DE20320437U1 - Device for fastening a character generator with the aid of adjustment devices - Google Patents

Abstract

Device for fastening a character generator (10) in a printer or copier,
in which a character generator (10) is arranged at a distance from the surface of a photoconductor (12),
wherein the character generator (10) is held by at least one adjusting device (26, 28) which has a first section (38), a second section (40) and an intermediate connecting section (42),
wherein the first section (38) is fixed with respect to the surface of the photoconductor (12), the second section (40) is fixed to the character generator (10) and is movable relative to the first section (38), and the connecting section (42 ) elastically connects the first section (38) and the second section (40),
and in which an adjustment means (30) is provided which shifts the second section (40) relative to the first section (38) and thereby moves the longitudinal axis (18) of the character generator within a plane (16) perpendicular to the surface of the photoconductor (12) .
whereby means for remote control of the ...

Description

The The invention relates to a device for fastening a character generator in a printer or copier. Such a character generator generates by illuminating a photoconductor surface there is a latent one Charge image, colored with toner particles, transferred to a recording medium and is fixed on it. Typically the photoconductor is on a drum or a band. At the featured The device is the character generator at a distance from the surface of the device Arranged photoconductor.

On such a character generator typically has an elongated one carrier with a surface facing the photoconductor on which a large number of light-emitting elements are arranged in a row. each These light-emitting elements are produced when the photoconductor is illuminated a pixel of a line of the charge image. This is done by light emitted to each light emitting element an optical device focused at a point on the photoconductor surface. The sharpness this figure essentially determines the sharpness of the Print image.

The optical device is often by a So-called Selfoc bar is formed, in which gradient fibers embedded in plastic map the emission surfaces of the light-emitting elements onto the photoconductor surface. In order to obtain a picture that is as sharp as possible, character generators have been proposed in which the Selfoc bar can be adjusted relative to the line of light-emitting elements. Despite such an adjustment possibility within the character generator, a sharp image can only be obtained on the photoconductor surface if the light-emitting elements are at the correct distance from it, ie the character generator as a whole is fixed at the correct distance from the photoconductor surface.

by virtue of the relatively shallow depth of field Selfoc bar must be the Character generator and the photoconductor in conventional devices with great accuracy be built in to get a sharp image, which is high cost caused.

It also occurs with commercially available Selfoc strips always the problem that due to manufacturing defects individual light-emitting elements with a shallower depth of field are imaged than the rest, so that even if the manufacturer specifies Tolerance range for the installation results in a blurred printed image in places. Such Selfocs must be discarded will and lead currently too high disposal costs.

Out DE-A-197 18 435 a character generator is known in which not only the distance of the optical device to the line of light emitting Elements can be set, but the optical device additionally around a parallel to the line of light-emitting elements Axis is pivotable. By swiveling the optical device the angle is changed with which the light rays enter or leave it. By the change the entry and Beam angles of the light beams can compensate for aberrations by the optimal installation position of the character generator different installation position are caused. However, this can Only a small error in the installation position can be corrected. Moreover the adjustment is relatively difficult to carry out.

The The invention has for its object a device for fastening of a character generator in a printer or copier, at which even with a low tolerance of the optics to the installation position of the character generator a sharp print image can be achieved with simple means.

This Task becomes in a device of the type mentioned solved, that the character generator by at least one adjustment device which is held a first section, a second section and has an intermediate connecting portion, the first section is stationary with respect to the surface of the photoconductor is fixed, the second section is attached to the character generator is and is movable relative to the first section and the connecting section connects the first and the second section elastically, and in the an adjustment means is provided which the second section opposite the first section moves and thereby the longitudinal axis of the character generator moved within a plane perpendicular to the surface of the photoconductor, means for remote control of the adjusting means are provided.

With With the help of the adjustment device, the distance of the light-emitting Elements for the photoconductor surface can be adjusted even after installing the character generator, so that such great precision is not required for the installation itself. The Means for remote control of the adjustment means facilitate the adjustment the adjustment device, since this is often not easily accessible. In particular, the adjustment device can be adjusted by suitable means for remote control during a trial run of the printer or copier can be set, wobewi the effects of the setting are checked directly on test prints can.

In an advantageous embodiment, the adjusting means is formed by a bolt element, which has a first and a second threaded section, the pitch of which are different. In this case, a first internal thread is preferably provided in the first section, in which the first threaded section is accommodated, and a second internal thread is provided in the second section in which the second threaded section is accommodated. With one revolution of the bolt element, the second section is thus displaced relative to the first by a distance which corresponds to the difference in the pitch of the two threads. A fine and uniform adjustability is achieved. Furthermore, such an adjustment means is self-locking, ie no additional device is required by which the bolt element would have to be fixed in its set position.

In An advantageous development is that of the bolt element created connection of the first and second section a spring loaded. This creates a game of the bolt element prevents in the internal threads and the self-locking of the bolt element elevated.

In The connecting section is a particularly advantageous embodiment formed by a leaf spring element. A leaf spring is suitable due to their high torsional stiffness, the second section when adjusted compared to the first section in to lead a level. As detailed below explains this property becomes leadership the longitudinal axis of the character generator within a plane perpendicular to the surface of the Exploited photoconductor. Preferably the first section is the second section and the connecting section as a one-piece profile part educated. Such a profile part can be done by milling or Extrusion inexpensively produce.

In a preferred embodiment the character generator by two of the adjustment devices described held at a distance from each other along the longitudinal axis of the character generator are arranged. This allows both the distance as well as the angle of the character generator to the surface of the Photoconductor can be adjusted.

In a particularly advantageous development of the device according to the invention is for remote control of the adjustment device in the work area of the printer or copier an actuator provided that is coupled to the adjusting means such that an actuation of the actuator an adjustment of the adjusting means causes. The workspace poses represents the area for the operator when operating the printer or copier is achievable. In this development, the operator can use the adjusting means thus adjust in operation, i.e. he can the mounting position of the Adjust the character generator during operation. Thus, it can have the effect of Adjustment to the print image immediately using a test print or a trial copy and in this way quickly and easily find the optimal setting.

The actuator is preferably formed by a handle that with the adjusting means is mechanically coupled by a flexible shaft. A flexible one Shaft has the advantage that it can easily be moved from the adjusting device into one for the Operator easily accessible Area led can be. The handle is preferably operated by a rotary knob formed in the area of the rest Controls of the device Outside arranged on the device housing is. On the housing there is preferably a scale on which the position of the rotary knob is readable. about the scale is a certain setting reproducible.

In An advantageous development is with the shaft or the bolt element a stop element is connected in a rotationally fixed manner and a shaft stop is provided, on which the stop element when leaving a shaft angle range is stopped. The stop element and shaft stop allow the Shaft can only be rotated in a certain angular range. In order to it can be ensured that the adjustment means are not caused by excessive turning overwhelmed the wave become.

In an advantageous development are between stop element and Shaft stop drive plates, which are on both sides of the disk surface protruding driver elements, freely rotatable on the Shaft or the bolt element arranged that by relative rotation of two Adjacent drive disks face each other Driver elements come into play that stop the element Rotation of the shaft opposite the first driver plate with its driver element facing it comes into play and that a driver element of the last driver disk by turning opposite the shaft stop comes into contact with this. By using such driving plates, as explained in more detail below, the angular range in to which the shaft can be adjusted, in particular an angular range that is more than 360 °.

Preferably, the driver disks have a recess for receiving the shaft, and the driver elements are formed by a shoulder which has the shape of a ring segment with an inner and outer radius in the plan and which is arranged concentrically with the recess, and is on one side in each case Driving disc formed a shoulder with an annular floor plan, which is arranged concentrically with the recess and the outer radius is at most as large like the inner radius of the driver element paragraph. The annular shoulder forms a contact surface for an adjacent drive plate, the driver element of which is guided along the outside of the annular shoulder.

Further Advantages and features of the solution according to the invention result from the following Description which in conjunction with the accompanying drawings the invention using an exemplary embodiment explained. In it show:

1 : a view of the photoconductor and the character generator, looking at its longitudinal axis from the front,

2 a section through the elements of the device according to the invention in a plane perpendicular to the surface of the photoconductor,

3 : a rear view of the front adjustment device,

4 : a section along the line A – A of 3 .

5 : a rear view of the rear adjustment device,

6 : a section along the line B – B of 5 .

7 : an exploded view of the shaft, stop element, bolt element, drive plates and shaft stop,

8th : the elements of 7 in composite form, and

9 : a perspective view of the bottom and top of the drive plates.

In 1 is a character generator 10 shown at a distance from the surface of a photoconductor 12 is arranged. The photoconductor layer 12 is on a rotating drum 14 arranged. With reference number 16 is to the surface of the photoconductor 12 vertical plane referred to in the longitudinal axis 18 of the character generator 10 lies. The character generator 10 has a variety of LEDs 20 that are in a row along the longitudinal axis 18 are arranged. That from the LEDs 20 light emitted is by means of a Selfoc bar 22 on the surface of the photoconductor 12 focused. In 1 are exemplary light rays with 24 designated. The character generator 10 is by a front adjustment 26 and a rear adjuster 28 held. About the adjustment devices 26 and 28 becomes the character generator on the case 36 attached to the device (see 2 ).

To get a sharp print image, it has to be from each of the LEDs 20 emitted light on the surface of the photoconductor 12 to be focused on one point. For this it is necessary that the LEDs 20 and the photoconductor 12 are at the correct distance from each other. The adjustment devices 26 and 28 allow you to set this distance.

In 2 are the essential elements of a device according to the invention for fastening the character generator 10 in a printer or copier in a cut along the plane 16 (see. 1 ) shown: the front adjustment device 26 , the rear adjuster 28 , each with an adjusting device 30 , and flexible waves 32 through which the adjusting means 30 with knobs 34 are connected, which are outside the device housing 36 are located.

As in 2 you can see the adjustment devices 26 and 28 a first section each 38 on the device housing 36 is attached, a second section 40 who is at the sign generator 10 is attached, and a connecting portion 42 that the first and second section 38 . 40 elastically connects. Because the axis of the photoconductor drum, not shown 14 also with the housing 36 is rigidly connected, is the first section 38 in relation to the surface of the photoconductor 12 fixed. With the help of the adjusting device 30 can the second section 40 compared to the first section 38 in the drawing plane of 2 , ie in the surface of the photoconductor 12 vertical plane 16 be adjusted. Through independent adjustment on the adjustment devices 26 and 28 can thus the longitudinal axis 18 of the character generator in the plane 16 be adjusted.

The following is the structure and function of the adjustment devices 26 and 28 with reference to the 3 to 6 explained.

The adjusters 26 and 28 are constructed according to the same principle and only differ somewhat in their shape, which in the exemplary embodiment shown is adapted to the corresponding space in the device. Similar parts in both adjustment devices 26 . 28 are identified by the same reference number.

3 and 5 show a rear view of the adjustment devices 26 respectively. 28 , ie in 2 viewed from the right. 4 and 6 show the adjustment devices in the same section as in 2 , only enlarged. As in 4 and 6 To recognize, the adjustment devices are designed as a profile part, with a first section 38 , a second section 40 and a third section 42 , The third section 42 has the function of a leaf spring over which the first section 38 and the second section 40 elastic ver are bound.

A bolt element is used as an adjusting means 30 provided a first threaded section 44 and a second threaded section 46 has different pitches. The second thread section 46 is in a matching internal thread 48 screwed that in the second section 40 is trained. The first thread section 44 is in a mother 50 with suitable internal thread 54 housed, which with clamping screws 52 on the first section 38 is rotatably attached. In the exemplary embodiment shown, the first threaded section has 44 a pitch of 0.8 mm per revolution and the second thread section 46 a pitch of 0.5 mm per revolution. Will the bolt element 30 rotated 360 °, the second section moves depending on the direction of rotation 40 by the pitch difference of 0.3 mm on the first section 38 to or away from him. The adjustment with the pitch difference enables a very fine adjustment.

The connecting section 42 is aligned horizontally in the force-free state. By turning the bolt element 30 it becomes S-shaped upwards (as in 4 shown) or down (as in 6 shown) bent. As in 3 and 5 the adjustment devices can be seen 26 and 28 relatively wide, whereby the leaf spring-like connecting section 42 receives high torsional rigidity. On the other hand, the leaf spring-like connecting portion exercises 42 a low restoring torque compared to a pivoting of the second section within the plane 16 out. This means that the leaf spring-like connecting section 42 when adjusting the adjustment devices 26 and 28 no significant bending stress on the character generator 12 exercises, which could change its appearance.

Between the second section 40 and the mother 50 is a coil spring 56 clamped so that over the bolt element 30 a play-free connection of the first and second sections 38 . 40 is formed. The feather 56 is in the middle section in the 4 and 6 cut away to look at the bolt element 30 release. To guarantee freedom from play, the spring must 56 be so stiff that the restoring force of the leaf spring 42 in its downward deflected position (see 6 ) exceeds.

The bolt elements 30 of the adjustment devices 26 and 28 are about flexible waves 32 with knobs 34 that are outside the case 36 are connected in a rotationally fixed manner. The knobs 34 are located in the working area of the device, ie in the area in which the controls to be used when operating the device are located and which is accessible to the operator during operation. Thus, the adjustment devices 26 . 28 via the knobs 34 be adjusted during operation, and the effect of the adjustment can be assessed directly on the print image of test prints or copies. This is an adjustment of the character generator 10 Can be carried out quickly and easily in the printer or copier. There is a scale on the outside of the housing 56 attached to the setting of the knobs 34 can be read. This makes settings easily reproducible.

The flexible waves 32 and the pressure hull 34 represent a special means for remote control of the bolt elements. However, it is expressly pointed out that the invention is not limited to this special means for remote control. Within the scope of the invention, the means for remote control can generally be formed by an actuating element which is coupled to the adjusting means of the adjusting device (for example mechanically and / or electromagnetically) in such a way that actuation of the actuating element causes an adjustment of the adjusting means.

In the exemplary embodiment shown, the adjustment range of the second section is 40 compared to the first section 38 limited by the fact that the two sections touch each other (as in 4 shown) or that the head 58 the bolt element 30 on the mother 50 strikes (as in 6 shown). If used carelessly, however, the bolt element could become loose 30 in these two extreme positions bite what the thread 44 . 46 . 48 . 54 permanently overused. In an improved embodiment is therefore one of the shaft 32 accessible angular range restricted by other means that in 7 in exploded view and in 8th are shown in composite form.

In 7 is a section of the flexible shaft 32 shown with a bolt element 30 ' is rotatably connected. The bolt element 30 ' is constructed similarly to the bolt element described above 30 , and similar sections are in the bolt element 30 ' with the same reference numerals as for the bolt element 30 but with a dash.

The bolt element 30 ' has next to the threaded sections 44 ' and 46 ' , which also have different pitch heights, a thread-free section 60 on which a stop element 62 is rotatably attached. There are also corrugated washers 64 and drive plates 66 provided, the function of which is explained below. On the mother 50 ' is a wave stop 67 educated. In composite form, which in 8th is shown are the corrugated washers 64 and the drive plates 66 freely rotatable on the thread-free section 60 arranged and is the first threaded portion 44 ' into the mother 50 ' screwed.

In 9 is a perspective view of the bottom (left) and top (right) of a drive plate 66 shown. The drive plate 66 has a circular recess 72 to accommodate the thread-free section 60 the bolt element 30 ' , There is a driver element on each of their top and bottom sides 68 arranged in the form of a paragraph with a floor plan in the form of a segment of a circle. At the top of the drive plate 66 is also a ring-shaped heel 70 trained, which has the same height as the driver elements 68 , The driver elements 68 and the annular heel 70 are concentric with the recess 73 arranged. The outer radius of the annular shoulder 70 is slightly smaller than the inner radius of the driver element 68 , The drive plates 66 are so on the unthreaded section 60 arranged that an upper and a lower side of two adjacent panes are facing each other. The ring-shaped heel offers 70 a support surface for the underside of the adjacent drive plate. Two adjacent drive plates can be rotated against each other until their mutually facing drive elements 68 come to a stop.

Will the wave 32 towards the mother 50 ' twisted, the stop element comes 62 with the driver element 68 at the top of the drive plate closest to it. Will the wave 32 rotated further, the following drive plates are gradually taken along until the last drive plate with the drive element on its underside with the shaft stop 67 comes into play. This is the wave 32 accessible range of rotation angle set. By the number of drive plates 66 and the shape of the driver elements 68 the size of the angular range can be specified. In the exemplary embodiment shown, it is slightly less than three revolutions of the shaft 32 ,

When the shaft is twisted 32 changes due to the stroke of the thread 44 ' the distance between the stop element 62 and mother 50 ' , So that the driver elements 68 do not jump over each other when there is an increased distance between the driver elements 66 Well slices 64 arranged for a uniform distance between the drive plates 66 to care.

In the bolt element shown 30 ' have the threaded sections 44 ' and 46 ' a different diameter. This has manufacturing advantages, since both threads can be cut one after the other from the same side, the bolt with the thread-free section 60 is clamped.

10

character generator

12

photoconductor

14

Photoconductor drum

16

level perpendicular to the surface of the photoconductor

18

longitudinal axis of the character generator

20

light elements

22

Selfoc bar

24

light rays

26

front adjusting

28

rear adjusting

30 30 '

bolt element

32

flexible wave

34

handle

36

casing

38

first section

40

second section

42

connecting portion

44 44 '

first threaded portion

46 46 '

second threaded portion

48

second inner thread

50, 50 '

mother

52

clamping screw

54

first inner thread

56

coil spring

58

head the bolt element

60

threadless section

62

stop element

64

wave washer

66

driver disc

67

shaft stop

68

dogging

70

annular heel

72

recess

Claims (14)

Device for fastening a character generator ( 10 ) in a printer or copier where a character generator ( 10 ) at a distance from the surface of a photoconductor ( 12 ) is arranged, in which the character generator ( 10 ) by at least one adjustment device ( 26 . 28 ) which has a first section ( 38 ), a second section ( 40 ) and an intermediate connecting section ( 42 ), the first section ( 38 ) in relation to the surface of the photoconductor ( 12 ) is fixed, the second section ( 40 ) on the character generator ( 10 ) is fixed and relative to the first section ( 38 ) is movable, and the connecting section ( 42 ) the first section ( 38 ) and the second section ( 40 ) connects elastically, and in which an adjusting means ( 30 ) is provided that the second section ( 40 ) compared to the first section ( 38 ) moves and thereby the longitudinal axis ( 18 ) of the character generator within one level ( 16 ) perpendicular to the surface of the photoconductor ( 12 ) moved, means for remote control of the adjusting means ( 30 ) are provided. Device according to claim 1, characterized in that the adjusting means ( 30 ) is formed by a bolt element which has a first threaded section ( 44 . 44 ' ) and a second threaded section ( 46 . 46 ' ), the pitch of which is different. Device according to claim 2, characterized in that in the first section ( 38 ) a first internal thread ( 54 ) is provided in which the first threaded section ( 44 . 44 ' ) and in the second section ( 40 ) a second internal thread ( 48 ) is provided in which the second threaded section ( 46 . 46 ' ) is housed. Apparatus according to claim 3, characterized in that the by the bolt element ( 30 . 30 ' ) created connection of the first ( 38 ) and second section ( 40 ) by a spring ( 56 ) is loaded. Device according to one of the preceding claims, characterized in that the connecting section ( 42 ) is formed by a leaf spring element. Device according to one of the preceding claims, characterized in that the first section ( 38 ), the second section ( 40 ) and the connecting section ( 42 ) are designed as a one-piece profile part. Device according to one of the preceding claims, characterized in that the character generator ( 10 ) by two essentially identical adjustment devices ( 26 . 28 ) is held at a distance from one another along the longitudinal axis ( 18 ) of the character generator ( 10 ) are arranged. Device according to one of the preceding claims, characterized in that on the operating side of the printer or copier an actuating element ( 34 ) is provided, which with the adjusting means ( 30 . 30 ' ) is coupled such that an actuation of the actuating element ( 34 ) an adjustment of the adjustment means ( 30 . 30 ' ) causes. Apparatus according to claim 8, characterized in that the actuating element by a handle ( 34 ) is formed, which with the adjusting means ( 30 . 30 ' ) through a flexible shaft ( 32 ) is mechanically coupled. Apparatus according to claim 9, characterized in that the handle by a rotary knob ( 34 ) is formed in the area of the other controls of the device on the outside of the device housing ( 36 ) arranged Apparatus according to claim 10, characterized in that the housing ( 36 ) a scale ( 56 ) at which the position of the rotary knob ( 34 ) can be read. Device according to one of claims 9 to 11, characterized in that with the shaft ( 32 ) a stop element ( 62 ) is non-rotatably connected and that a shaft stop ( 67 ) is provided on which the stop element ( 62 ) is stopped when leaving a wave angle range. Device according to claim 12, characterized in that between the stop element ( 62 ) and shaft stop ( 67 ) Driving disks, the driving elements protruding from the disk surface on both sides ( 68 ), freely rotatable on the shaft ( 32 ) or the bolt element ( 30 . 30 ' ) are arranged in such a way that their respective mutually facing driver elements come into abutment due to the relative rotation of two adjacent driver disks, that the stop element ( 62 ) by rotating the shaft ( 32 ) against the first driving plate with its driving element facing it and that a driving element of the last driving plate rotates with respect to the shaft stop ( 67 ) comes into play with this. Device according to claim 13, characterized in that the driving disks ( 66 ) a recess ( 72 ) for receiving the shaft ( 32 ) or the bolt element ( 30 . 30 ' ) have that the driver elements ( 68 ) are formed by a shoulder, which has the shape of a ring segment with an inner and outer radius and which is concentric with the recess ( 72 ) and that on each side of each drive plate ( 66 ) a paragraph ( 70 ) is designed with an annular plan that is concentric with the recess ( 72 ) is arranged and whose outer radius is at most as large as the inner radius of the driver element shoulder.