JPH0822203A - Electrophotographic device and electrophotographic method - Google Patents

Abstract

PURPOSE:To provide an electrophotographic device and an electrophotographic method capable of printing in consideration of the kind and the thickness of a recording medium. CONSTITUTION:An electrophotographic printer applying the electrophotographic device and the electrophotographic method is provided with an intermediate transfer drum 66 which is rotated in contact with a photoreceptor drum 24, an electric motor 106 used for these drums in common, a controller 108 for controlling the rotation of the electric motor 106, a kind sensor 120 electrically connected with the controller 108 and prepared for detecting the kind of the recording medium, a thickness sensor 110 for detecting the thickness of the recording medium, a kind setting device 122 and a thickness setting device 112 for respectively setting the kind and the thickness of the recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus and an electrophotographic method applied to a color laser printer, a color copying machine or the like.

[0002]

2. Description of the Related Art A color type electrophotographic apparatus is provided with a photosensitive drum as a photosensitive medium on which a toner image is formed, and an intermediate transfer drum, for example, as an intermediate transfer member. It is designed to rotate while rolling. Toner images of different colors are sequentially formed on the photosensitive drum, and these toner images are transferred from the photosensitive drum onto the intermediate transfer drum in an overlapping manner. Therefore, a plurality of color toner images, that is, color images, are formed on the intermediate transfer drum, and thereafter, the color images on the intermediate transfer drum are collectively transferred and fixed on a recording sheet as a recording medium, and then transferred to the recording sheet. Color printing is completed.

[0003]

When a color toner image is transferred and fixed on a recording paper, the presence or absence of a coating layer on the surface of the recording paper, the thickness of the coating layer, and the thickness of the recording paper itself must be taken into consideration. desired. Further, when the recording medium is not an ordinary paper but an overhead projector OHP film, tack paper, non-woven fabric, etc., the conditions for transferring and fixing the toner image to the recording medium are largely different, and the material and the structure of the recording medium are different. Should also be considered. In particular, when the recording medium is an OHP film, the thermal conductivity of the recording medium is significantly different from that of plain paper. Therefore, when transferring and fixing a color toner image, the melting time of toner particles is longer than that of plain paper. You have to secure enough.

However, the intermediate transfer drum is rotated at the same peripheral speed as the photosensitive drum in order to stably receive the toner image on the photosensitive drum, and the color toner image is transferred from the intermediate transfer drum onto the recording medium. The time required for fixing, that is, the time that can be secured for melting the toner particles is constant regardless of the type of recording medium. For this reason, there is a problem that the color toner image suitable for the recording medium cannot be transferred or fixed.

The present invention has been made in view of the above-mentioned circumstances. The first object of the present invention is to provide an electrophotographic apparatus and an electronic photography apparatus for performing printing in consideration of the type of recording medium, that is, its material and configuration. To provide a photographic method. A second object is to provide an electrophotographic apparatus and an electrophotographic method that perform printing in consideration of the thickness of the recording medium in addition to the type of the recording medium.

Here, the type of recording medium means plain paper,
In addition to the difference in composition such as coated paper or uncoated paper showing the presence or absence of a coating layer on the plain paper surface, and slightly coated paper in between, OHP film, non-woven fabric, aluminum sheet, etc. It indicates the type due to the difference in material.

[0007]

In order to achieve the first object, the electrophotographic apparatus of the present invention (claim 1) is a switching means for changing the moving speed of the intermediate transfer member according to the kind of the recording medium. In the electrophotographic method (claim 6) of the present invention, the moving speed of the intermediate transfer member is changed according to the type of the recording medium.

In order to achieve the second object, the electrophotographic apparatus of the present invention (claim 2) is provided with a switching means for changing the moving speed of the intermediate transfer member according to the type and thickness of the recording medium. And the electrophotographic method of the present invention (claim 7)
Changes the moving speed of the intermediate transfer member according to the type and thickness of the recording medium. In the case of the electrophotographic method, the type of the recording medium is discriminated by the difference in the material and the constitution of the recording medium (claim 8).

In the electrophotographic apparatus (claim 3), the switching means is provided with an input means for inputting the type of the recording medium, and the input means detects the type based on the difference in material and structure of the recording medium. Means can be included (claim 4). Further, the input means can include setting means for selecting a type based on a difference in material and configuration of the recording medium (claim 5).

[0010]

According to the electrophotographic apparatus and the electrophotographic method of the above-mentioned claims 1 and 6, when the toner image is transferred and fixed from the intermediate transfer member to the recording medium, the moving speed of the intermediate transfer member is set to the moving speed of the recording medium. Set the speed suitable for the type. According to the electrophotographic apparatus and the electrophotographic method of claims 2 and 6, when the toner image is transferred and fixed from the intermediate transfer member to the recording medium, the moving speed of the intermediate transfer member is set to the type and thickness of the recording medium. Set to a suitable speed.

According to the electrophotographic apparatus and the electrophotographic method of claims 3, 4, 5 and 8, whether the type based on the difference in the material and the configuration of the recording medium is detected by the detecting means and discriminated.
Alternatively, the setting means determines.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a color type electrophotographic printer is schematically shown. The electrophotographic printer is roughly divided into a printer body 2 and a paper drawer unit 4. The printer body 2 is fixedly placed on the upper surface of the drawer unit 4, and the drawer unit 4 is
Along with the printer body 2, it can be moved on the floor via a plurality of casters 6.

The drawer unit 4 includes drawers 8 in upper and lower stages,
The drawers 8 and 10 accommodate various recording media. Here, as the recording medium, plain paper, recycled paper, art paper, thermal transfer paper, coated paper, non-coated paper, slightly coated paper, OHP film, tack paper, non-woven fabric and the like are used. Further, the drawers 8 and 10 have recording medium feeding units 14 and 16 built therein.
16 removes the recording media one by one from the drawer,
Then, the recording medium is loaded into the printer main body 2 through the carry-in path 1
You can lead to 2. In addition, these feeding units 1
Reference numerals 4 and 16 are simply shown by broken lines in FIG.

The carry-in path 12 is composed of a plurality of rollers, a guide plate, and the like, and extends above the process unit 18 located in the upper part of the printer body 2.
The process unit 18 includes a casing 22,
In the casing 22, a photosensitive drum 24 as a photosensitive medium, a cleaner 26 located around the photosensitive drum 24, a charge eliminator 28, and a charger 30 are provided. These cleaner 26, static eliminator 28 and charger 30
Are sequentially arranged from the top of the photosensitive drum 24 in the rotation direction of the photosensitive drum 24 indicated by the arrow in FIG.

The outer peripheral surface of the photosensitive drum 24 is formed of a photosensitive layer made of an organic photosensitive material, and a part of the outer peripheral surface thereof projects from the lower surface of the process unit 18.
The static eliminator 28 is, for example, a small incandescent lamp that neutralizes the outer surface of the photosensitive drum 24, while the charger 30 charges the outer surface of the photosensitive drum 24 to a uniform predetermined potential by corona discharge. it can.

The casing 22 is movably supported by a pair of guide rails 32, and if necessary, as shown in FIG.
It can be pulled out to the front side of the printer body 2 when viewed. Further, in the printer body 2, a developing unit 36 and an exposure unit 38 are arranged below the process unit 18. The exposure unit 38 has an L-shaped casing 39 that surrounds the developing unit 36 from the lower side. Although not shown in the casing 39, in addition to the laser light source, the laser light from the laser light source is used. An optical system leading to the emission unit 40, a reflection mirror, and the like are housed. Here, the laser light from the emitting portion 40 is, as indicated by the one-dot chain line in FIG. 1, seen from the rotation direction of the photosensitive drum 24, the outer surface of the photosensitive drum 24 located on the rotation-in side of the charger 30. That is, the photosensitive layer is irradiated.

The exposure unit 38 is electrically connected to an image data creating circuit (not shown), and this image data creating circuit is connected to a computer. When the electrophotographic apparatus of the present invention is applied to a color copying machine,
It goes without saying that the image data creating circuit is connected to the head section of the color scanner. The image data generating circuit color-separates the color print information obtained from the head of the computer or the color scanner, and sequentially supplies the color-separated print information to the exposure unit 38.

On the other hand, the developing unit 36 is arranged immediately below the process unit 18 as is apparent from FIG. 1, and four developing units are provided corresponding to the color separation of the color print information in the above-mentioned image data creating circuit. 42Y, 42M, 42C,
It is equipped with 42B. These developing devices 42 are arranged in the horizontal direction in FIG. 1, and each developing device 42 is provided with a toner supplying / discharging portion 46 and a toner cartridge 44 from the top thereof. The toner supplying / discharging unit 46 has a developing roller 50 and a squeeze roller 52 which are capable of rolling contact with the photosensitive drum 24, and the toner cartridge 44 stores liquid toner.

Here, the toner cartridge 44 of each developing unit 42 has a color obtained by dispersing yellow (Y), magenta (M), cyan (C), and black (B) toner particles in a liquid carrier. Different liquid toners are stored respectively, and the subscripts Y, M, C and B of the developing device 42 indicate the types of toner particles in the liquid toner. In each developing device 42, the delivery of the liquid toner performed between the toner supply / discharge unit 46 and the toner cartridge 44, and the configuration of the drive system of the developing roller 50 and the squeeze roller 52 are not shown, but each developing device is not shown. Vessel 42
, The liquid toner in the toner cartridge 44 is supplied to the toner supply / discharge unit 46, while the surplus liquid toner is returned to the toner cartridge 44. Further, the developing roller 50 and the squeeze roller 5 are used.
2 is rotated at a predetermined magnification with respect to the peripheral speed of the photosensitive drum 24. Further, in addition, the developing roller 50 and the photosensitive drum 24 are rotated so that their opposing peripheral surfaces move in the same direction. Squeeze roller 5
2 and the photosensitive drum 24 are rotated so as to move in the opposite circumferential surfaces or in the opposite directions. Further, the toner cartridge 44 is mounted so as to be removable so as to replenish the liquid toner.

Further, the entire developing unit 36 is supported by a horizontal feed screw 56 via a pair of support legs 54. Both ends of the feed screw 56 are rotatably supported, and a forward / reverse rotatable drive motor 58 is provided at one end of the pair of pulleys 6.
0 and 62 and a drive belt 64 are connected. Therefore, when the drive motor 58 is rotated in one direction, this rotational force also moves the feed screw 56 in one direction, and the developing unit 36 as a whole is shown in FIG.
When the drive motor 58 is rotated in the right direction and the drive motor 58 is rotated in the opposite direction, the entire developing unit 36 is moved to the left side in FIG.

By the reciprocating movement of the developing unit 36 described above, each developing device 42 is selectively positioned immediately below the photosensitive drum 24, and at this time, the developing roller 50 and the squeeze roller 52 have a predetermined gap in the photosensitive drum 24. Be opposed. In the state of FIG. 1, the developing device 42B is positioned directly below the photosensitive drum 24. The process unit 18 described above further includes an intermediate transfer drum 66 as an intermediate transfer member in addition to the photosensitive drum 24, and the intermediate transfer drum 66 is in rolling contact with the photosensitive drum 24. The intermediate transfer drum 66 has a larger diameter than the photosensitive drum 24, and a part of the outer peripheral surface thereof projects upward from the upper surface of the process unit 18.

A hot roller 68 having a built-in heater (not shown) is provided on the protruding outer peripheral surface of the intermediate transfer drum 66.
Can be rolled and contacted, and the downstream end of the carry-in path 12 described above is positioned near the rolling contact point between the intermediate transfer drum 66 and the hot roller 68. The hot roller 6
8 is supported by a pressing mechanism (not shown). This pressing mechanism normally applies a predetermined pressing force to the hot roller 68, which is positioned with a predetermined gap from the intermediate transfer drum 66, with a predetermined pressing force. It can be pressed against 66.

As shown in FIG. 2, the intermediate transfer drum 66 includes a metal drum main body 70, and an intermediate transfer sheet 72 attached to the outer peripheral surface of the drum main body 70 leaving both ends thereof. The intermediate transfer sheet 72 defines a printable area. As shown in FIG. 3, the intermediate transfer sheet 72 has a cushion layer 74 made of conductive rubber that adheres to the outer peripheral surface of the drum body 70.
And has a two-layer structure of a silicone resin layer 76 that covers the cushion layer 74 and is thinner than the cushion layer 74 and has an electrical insulation property. Therefore, the intermediate transfer drum 66
The outer peripheral surface of is substantially electrically insulating.

The intermediate transfer sheet 72 is not adhered over the entire circumference of the drum body 70, and as shown in FIG. A predetermined interval 78 is secured in the. The space 78 can also be used as a space for disposing the attachment of the intermediate transfer sheet 72 to the drum body 70.

Further, a pair of spacer sheet pieces 90 are attached to the outer peripheral surface of the drum body 70 at both ends thereof. These spacer sheet pieces 90 have the same thickness as the intermediate transfer sheet 72, and extend from one edge of the intermediate transfer sheet 72 to the other edge,
The step existing on the outer peripheral surface of the intermediate transfer drum 66, that is, the step caused by the interval 78 is compensated. Therefore, irrespective of the presence of the gap 78 between the intermediate transfer sheets 72, the intermediate transfer drum 66 can rotate while closely adhering to the photosensitive drum 24, and the intermediate transfer drum 66 and the photosensitive drum 24 are always smoothly moved. Can be rotated.

Intermediate transfer drum 66 and photosensitive drum 24
Have drum shafts 92 and 94, respectively, and one ends of these drum shafts 92 and 94 rotate on support frames 96 in the printer body 2 via bearings 98, respectively, as shown in FIG. It is supported freely. In addition,
Although not shown, it goes without saying that the other ends of the drum shafts 92 and 94 are also rotatably supported in the same manner.

The drum shafts 92 and 94 respectively project from the support frame 96, and gears 100 and 102 for power transmission that mesh with each other are attached to the projecting ends thereof. Further, in the case of this embodiment, the protruding end of the drum shaft 92 is connected to the output shaft of the electric motor 106 such as a pulse motor or a DC motor via the coupling 104. The electric motor 106 can be connected to the drum shaft 94 on the photosensitive drum 24 side via a coupling.

When the electric motor 106 is rotated, the gear 1
Due to the meshing of 00 and 102, the intermediate transfer drum 66 and the photosensitive drum 24 rotate at the same first peripheral speed while rollingly contacting each other in the direction of the arrow shown in FIG. The electric motor 106 is electrically connected to a controller 108. Although not shown, the controller 108 includes a CPU, a ROM, a RAM, various input / output interfaces, etc., and constitutes the above-mentioned image data creating circuit, Process unit 18 and developing unit 3
6, that is, the drive motor 58, and the exposure unit 38
Control the operation of. Therefore, the controller 108
Is capable of receiving color print information from a computer or the head of a color scanner, and is electrically connected to the developing unit 36 and the exposure unit 38.

A radiation thickness gauge, that is, a thickness sensor 110, a thickness setting device 112, and a print quality setting device 113 are electrically connected to the controller 108.
The thickness sensor 110 detects the thickness of the recording medium conveyed from the drawer unit 4 to the process unit 18 via the carry-in path 12, and outputs the sensor signal, that is, the thickness of the recording medium. Supply to the controller 108. As shown in FIG. 1, the thickness sensor 110
Is the process unit 1 even in the carry-in route 12, for example.
It is located on the 8th side.

The thickness setting device 112 is incorporated in, for example, an operation panel (not shown) of the printer body 2,
When the thickness of the recording medium housed in each of the drawers 8 and 10 of the drawer unit 4 is known, the user operates the thickness setter 112 to set the thickness of the recording medium used for printing. Can be given to the controller 108 as

The print quality setting device 113 is also incorporated in the operation panel of the printer main body 2, and the user operates the print quality setting device 113, and at the time of printing, the controller sets the required print quality level as a selection signal. 108. Furthermore, a type sensor 120 and a type setting device 122 are electrically connected to the controller 108. The type sensor 120 detects the type of the recording medium due to the difference in the material and the configuration of the recording medium,
The sensor signal is supplied to the controller 108. FIG.
The type sensor 120 is a thickness sensor 1 as shown in FIG.
It is interposed in the conveyance path 12 near 10 and is specifically configured by combining a transmissive optical sensor and a reflective optical sensor.

The type setting device 122 is incorporated in the operation panel of the printer main body 2 like the thickness setting device 112, and the type of the recording medium accommodated in each drawer 8, 10 of the drawer unit 4 is known. In some cases, the user can operate the type setting device 122 to give the type of the recording medium used for printing to the controller 108 as a setting signal.

Further, the controller 108 includes a rotation angle sensor 11 for detecting the rotation angle of the intermediate transfer drum 66.
4 is electrically connected. This rotation angle sensor 114
Is a reflection type optical sensor including a combination of a light emitting element and a light receiving element, and as shown in FIG. 4, the intermediate transfer drum 6 is seen in the circumferential direction of the drum shaft 92.
6 and the photosensitive drum 24 are fixedly arranged at the same rotation angle position as the rolling contact point.

On the other hand, the drum shaft 92 has the drum shaft 9
The index arm 116 that rotates integrally with the 2 is attached.
The drum shaft 92 extends radially outward of the drum shaft 92.
That is, with the rotation of the intermediate transfer drum 66, the tip portion thereof rotates so as to cross the sensor portion of the rotation angle sensor 114.

As is apparent from the sector shown by the chain line of two points in FIG. 5, when viewed in the circumferential direction of the intermediate transfer drum 66, the index arm 116 and the gap 78 between the intermediate transfer sheet 72 in the intermediate transfer drum 66, that is, The rotation phases of the spacer sheet pieces 90 are the same. As a result, the sensor portion of the rotation angle sensor 114 has the index arm while the spacer sheet piece 90 of the intermediate transfer drum 66 is in rolling contact with the photosensitive drum 24, that is, while the interval 78 passes through the photosensitive drum 24. Shielded from 116,
At this time, the rotation angle sensor 114 outputs an ON signal to the controller 108. Further, when the spacer sheet piece 90 of the intermediate transfer drum 66 is not in rolling contact with the photosensitive drum 24, the sensor portion of the rotation angle sensor 114 is not blocked by the index arm 116, and at this time, the rotation angle sensor 114 outputs an off signal. Is output to the controller 108.

Referring again to FIG. 1, the intermediate transfer drum 6
A transfer charger 80 having a structure similar to that of the charger 30 of the photosensitive drum 24 is disposed around the photosensitive drum 24. The transfer charger 80 is disposed on the rotary feed side of the intermediate transfer drum 66 with respect to the photosensitive drum 24. , The intermediate transfer sheet 72 of the intermediate transfer drum 66 is uniformly charged. Further, around the photosensitive drum 24, an auxiliary squeeze roller 81 and a cleaner charger 82 are arranged between the developing unit 36 and the cleaner 26 as viewed in the rotation direction of the photosensitive drum 24. Here, if the description of the cleaner 26 is added, the cleaner 26 includes a cleaning roller 83 that contacts the photosensitive drum 24, and an aluminum recovery roller 84 that contacts the cleaning roller 83. The cleaning roller 83 has an average diameter of 50 μm. The rubber roller has a large number of micro holes.

Further, from the hot roller 68 and the intermediate transfer drum 66 described above, a cut-out sheet discharge path 86 extends toward the discharge port 85 of the printer body 2. The bypass route 87 is branched from the middle of the carry-out route 86,
The bypass path 87 is connected to the carry-in path 12. The bypass path 87 can be opened and closed by a switching claw 88 arranged at a branch portion with the carry-out path 86.

Next, the operation of the above electrophotographic printer will be described. First, the photosensitive drum 24 and the intermediate transfer drum 66 are rotated while rollingly contacting each other at the first peripheral speed. At this time, the developing unit 36 moves to the right from the state of FIG. Photosensitive drum 2
It is assumed that it is located directly below 4.

In this state, the outer peripheral surface of the photosensitive drum 24 is uniformly charged by the charger 30 after the residual liquid toner and the residual charge are removed by the cleaner 26 and the static eliminator 28. The outer peripheral surface of the photosensitive drum 24 that has passed through the charger 30 is scanned by the laser light from the exposure unit 38. In this case, the outer peripheral surface of the photosensitive drum 24 is scanned based on the color-separated print information, that is, the yellow print information. A latent image is formed. When the electrostatic latent image formed in this way passes through the developing device 42Y of the developing unit 36, it is developed with liquid toner supplied from the developing roller 50 to become a yellow toner image, and the photosensitive drum 24 The surplus liquid toner above is added to the squeeze roller 52 of the developing unit 42Y and the auxiliary squeeze roller 8
Removed by 1.

The rotation of the photosensitive drum 24 further progresses, and the yellow toner image is transferred to the photosensitive drum 24 and the intermediate transfer drum 66.
When it reaches the transfer contact point with, that is, the transfer position, the yellow toner image is transferred to the intermediate transfer sheet 72 of the intermediate transfer drum 66.
Is transferred to Intermediate transfer sheet 7 of the intermediate transfer drum 66
By charging 2 by the transfer charger 80, the influence of the toner image already transferred on the intermediate transfer sheet 72 is canceled, and the next toner image having a different hue is easily transferred from the photosensitive drum 24. At the same time, the toner image on the intermediate transfer sheet 72 is prevented from returning to the photosensitive drum 24.

Since the intermediate transfer sheet 72 does not exist on the entire circumference of the intermediate transfer drum 66 as described above,
It goes without saying that the toner image is transferred from the photosensitive drum 24 to the intermediate transfer drum 66 while avoiding the interval 78 of the intermediate transfer sheet 72. After that, the above-described process from the formation of the toner image on the photosensitive drum 24 to the transfer of the toner image from the photosensitive drum 24 to the intermediate transfer drum 66 is performed on the print information in which magenta, cyan, and black are separated. On the basis and also using the corresponding developer 42. Therefore, the intermediate transfer drum 66
On the intermediate transfer sheet 72, a color toner image in which toner images of four colors are superposed is formed.

When the transfer of the toner image to the intermediate transfer drum 66 is completed, the final transfer / fixing process of the color toner image from the intermediate transfer drum 66 to the recording medium is performed thereafter. Before, the controller 108 executes a rotation speed control routine of the intermediate transfer drum 66 shown in FIG. 6, and this rotation control routine will be described below.

Rotational speed control routine: In this routine, the controller 108 reads various setting signals selected by the thickness setting device 112, the print quality setting device 113 and the type setting device 122 (step S1). In parallel with the execution of this routine, in order to prepare for the final transfer / fixing process, the recording medium is fed from one drawer of the drawer unit 4 to the intermediate transfer drum 66 through the carry-in path 12 of the printer body 2. When the recording medium is supplied and passes through the thickness sensor 110 and the type sensor 120, the thickness sensor 110 and the type sensor 1
20 outputs the sensor signals indicating the thickness and type of the recording medium, respectively, and at this time, the controller 108 reads the sensor signals from the thickness sensor 110 and the type sensor 120 (step S2).

If the thickness and type of the recording medium used for printing have already been set by the thickness setter 112 and the type setter 122, the controller 1
Reference numeral 08 designates the thickness and type of the recording medium based on the setting signals from the thickness setting device 112 and the type setting device 122, or sets those signals and the thickness sensor 1.
By combining 10 and the sensor signals from the type sensor 120, the thickness of the recording medium and the type thereof can be detected with high accuracy. That is, if a setting signal is given to the controller 108 from the thickness setter 112 or the type setter 122, the controller 108 changes the detection sensitivity of the thickness sensor 110 or the type sensor 120 to a level suitable for the recording medium. You can also
When the level of the setting signal and the level of the sensor signal are inconsistent, it is possible to notify the user of a setting error in the setting device or a sensor failure.

At the next step S3, each setting device 112,
Setting signals from 113 and 122 and each sensor 110,
In response to the sensor signal from 120, the electric motor 106
The acceleration / deceleration amount of is determined. Specifically, since the absorption rate of the liquid toner and the smoothness of the surface of the recording medium are different due to the difference in the material and the structure of the recording medium, the liquid toner hardly absorbs like the OHP film or the aluminum sheet. In the case of a recording medium, the acceleration / deceleration amount is a large deceleration amount. Although the recording medium has a lower absorption rate of the liquid toner than the plain paper, the acceleration / deceleration amount is smaller than that of the OHP film or the aluminum sheet, though not as much as that of the OHP film or the aluminum sheet. further,
As the smoothness of the surface of the recording medium decreases, the acceleration / deceleration amount of the electric motor 106 increases.

In step S3, the amount of acceleration / deceleration of the electric motor 106 is set depending on the thickness of the recording medium, and as the thickness increases, the amount of acceleration / deceleration becomes a large amount of deceleration, and high-quality printing is performed. For example, when gloss is required as the quality, the amount of acceleration / deceleration of the electric motor 106 is a large amount of deceleration. On the other hand, in the case of a recording medium having a high absorption rate of liquid toner and a high degree of surface smoothness, the acceleration / deceleration amount of the electric motor 106 is set to 0 or becomes the acceleration amount, and the thickness of the recording medium is thin. When high-quality printing is not required, it is possible to set the acceleration / deceleration amount to the acceleration side.

In the next step S4, it is determined whether or not all the toner images of respective colors have been transferred from the photosensitive drum 24 to the intermediate transfer drum 66, that is, whether or not the image forming process has been completed. The determination here can be made by the controller 108 monitoring the operations of the developing unit 36 and the exposure unit 38. If the determination result of step S4 is false (No), the routine immediately exits,
On the contrary, if the determination result is true (Yes), the controller 108 reads the detection signal of the rotation angle sensor 114 (step S5), and determines whether or not it is immediately after the detection signal is switched from off to on. Yes (Step S
6). If the determination result here is false, step S5
After this, the determination of step S6 is repeatedly performed, and when the determination result becomes true, the next step S6 is performed.
7 is carried out.

In step S7, the controller 10
8 increases or decreases the rotation speed of the electric motor 106 based on the acceleration / deceleration amount of the electric motor 106 obtained in step S3,
The rotation speed of the intermediate transfer drum 66, that is, its peripheral speed is changed to a speed suitable for the type and thickness of the recording medium. The rotation angle sensor 114 outputs an ON signal when the space 78 between the intermediate transfer sheets 72 on the intermediate transfer drum 66 is passing through the rolling contact point with the photosensitive drum 24, and step S6 is performed by the rotation angle sensor 114. Since it is determined whether or not the output has just been switched from off to on,
The next step S7, that is, the rotation speed control of the intermediate transfer drum 66 is performed while the interval 78 of the intermediate transfer sheet 72 passes through the rolling contact.

When step S7 is carried out, the rotation control routine of FIG. 6 is terminated, after which the above-mentioned final transfer / fixing process is carried out. In this final transfer / fixing process, first, the hot roller 68 is pressed against the intermediate transfer drum 66 with a predetermined pressing force, and in this state, the carry-in path 12
When the recording medium conveyed above or the recording medium already waiting in the conveying path 12 passes between the hot roller 68 and the intermediate transfer drum 66, the intermediate transfer drum 6
The color toner image on the intermediate transfer sheet 72 of No. 6 is heated and pressed to be transferred onto the recording medium and fixed at the same time, and the color printing on the recording medium is completed.

Since the peripheral speed of the intermediate transfer drum 66 is determined according to the type and thickness of the recording medium, the toner particles of the color toner image on the intermediate transfer sheet 72 and the recording medium are hot rollers. The pressure and heating action of 68 is sufficiently received, and the transfer and fixing of the color toner image to the recording medium can be performed well. On the contrary, when high-quality printing is not required, the peripheral speed of the intermediate transfer drum 66 is increased, which has the advantage of shortening the time required for printing on the recording medium.

Since the intermediate transfer drum 66 and the photosensitive drum 24 are rotated by the common electric motor 106, when the peripheral speed of the intermediate transfer drum 66 is controlled to be switched, the peripheral speed of the photosensitive drum 24 is simultaneously switched. Therefore, in principle, no deviation occurs in the peripheral speeds of the intermediate transfer drum 66 and the photosensitive drum 24. Therefore, since the photosensitive drum 24 and the intermediate transfer drum 66 do not rub each other, the deterioration of the photosensitive drum 24, that is, the outer peripheral surface thereof is not promoted, and the photosensitive drum 2 is prevented.
4 can be extended.

Moreover, the peripheral speed switching control of the intermediate transfer drum 66 is performed while the interval 78 of the intermediate transfer sheet 72 is passing through the rolling contact point between the intermediate transfer drum 66 and the photosensitive drum 24. A pair of gears 10 forming a power transmission system between the transfer drum 66 and the photosensitive drum 24.
Even if the meshing of 0 and 102 becomes unstable due to the backlash and the peripheral speeds of the intermediate transfer drum 66 and the photosensitive drum 24 are deviated from each other, the color toner image on the intermediate transfer sheet 72 becomes a photosensitive drum. It is not rubbed by 24. Therefore, since the color toner image is not disturbed, the color toner image can be stably transferred and fixed on the recording medium, and the life of the intermediate transfer sheet 72 can be extended at the same time.

Thereafter, the printed recording medium is guided through the carry-out path 86 and discharged from the paper discharge port 85 of the printer body 2. After the color printing on the recording medium is completed, the peripheral speeds of the intermediate transfer drum 66 and the photosensitive drum 24 are returned to the first peripheral speed. In this case, the return to the first peripheral speed is performed by the photosensitive drum. The process is finished by the time the writing of the electrostatic latent image on the drum 24 is started.

Further, in the case of this embodiment, since the carry-in path 12 and the carry-out path 86 are connected via the bypass path 87, if the bypass path 87 is opened, the printed cuts are printed. The paper can be returned to the carry-in path 12 again. In this case, since the printed surface of the cut sheet returned to the carry-in path 12 faces upward, if the final transfer / fixing process is similarly repeated for the cut sheet, the cut sheet is cut. Double-sided printing is possible.

The present invention is not limited to the above-described embodiment, but various modifications can be made. For example,
The present invention is applied to an electrophotographic printer using a wet type developing unit, a laser type exposing unit and a drum type intermediate transfer member. However, the developing unit may be a dry type and the exposing unit may be a light source for the developing unit. In addition, an LED array composed of light emitting diode elements (LEDs) can be used, and the intermediate transfer member can be composed of an endless belt.

Further, the sensor for detecting the type and thickness of the recording medium, the sensor for detecting the rotation angle of the intermediate transfer drum 66, etc. are not limited to those described above, and various types of sensors can be used. is there.

[0057]

As described above, according to the electrophotographic apparatus and the electrophotographic method of the present invention, the image forming process for transferring to the intermediate transfer member and the toner image on the intermediate transfer member are finally recorded on the recording medium. In the fixing process of transferring / fixing, the moving speed of the intermediate transfer member is changed based on the type of the recording medium, specifically, the material and the configuration thereof.
Printing can be performed under optimum conditions for the recording medium.
In addition to the type of recording medium, the moving speed of the intermediate transfer member
If the thickness is changed in consideration of the thickness, printing on the recording medium can be more favorably performed, and the print quality can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an entire electrophotographic printer.

FIG. 2 is a perspective view showing an intermediate transfer drum of an electrophotographic printer.

FIG. 3 is a cross-sectional view showing a part of the outer circumference of the intermediate transfer drum.

FIG. 4 is a schematic configuration diagram showing a drive control system of an intermediate transfer drum.

FIG. 5 is a diagram showing an attachment position of an index arm and a rotation angle sensor of the drum shaft of the intermediate transfer sheet of the intermediate transfer drum.

FIG. 6 is a flowchart showing a rotation speed control routine of the intermediate transfer drum.

[Explanation of symbols]

 2 Printer body 4 Drawer unit 6 Casters 8, 10 Drawer 12 Carry-in path 14, 16 Feeding unit 18 Process unit 22 Casing 24 Photosensitive drum (photosensitive medium) 26 Cleaner 28 Charger 30 Charger 32 Guide rail 36 Developing unit 38 Exposure unit 39 Casing 40 Ejection Section 42Y, 42M, 42C, 42B Developing Unit 44 Toner Cartridge 46 Toner Supply / Discharge Section 50 Developing Roller 52 Squeeze Roller 54 Support Leg 56 Feed Screw 58 Drive Motor 60, 62 Pulley 64 Drive Belt 66 Intermediate Transfer Drum ( Intermediate transfer body) 68 Hot roller 70 Drum body 72 Intermediate transfer sheet 74 Cushion layer 76 Silicone resin layer 78 Interval 80 Transfer charger 81 Auxiliary squeeze roller 82 Cleaner charger 3 Cleaning Roller 84 Collection Roller 85 Ejection Port 86 Carry Out Route 87 Bypass Route 90 Spacer Sheet Piece 92, 94 Drum Shaft 96 Support Frame 98 Bearing 100, 102 Gear 104 Coupling 106 Electric Motor 108 Controller 110 Thickness Sensor 112 112 Thickness Setting Device 113 Print quality setting device 114 Rotation angle sensor 116 Index arm 120 Type sensor 122 Type setting device

Claims (8)

[Claims] 1. An electrophotographic apparatus that transfers a toner image from a photosensitive medium onto an intermediate transfer member, and then transfers and fixes the toner image from the intermediate transfer member onto a recording medium, the moving speed of the intermediate transfer member. An electrophotographic apparatus is provided with a switching means for changing the number according to the type of the recording medium. 2. An electrophotographic apparatus for transferring a toner image from a photosensitive medium onto an intermediate transfer body, and then transferring and fixing the toner image from the intermediate transfer body onto a recording medium, the moving speed of the intermediate transfer body. An electrophotographic apparatus is provided with a switching means for changing the above according to the type and thickness of the recording medium. 3. The switching means includes an input means for inputting a type of the recording medium.
Or the electrophotographic apparatus of 2. 4. The input means is a material of the recording medium,
4. The electrophotographic apparatus according to claim 3, further comprising detection means for detecting a type based on a difference in configuration. 5. The input means is a material of the recording medium,
The electrophotographic apparatus according to claim 3, further comprising setting means for selecting a type based on a difference in configuration. 6. An electrophotographic mounting method comprising transferring a toner image on a photosensitive medium to an intermediate transfer member, and then transferring and fixing the toner image from the intermediate transfer member to a recording medium, wherein the intermediate transfer member is moved. An electrophotographic method, characterized in that the speed is changed according to the type of the recording medium. 7. An electrophotographic mounting method comprising transferring a toner image on a photosensitive medium to an intermediate transfer body, and then transferring and fixing the toner image from the intermediate transfer body onto a recording medium, wherein the intermediate transfer body is moved. An electrophotographic method, characterized in that the speed is changed according to the type and thickness of the recording medium. 8. The type of the recording medium is discriminated based on a difference in material and constitution of the recording medium.
The electrophotographic method according to claim 6 or 7.