed of a thin metal plate such as stainless steel, and the upper end side has a bracket 13 attached to the main body 1 side.
It is fixed by 2. Further, the middle part of the peeling belt 131 is curved along the outer circumferential surface of the photoreceptor 37, and a tongue piece 131a is cut and raised slightly above the middle part to curve in the opposite direction to the above-mentioned curve. Tongue piece 131
The leading edge of the paper 85 that has reached point a is guided by the tongue piece 131a and is sequentially peeled off from the surface of the photoreceptor 37.

The peeling belt 131 is separated from the photoreceptor 37 in the same way as the photoreceptor 31 is taken in and out.

That is, the lower end side of the peeling belt 131 is engaged with a guide member 135 having a bracket portion 135a pivotally supported by a pin 136, as shown in FIG. The guide member 135 is normally biased to a position where it guides the leading edge of the paper 85 between the photoreceptor 37 and the transfer device 140 by a biasing means 137 such as a tension spring.
1 is pressed against the photoreceptor 37 by a biasing means 137. Further, below the guide member 135, as shown in FIG.
A cam 139a is attached to the tip of this arm 139. When the photoreceptor unit 31 is pulled out, this cam 139a rides on a cam follower 36a provided on the guide rail 36, thereby causing the arm 139 to move. 139 rotates upward and pushes up the guide member 135, the peeling belt 131 whose lower end is engaged with the guide member 135 is separated from the photoreceptor 37 and the photoreceptor unit 3
1, the peeling belt 131 prevents the photoreceptor 37 from being damaged.

On the other hand, in the transfer device 140, as shown in FIG. 48, insulating blocks 140b are provided at both ends of a shield case 140a which is open on the photoreceptor 37 side, and two corotron wires 140c are inserted between these insulating blocks 140b. is installed. A guide 140d prevents the leading edge of the paper 85 from entering the opening of the shield case 140a.
are provided diagonally for each paper size, and a planar adsorption tape 141 is attached to the side surface of the shield case 140a, and the planar adsorption tape 141 allows the sheet to be easily attached and removed at a predetermined position. ing.

Further, the paper 85 that has been transferred by the transfer device 140 is peeled off from the photoreceptor 37 by the peeling belt 131, and then conveyed to the fixing device 160 by the vacuum suction conveyance means 145.

As shown in FIG. 43, the vacuum suction conveying means 145 has a drive shaft 146 supported by the frame 1b on the main body 1 side, and a drive system 147 connects a power transmission shaft 148 and a turn roll 149 to the drive shaft 146. Power is transmitted through the A plurality of rolls 146a are provided at intervals on the drive shaft 146, and an endless conveyor belt 151 is placed between these rolls 146a and a roll 150a of a roll shaft 150 provided parallel to the drive shaft 146. is wound on each roll 146a, 150a. Further, above the turn roll 149, a turn belt 151a is provided. The turn belt 151a is wound between three pulleys 153 arranged at each vertex of a triangle, and is wound around an arm 152.
The peeling belt 13 is pressed against the outer peripheral surface of the turn roll 149 by the action of a torsion spring 154 that biases the peeling belt 13.
The leading edge of the paper 85 separated by 1 is transferred to the conveyor belt 151.
One of the pulleys 153 is supported by an arm 152, and when a paper jam occurs, this pulley 153 is swung together with the arm 152 to loosen the turn belt 151a, thereby removing the paper jam. The paper 85 that caused the problem can be easily removed. Further, the tip of the arm 152 is locked to a locking piece 155a cut and bent on the bracket 155,
It positions a pulley 153 provided at 52.

On the other hand, a groove 149a is provided in the turn roll 149 as shown in FIG. 43, and a pin 146b provided on the drive shaft 146 side is fitted into this groove 1498. By transmitting power from the power transmission shaft 148 side to the drive shaft 146, there is no need to provide a separate joint.
This makes installation easier.

Further, a suction duct 155 is installed below the conveying surface of the conveying belt 151. The upper surface of the suction duct 155 has a large number of suction holes 155a between the conveyor belt 151.
are opened, and these suction holes 155a allow the paper 8
5, the paper 85 is transferred to the conveyor belt 151.
In addition to being pressed upward, the suction holes 155a are opened more on the inside than on the outside and on the side of the fixing device 160 to improve conveying force and prevent the leading edge of the paper from curling on the side of the fixing device 160. At the same time, the suction hole 15
5a itself has a conical shape to improve suction power.

The vacuum suction conveying means 145 can rotate upwardly around a drive shaft 146, and at this time, the paper guide plate 111 and the like connected via the link 118 are simultaneously opened upwardly, and the vacuum Adsorption conveyance means 145
As shown in FIG. 51, the plate stay 156 provided between the main body 1 and the main body 1 is held in the open position.

On the other hand, the fixing device 160 includes a fixing roll 161 having a built-in heat source 163, and a sheet 85 to be fixed on the fixing roll 161.
and a pressure roll 182 that presses the. On the entrance side of these rolls 161 and 162, a carry-in chute 184 that guides the paper 85 is provided at an angle so as to become higher in sequence.A release agent is applied to the surface of the fixing roll 161 above the carry-in chute 164. A metering blade 165 is provided.

Further, behind the fixing roll 161, a paper peeling mechanism 170 for peeling the paper 85 from the fixing roll 161 is provided. As shown in FIG.
have. The peeling claw 171 is attached below a support of a carry-out chute 173 that is rotatable upward about a support shaft 172. The paper peeling claw 171 has a shaft 173a.
One end side of a pair of links 174 is connected by a pin 175, and the link 17
The other end of 4 is connected to the carry-out chute 173 side, and when the carry-out chute 173 is opened from the paper peeling position to the position shown by the imaginary line in FIG.
The tip of the paper peeling claw 171 is positioned opposite to the shaft 173a, so that the user is not injured by the tip of the paper peeling claw 171.

The paper 85 peeled off from the fixing roll 161 by the paper peeling claw 171 is transferred to the paper output tray 1 by the carry-out roll 175.
76. As shown in FIG. 56, the discharge roll 175 is composed of a relatively wide drive roll 175a and a narrower pinch roll 175b, and between each pinch roll 175b and the central drive roll 175a. roll 175C, which has a slightly larger diameter than these.
is provided, and by curving the paper 85 in a waveform, the paper 85 has stiffness, and the paper 85 can be conveyed smoothly.

Further, as shown in FIGS. 57 and 58, the paper ejection tray 176 has a bottom plate 176a that is inclined so as to be gradually raised toward the paper 85 delivery side, and a plurality of air vent holes 176e are formed in both side plates 176b. It is wide open,
By removing the air between the sheets 85 that are continuously discharged through these air vent holes 176C, the falling speed of the sheets 85 can be increased to cope with higher speeds.

Next, as shown in Fig. 61, the control system and Figs.
The operation will be explained with reference to the timing chart shown in FIG.

The operation of the electrostatic printing apparatus configured as described above consists of two steps: warming up before the start of copying, copying operation, and printing cycle.

When you turn on the power switch of the copying machine main body 1 to start copying, the display section 181 provided on the operation panel 180 will show "
The message "Omachi Kudasai" is displayed and the system enters the warming-up operation. At this time, the fixing roll 16 of the fixing device 160
When the heat source 163 provided in the fixing roll 1 is energized, the fixing roll 1
At the same time, the surface of the fixing roll 161 is heated, and a pressure roll 162 provided below the fixing roll 161 is pressed against the fixing roll 161 by a cam means (not shown), and in this state, both rolls 161 and 162 are rotated to reach the set temperature. The temperature is raised to .

When a temperature detector (not shown) installed near the fixing roll 161 detects that the surface temperature of the fixing roll 161 has reached a set value, it stops energizing the heat source 163 and simultaneously outputs a warming-up completion signal. Then, “copy available” is displayed on the display unit 181.

Next, a normal copying operation will be described. The original 2 to be copied is placed on the platen glass 3 provided at the top of the main body 1, the platen cover 6 is closed, and the copy start button 183 is pressed in this state.

As a result, the optical system provided below the platen glass 3 starts exposure scanning of the original 2. The reflected light from the original 2 passes through the first to third mirrors 12. lit.

14. The light is guided by the condensing lens 17, the fourth mirror 19, etc., and is focused on the photoreceptor 37 wrapped around the circumferential surface of the scroll drum 39, and an electrostatic latent image is formed on the photoreceptor 37. Ru. This electrostatic latent image is developed into a toner image by a developing roll 55C155d provided in the developing device 55,
The charger 140 is reached.

On the other hand, the copying machine main body 1 is provided with two paper trays 81, the upper paper tray 81 can accommodate 250 sheets of paper, and the lower paper tray 81 can accommodate 1000 sheets of paper 85. The size of the paper 85 accommodated in each tray 81 is determined by a paper size detection switch 94.
are detected and displayed on the operation panel 180.

Furthermore, by selecting the number of copies and the reduction ratio in advance before copying, the paper 85 corresponding to the original size and reduction ratio is transferred from the paper tray 81 to the transfer device 14 by the paper transport mechanism 110.
It is sent towards 0.

A registration silane roll 12 is placed in front of the transfer device 140.
4, rotation is started in synchronization with the rotation of the photoreceptor 37, and the paper 85 is transferred to the photoreceptor 37 by the transfer device 140 in a state where the toner image on the photoreceptor 37 and the paper 85 are aligned.
The toner image on the photoreceptor 37 is transferred to the paper 85. Further, a part of the paper 85 that has reached the photoconductor 37 is removed by a peeling belt 1 provided so as to be in contact with the circumferential surface of the photoconductor 37.
31, when the leading edge of the paper 85 reaches the tongue piece 131a provided on the peeling belt 131, it is curved in the direction away from the photoreceptor 37 along the tongue piece 131a, and the paper 85 is bent away from the photoreceptor 37 from one end side. The paper 85 is peeled off.

The leading edge of the paper 85 that has been peeled off from the photoreceptor 37 enters between the turn roll 149 and the turn belt 151 that is pressed against the turn roll 149 and the turn belt 15.
1, the paper 85 is actively separated from the photoreceptor 37 while being sent to the vacuum suction conveyance means 145 side.

On the other hand, the paper 85 that has reached the vacuum suction conveyance means 145 is pressed against the conveyor belt 151 by the suction action of the suction duct 155, and the rotation of the conveyor belt 151 causes the fixing device 1
60.

During the warming-up operation of the fixing device 160, the fixing roll 161 is heated to a temperature that allows fixing, and the paper 8
5, the fixing roll 161 and the pressure roll 16
2, the toner image transferred onto the paper 85 is fixed.

The sheet 85 on which fixing has been completed is peeled off from the fixing roll 161 by a peeling claw 171 of a paper peeling mechanism 170, and then discharged to a paper discharge tray 176 by a discharge roll 175.

The above-mentioned copying operation is repeated for a preset number of copies, and the speed during the above-mentioned copying operation is Pv. Also, during the copying operation, the cooling fan 30 rotates and continues to send cooling air along the lower surface of the platen glass 3, cooling the light source 8, the fixing device 160, and the paper 85 that has just been fixed. is discharged to the outside of the main body 1 through the slit 4a.

The above is a normal copying operation, but next, a printing operation will be explained. When a print mode is selected with a button on the operation panel 180, the print mode is entered. The print mode includes a plate making process (speed pv,) for creating a print master and a printing process (speed pv3) for printing using the print master.

First, the document 2 to be printed is set at a predetermined position on the platen glass 3, and the reduction ratio and the number of copies to be printed are set. In addition, since the number of sheets of paper 85 used for printing increases, the paper 85 to be used is stored in the lower paper tray 85, which has a larger storage capacity.
, and select the lower tray 81 using the tray selection button.

On the other hand, there are two print modes: automatic print mode and manual print mode. When automatic print mode is selected, the plate making process and printing process to create a print master are all performed automatically, and when manual print mode is selected, these processes are performed separately. It can be carried out.

If you now select automatic print mode or manual print mode and press the start button to start printing, the platen glass 3
The exposure point scanning of the original 2 above is performed in the same way as when copying,
An electrostatic latent image is formed on the photoreceptor 37 on the scroll drum 39. The non-image area of this electrostatic latent image is erased by an image area adjustment lamp 50 that is turned on according to the document size, and reaches the developing device 55.
c and 55d, an electrostatic latent image is formed on the original.

On the other hand, during the plate-making process, the paper transport mechanism 110 and the transfer device 14
Since 0 is at rest, the developed toner image is on paper 85.
The leading edge reaches the developing device 55 again without being transferred.

If the manual printing mode is selected in advance, the plate can be corrected at this stage. When correcting the plate, after selecting the manual printing step button for "plate making/correction", pull out the photoreceptor unit 35 from inside the main body 1 and delete unnecessary portions of the toner image formed on the photoreceptor 37. After the correction is completed, the plate is set in the predetermined position again by mounting the photoreceptor unit 35, and the plate-making process is started.
If you make a mistake when correcting the plate, if you move on to the plate-making process, an unusable plate will be made, and the cost of clothing and the time required to make the plate will be wasted.

Therefore, in this embodiment, if a mistake is made when correcting the version,
When the all clear key on the operation panel 180 is pressed, a cleaning process is automatically carried out, and all unfixed toner images on the photoreceptor 37 are cleaned.

That is, the steps from step ■ to step ■ shown in Fig. 68 are the steps in the print mode, but during plate production and correction from step ■ to step ■, a correction error is made and the all clear key is pressed at step ■. Then, after the static eliminating corotron and the static eliminating lamp are turned on and the unfixed toner image on the photoreceptor 37 is neutralized, the developing roll 55c is moved in step (2).

55d performs magnetic brush cleaning to remove all unfixed toner images, so if plate making is to be performed again, steps 1 and 2 in FIG. 68 can be repeated.

If you press the All Clear key to return to the copy cycle, the display 181 of the operation panel 180 will display "Copy ready".
is displayed, and if the all clear key is pressed when the master has already been made, the display section 181 will display the message ``Ready to print''.

On the other hand, the above plate correction is performed by pulling out the photoreceptor 37 together with the photoreceptor unit 35 out of the main body 1. At this time, the magnetic brushes formed around the developing rolls 55c and 55d are in contact with the circumferential surface of the photoreceptor 37. Therefore, if the photoreceptor 37 is pulled out in this state, the unfixed toner image on the photoreceptor 37 will be disturbed by the magnetic brush, and a black band-like unnecessary image will be generated on the photoreceptor 37.

Therefore, in order to prevent these problems, when the plate correction mode is selected on the operation panel 180, the tip of the magnetic brush is cut off after the plate correction process shown in step (2) in FIG. 88.

A developing roll 55c is used as a method for cutting off the panicle.

55d is rotated in a direction opposite to that during development, and 55d is rotated in a direction opposite to that during development (in the direction of the broken line arrow in FIG. 24), and the stirring roll 54 is stopped.

As a result, the developer around the developing rolls 55c and 55d flows backward and falls into the housing 55a, so that the magnetic brushes formed around the developing rolls 55c and 55d can be cut off, and this state photoreceptor 37
By pulling out the magnetic brush, it is possible to prevent the unfixed toner image from being disturbed by the magnetic brush and from forming a black band-like unnecessary image on the photoreceptor 37.

Note that it is preferable to always perform the cutting off of the magnetic brush by rotating the developing motor in reverse for a certain period of time when the developing motor is stopped, thereby causing the photoreceptor 37 to rotate idly and moving the unfixed toner image to the fixing position. Also, it becomes possible to prevent the unfixed toner image from being disturbed by the magnetic brush.

In addition, the developing rolls 55c and 5 are cut from the photosensitive member 37.
5d may be spaced apart.

On the other hand, the toner image formed on the photoreceptor 37 is fixed by a flash fixing device 52. The flash fixing device 52
In order to prevent danger due to high-voltage strong discharge, the fixing start signal and the flash trigger are connected to the lamp 51c based on the logical sum of the signals.
A control method is adopted in which the light is emitted.

In addition, during flash fixing, the surface temperature of the photoreceptor 37 is first taken into the control circuit 52e by the photoreceptor temperature sensor 52d, but at this time, if the photoreceptor temperature is, for example, 5° C. or lower, as shown in FIG. 69 (a). The process proceeds from step (2) to step (2) to prohibit the operation of the main body 1 of the apparatus, and also proceeds to step (2) to turn on the heater 52f to heat the vicinity of the photoreceptor 37.

Thereafter, when the photoreceptor temperature becomes 5° C. or more, the process proceeds to step (2) to determine whether the photoreceptor temperature is 10° C. or more, and if it is less than 10° C., the heater 52f is subsequently turned on in step (2).

When the temperature of the photoreceptor 37 reaches 5° C. or more, the process proceeds to step (2), where the applied voltage is calculated from the temperature signal from the photoreceptor temperature sensor 52d, and the flash fixing power source 52g is controlled at step (2).

That is, when the surface temperature of the photoconductor 37 is low, the flash fixing power source 52g is controlled so that the voltage applied to the flash fixing device 52 is high, and when the surface temperature is high, the applied piezoelectricity is controlled to be low.

As a result, the flash fixing device 52 emits light with an amount of light corresponding to the surface temperature of the photoreceptor 37, and the toner image formed on the surface of the photoreceptor 37 is fixed, thereby forming a master for printing.

FIG. 69(C) shows the relationship between the master (photoreceptor) surface temperature and the intensity of the fixed toner image (master fixing strength), and FIG. 69(D) shows the relationship between the applied voltage of the flash fixing device 52 and the master fixing strength. Shows the strength relationship. FIG. 69(e) shows the relationship between the master surface temperature and the applied voltage of the flash fixing device 52. As shown in this figure, when the master temperature is low, the applied voltage is increased, and as the master temperature rises, the applied piezoelectricity is lowered in steps. Master fixing strength can be increased without increasing optical fatigue.

On the other hand, at the time when the toner image is fixed on the photoreceptor 37 by flash exposure by the flash fixing device 52, the charged potential of the photoreceptor 37 has decreased to around 0. Therefore, in order to restore the original potential, recovery control is performed using the following two methods.

Firstly, the charger 45 and the transfer device 145 having the same polarity as the charger 45, for example, are simultaneously turned on to charge the photoreceptor 37, thereby recovering the charge potential drop caused by optical fatigue. Voltages of the same polarity are applied to the device 45 and the transfer device 145 to cause the photoreceptor 37 to rotate idly. According to this method, fatigue recovery can be accomplished in 3 to 4 times of idling, compared to the conventional case in which recovery was performed by lighting the uniform exposure/discharge lamp 51.

Further, if a voltage of the same polarity as that of the charger 45 is applied to a peeling corotron, a neutralizing corotron, or the like having a polarity opposite to that of the charger 45 to perform charging, the photoreceptor 37 can recover from fatigue in a shorter time.

On the other hand, the second method is to perform a recovery operation prior to the flash fixing operation, and to explain this next, the charging characteristics of the photoreceptor 37 are closely related to the amount of attached oxygen.
- It is known that a photoreceptor 37 that has been charged and exposed several times has better recovery properties than a photoreceptor 37 that has not been used.

However, in the case where the photoreceptor 37 is rolled up and used as in the present invention, a master is often created using the photoreceptor 37 which is not subjected to any charging exposure.

In such a case, the fatigue recovery property of the photoreceptor 37 decreases.

Therefore, in the second method described above, the charger 4 at the time of flash fixing
5 to charge the surface of the photoreceptor 37 prior to flash fixing (see FIG. 63).

The rotation of the photoreceptor 37 during flash fixing is at the plate making speed Pv2.
Since it is slow at the same time, the recovery operation that sufficiently attaches oxygen is performed before reaching the flash fixing device 52, and flash fixing is performed.

Further, even after the toner image is fixed on the photoreceptor 37 by flash fixing and a master is created, voltage is applied to the charger 45 again and the charger 45 performs a recovery operation.

As a result, even after flash fixing, the photoreceptor 37 can be restored to the same chargeability as before flash fixing.

In the above description, the recovery operation is performed prior to flash fixing, but the recovery operation of the photoreceptor 37 may also be performed before entering the plate-making mode. According to this method, the plate-making process continues after the copying cycle. It is particularly effective in recovering from fatigue.

This completes the plate-making process. During the plate-making process, in order to detect the image position and align it with the paper 85 during the printing process, the distance from the home position of the scroll drum 39 to the leading edge position of the image is determined by the clock. The number is counted and stored in advance in the memory of the control system. By correcting the paper feeding timing of the printing process paper 85 using this value, the image of the printing master and the paper 85 are aligned.

In addition, plate information such as the print master plate size and plate condition is stored in the memory of the control system, and this information is used to determine whether or not the next process is possible. 81 is not set, a message such as ``Cassette is full'' will be displayed, and this information can be erased if necessary, for example, by pressing the clear key and turning on the power switch. .

Therefore, by utilizing this, it is possible to perform multiple plate making of plates of different sizes and print overlay copying.

Next, the printing process will be explained.

The printing process is to perform electrostatic printing using the printing master created in the plate making process, and is similar to the copying operation described above, so it will be briefly explained.

However, unlike the copying operation, there is no exposure process for the original 2.
The rotation speed, paper feeding, and conveyance speed of the photoreceptor 37 are the fastest speed Pv4.

The print master that has reached the uniform exposure and static elimination lamp 31 by the rotation of the scroll drum 39 is transferred to the uniform exposure and static elimination lamp 31.
1 is turned on, it is uniformly exposed to light, and at this time, an electrostatic image for printing is formed in the image area. This electrostatic latent image is transferred to the developing device 55.
When the paper 85 is developed into a toner image by the developing rolls 55c and 55d, the paper 85 is transported from the paper cassette 81 by the paper transport mechanism 110, and the transfer device 140
is transferred within the transcription area of .

The paper 85 on which the toner image has been transferred is peeled off from the photoreceptor 37 by a peeling belt 131, and then transferred to a vacuum suction conveyance means 145.
The paper 85 is conveyed to the fixing device 160, where the toner image is fixed on the paper 85, and then discharged onto the paper discharge tray 176 by the discharge roll 175.

On the other hand, the photoreceptor 37 from which the paper 85 has been peeled off is again exposed to light by the uniform exposure/discharging tube 51 to form an electrostatic image in the image area, and then the toner image is transferred to the paper 85 through a development and transfer process.

That is, the printing process in which the toner image formed on the print master is transferred to the paper 85 by high-speed (PVA) rotation and fixed is repeated for a preset number of prints. optical fatigue increases and image density gradually decreases.

Therefore, in this embodiment, a potential detector 200 for detecting the surface potential of the master is provided above the negative exposure/static charge removal chamber 51, and based on the potential detected by this potential detector 200, the following operation is performed. is under control.

In other words, when producing the master in the above-mentioned plate-making process, the 70th
As shown in FIG. 2B, a patch 37b corresponding to the standard density is formed on the non-image area 37a of the photoreceptor 37 by the reflected light from the standard density reflecting plate 201, and this patch 37b is developed and fixed.

Then, during the printing process, the density of this patch 37b is detected by a potential detector 200, and a comparator 20 shown in Fig. 70 (a)
Import into 2.

A reference value is inputted to the comparator 202 in advance, and the taken-in potential and the reference value are compared, and the deviation thereof is output to the control means 203 that controls the uniform exposure and charge removal unit 51.

The control means 203 controls the uniform exposure and static elimination lamp 51 so that the amount of light emitted from the uniform exposure and static elimination lamp 51 is low when the signal detected by the potential detector 200 is lower than the reference value, and conversely increases when the signal detected by the potential detector 200 is higher than the reference value. Power supply 2 that supplies power to 51
04 to recover from fatigue of the master so that the patch density becomes the reference density, thereby making it possible to always obtain printed matter with a constant density even if the number of printed sheets increases.

FIG. 70(c) shows the relationship between the reference density portion potential and the amount of light from the uniform exposure/discharging chamber 51, and FIG. 70(d) shows the relationship between the reference density portion potential and the number of printed sheets.

FIG. 70(E) shows another embodiment in which a light amount sensor 206 for detecting the amount of light emitted from the - mode exposure/static charge removal lamp 51 is provided to correct variations in the amount of light emission. The light emitted from the sensor 51 is detected by a light amount sensor 206 and taken into a comparator 207, where it is compared with a reference value.

If there is a difference from the reference value, the deviation is output to the power source 204 of the uniform exposure/discharging lamp 51, and control is performed so that variations in the amount of light emitted are corrected.

On the other hand, the fixing speed of the fixing device 160 is constant during both the copying process and the printing process, and the speed difference that occurs during the printing process is absorbed by the vacuum suction conveying means 145 that conveys the paper 85 to the fixing device 160.

Further, the heat source 163 built into the fixing roll 161 of the fixing device 160 is controlled as follows.

An alternating current voltage as shown in FIG. 60 is applied to the heat source 163, and while the heat source 163 is energized, the voltage applied is set to a minimum of one half cycle of the power supply frequency, and the number of turns on and the number of turns off is controlled. Extraction control is performed.

The purpose of performing this draining control is to maintain the startup characteristics of the fixing device 160 and keep the power consumption within a specified range, for example, 15A. This is because the power variation is set to ±1% or more by selecting . In addition, the timing for removing the screen excludes the period from when the fuser roll 161 is cooled down to when power is started until the fixing possible signal is output, and from the time when the fixing impossible signal is issued until the fixing possible state is restored. This is limited to when the power supply voltage is equal to or higher than the specified value (95V) while the fixing device 160 is on.

As a control device for performing the above control, for example, a circuit shown in FIG. 81 is used. The control circuit uses the synchronizing pulse vB of the power supply.
and a power supply voltage vs are input, and when the power supply voltage is above a specified value, the power transistor Q3 provided on the output side is turned on and off, and when the power transistor Qs is on, draining is performed. That is, the heat source 163 is controlled to be turned off while the transistor Qs is turned on.

When the printing of a predetermined number of sheets is completed by the above operation, a cleaning process begins and the print master is illuminated by the monomorphic light and static elimination lamp 5.
The developing roll 55c is reversely charged after being neutralized by step 2.
, 55d, and the toner adhering to the image is removed. Thereafter, the photoreceptor 37 is rolled up, but by selecting "plate fixation" in advance, the photoreceptor 37 can be prevented from being rolled up. This makes it possible to start the printing process again using the same print master, and also enables multiple printing in which a new plate is created on an already created print master.

Next, the winding operation of the photoreceptor 37 will be explained.
Black segment marks 37a, as shown in FIG. 59, are displayed at equal intervals on the edge. Note that a continuous end mark 37b is displayed at the extreme end. - The photoreceptor 37 is wound up by a winding motor, and the length of the photoreceptor 37 wound around the winding shaft 42 is as follows:
It is detected by reading the segment mark 37m with a reflective optical sensor. Also, in order to prevent the optical sensor from reading the black spot as the segment mark 37a,
The detection of the segment mark 37a is ignored for the first certain period of time, and control is performed based on the control clock of the main body 1, thereby preventing malfunctions due to speed fluctuations during winding.

Then, the segment mark signal is read three times or more and 40 or less times in succession, and when the white signal is read three times in succession, it is determined that the segment mark 37a is present, and the winding of the photoreceptor 37 is stopped.

Furthermore, 3 segment marks are added every 7.5 msec.
7m, and when black is read 40 times or more within 30 seconds after the start of winding, it is determined that the end mark 37b is detected, and the winding of the photoreceptor 37 is performed at a position 110" in the forward rotation direction from the home position, and the winding button is pressed. If the end mark 37a is detected after being pressed and before the end mark 37a is moved to this position, a message indicating that there is no photoreceptor 37 is displayed and a warning to replenish the photoreceptor 37 is given.

When the winding of the photoreceptor 37 is completed by the above operation, a new photoreceptor 37 is exposed on the surface of the scroll drum 39.
The state becomes ready for copying or printing, and copying and printing can be performed by selecting the copying or printing mode through the above operation.

Further, the remaining amount of the photoreceptor 37 in the scroll drum 39 can be confirmed by a slit provided on the end surface of the scroll drum 39, and at the end of the photoreceptor 37, the remaining amount of the photoreceptor 37 is displayed on the display section 181 saying "One more frame left". ” is displayed. If you press the winding button in this state, the message "Please replace the photoconductor" will be displayed, and the photoconductor 37
If the segment mark 37a is not detected for a certain period of time during winding, it is determined that the winding is defective, and this fact is displayed on the display section 181.

Similarly, if the clock signal is not output from the winding motor even after the winding operation starts, it will be displayed as a winding failure, and in order to prevent incorrect plate exchange or operation, press the winding button and press the clear button. Safety measures have been taken to ensure that winding is only started when the

Moreover, during winding, the feeding shaft 4 is
With the 0 side locked by a ratchet, the motor is rotated without any current limitation, and tension is applied to the photoreceptor 37.

To replenish the photoreceptor 37, first pull out the photoreceptor unit 35 from the main body 1, load a new roll of photoreceptor 37 onto the feeding shaft 40, and then pull out the photoreceptor 37 from the slit 39a.
7 is bypassed around the scroll drum 39, and then drawn into the scroll drum 39 again through the slit 39m,
Wind it onto the winding shaft 42.

In this state, when the photoconductor unit 35 is loaded into the main body 1 again and the front cover of the main body 1 is closed, the message "Please press the winding button" will be displayed on the display section 181. All you have to do is wind up 37.

Further, by performing the cleaning process after winding, it is possible to remove dirt such as toner adhering to the unfed photoreceptor 37, and when pressing the winding button after removing the jammed paper 85, By performing a cleaning process first and then rolling up the photoreceptor, it is possible to prevent stains.

Note that FIG. 62 shows the operation timing of each part during the copy mode, FIG. 63 shows the operation timing of each part during the refresh cycle, FIG. 64 shows the operation timing of each part during manual platemaking, and FIG. E FIG. 66 shows the operation timing of each section when forming two images, FIG. 66 shows the operation timing of each section in the print mode, and FIG. 67 shows the operation timing in the print mode.

〔Effect of the invention〕

As described in detail above, the present invention is an electrostatic printing device that has a copy mode and a print mode, and that rotates a photoreceptor at high speed during the print mode to improve printing speed, and detects the surface temperature of the photoreceptor. A detection means and a heating means for heating the photoreceptor are provided, and the heating means is controlled so that the surface temperature of the photoreceptor falls within a set range based on the signal detected by the detection means, and the fixing energy when making a master is controlled. This allows stable fusing to be performed without being affected by the surrounding environment or internal temperature of the machine, and this results in a master with high fusing strength, which prevents the toner image on the master from peeling off during printing. This makes it possible to resolve problems such as being unable to print.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is an overall perspective view, Fig. 2 is an enlarged cross-sectional view of the same, and Figs. 3 and 4 are partially omitted plan views showing the drive section of the optical system. , Figure 5 is a front view of the same,
Figure 6 is a side view of the same side, Figures 7 and 8 are explanatory diagrams of the operation of the top cover when it is opened and closed, Figure 9 is a sectional view of a portion of the top cover, and Figures 10 (a) and (b) are scroll drums. 11 is a perspective view of the charger, FIG. 12 is an enlarged view of the main part, FIG. 13 is a sectional view of the image area adjustment lamp, and FIG. 15 is a sectional view of the same, FIG. 16 is a plan view of the same, FIG. 17 is an explanatory view of the developing roll, FIG. 18 is a sectional view of the stirring roll, FIG. 19 is an explanatory view of the developing device, Figures 20 (a) to 2) are explanatory diagrams of the toner concentration detector, Figure 21 is a side view of the cross mixer, Figure 22 is a sectional view thereof, Figure 23 is an explanatory diagram of the auger, and Figure 24 is a developing diagram. A detailed diagram of the device, Figure 25 is a detailed diagram of the drive section, Figure 26 is an explanatory diagram of the agitator, Figure 27 (A),
(B), FIGS. 28 and 29 are explanatory diagrams of the developing unit positioning section, FIG. 30 is an explanatory diagram of the developer replenishment unit,
Figure 31 is the same plan view, Figures 32 (a), (b), and 33.
37 to 37 are explanatory diagrams of the paper feeding means, FIGS. 38 and 39 are detailed diagrams of the paper transport mechanism, FIGS. 40 and 41 are explanatory diagrams of the paper guide section, and FIGS. 42 to 47 48 and 49 are illustrations of the transfer corotron, FIGS. 50 and 51 are illustrations of the vacuum suction conveyance means, and FIGS. 52 and 53 are illustrations of the fixing device. figure,
Figure 54 is a detailed diagram of the paper peeling mechanism, Figures 55 and 56.
The figure is an explanatory diagram of the discharge roll, Figures 57 and 58 are explanatory diagrams of the paper discharge tray, Figure 59 is an explanatory diagram of the photoreceptor, Figure 60 is an explanatory diagram of the weeping control, and Figure 61 is an explanatory diagram of the same control. A circuit diagram showing the circuit, FIGS. 62 to 67 are timing charts showing the operation, and FIGS. 68, 69 (A) to (E), and 70 (A) to E) are action explanatory diagrams. . 1 is the main body, 37 is a photoreceptor, 52 is a flash fixing device, 5
5 is a developing device. Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Masaaki Yonehara

Claims (1)

[Claims] In an electrostatic printing device that has a copy mode and a print mode, and prints using a master formed on the photoreceptor 37 by rotating the photoreceptor 37 at a faster speed in the print mode than in the copy mode, the photoreceptor 37 A detection means for detecting the surface temperature of the photoreceptor 37 and a heating means for heating the photoreceptor 37 are provided,
An electrostatic printing device that controls a heating means so that the temperature of the photoreceptor falls within a set range based on a detection signal detected by the detection means, and also controls the fixing energy of a flash fixing device 52 when making a master.