DE3907875C2 - - Google Patents

Description

The invention relates to an electrophotographic printer with an upper and a lower housing part, the upper part of the housing hinged to the lower part of the housing is brought.

DE 36 24 060 A1 is already an electrophotograph shear printer known, the housing of two housing halves exists, with the upper half of the housing hinged on the un teren half of the housing is attached. In addition, in the a support frame pivotally attached to the lower half of the housing, in which a development unit with an interchangeable Toner cartridge and a cleaning unit each as separate interchangeable process units are arranged. With this be known construction are however no guidance present that could take effect if the upper casing half is moved towards the lower half of the housing.

JP 62-2 60 166 is an electrophotographic printer known, which also has two housing sections, the  unfolded are attached to each other. At the top A process unit is used in the housing section a photoconductive drum, a developing device and comprises a cleaning device. In the upper case section is for the inclusion of the process unit le diglich provided a guide device. When closing operation of the upper housing section towards the lower housing section there is no actual Management of the process unit, but only the last one Section of the closing movement becomes the process unit in moved a target position.

A similar construction is from JP 61-2 79 870 knows. In this known construction, too Process unit in a housing section of an upper Ge part of the house pushed in firmly. The closing movement of the upper housing section towards the lower Ge however, the section of the house remains with this known one Construction for guiding an inserted process unit unused.

Furthermore, DE 38 07 430 A1 and DE 38 06 946 A1 Described imaging devices that a second lige housing, wherein an upper housing portion is hinged to a lower housing section in such a way that the two housing sections are unfolded can. A process unit with a development device device and a cleaning device can be used for this provided recess in the upper housing section be set. In the construction according to DE 38 07 430 A1 is also a control device for controlling the opening and closing movement of the upper housing section with respect to the lower housing section hen.

The object underlying the invention is an electrophotographic printer mentioned above to create the kind in which to exchange one Parts or assemblies subject to wear Printer only opened the two housing parts the parts or assemblies to be replaced can then be immediately removed or replaced that can and an exact positioning of all individual parts of the printer purely by closing the two housings parts is realized again.

This object is achieved by the in the patent pronounced 1 solved characteristics.

By the construction according to the present invention the particular advantage is achieved that the support frame over a much longer distance towards one exact positioning can be moved and therefore when Unfolding the housing parts in a relatively far from be ner target position remote position easily can be moved in a direct, special the relevant units can be easily exchanged is.

Particularly advantageous refinements and developments the invention emerge from the subclaims 2 to 4th

In the following, the invention will be described with reference to embodiments play explained with reference to the drawing. It shows:  

Fig. 1 is a sectional view of an older construction of an image recorder, which is performed, for example, as a laser printer;

Fig. 2 is a sectional view taken along line II-II in Fig. 1;

Fig. 3 is a perspective view of an optical writing unit in the laser printer of Fig. 1;

Fig. 4 to 7 different views, based on which the Be the operation of the laser printer shown in Figure 1 is explained.

Figure 8 is a sectional side view of an embodiment form of a printer with features according to the invention.

Fig. 9 to 10 show a perspective view and a Be tenansicht a construction of a special mechanism for a to a position in the printer of Figure 8 is provided guide part of replaceable unit in an openable housing part.

Fig. 11 is an illustration on the basis of which the way of working of the printer shown in Fig. 8 is explained;

Figures 12 and 13 in section side views of each ver different embodiments with features according to the invention. and

Fig. 14 is a sectional side view of another type of printer.

For a better understanding of the invention, a conventional image recorder shown in FIGS . 1 to 3 will be briefly described. In Figs. 1 to 3 of the image recorder is carried out at example as a laser printer. As Darge provides, the laser printer 10 has a photoconductive drum 12 which is rotatable in a direction indicated by an arrow. A main loader 14 , a development unit 16 , a transfer loader 18 and a cleaning unit 20 are successively arranged around the drum 12 in the rotational direction of the drum 12 . A toner cartridge 16 a, from which toner is supplied to the development unit 16 , is held interchangeably on the printer 10 . The cleaning unit 20 has a cleaning part 20 in the form of a cutting edge and a cartridge 20 b for toner 20 b removed from the drum 12 during cleaning for accommodating toner particles collected during cleaning. The cleaning unit 20 is also held interchangeably on the printer 10 .

An optical writing unit 22 is set so that a writing position 24 on the drum 12 is imagewise exposed by it, which is fixed between the main charger 14 and the development unit 16 . The main loader 14 is arranged under the drum 12 , while the writing unit 22 is arranged under the drum 12 , the developing unit 16 and the cleaning unit 20 . The transfer loader 18 is arranged above the drum 12 . A paper cassette 26 is arranged below the writing unit 22, from the paper cassette 26 is fed from station an image transfer a sheet of paper disposed between the transfer charger 18 and the drum is set 12th In particular, sheets of paper are fed individually from the paper cassette 26 on a predetermined transport path through a feed roller 28 and a friction part, which rests with pressure on the feed roller 28 . A sheet of paper is passed along the Ent coil unit 12, a registration roller pair to reach 32, which is disposed above the developing unit 16 and by an upper roller 32 and a roller 32 formed a lower b. The alignment roller pair 32 controls the sheet of paper towards the image transfer station so that the sheet of paper and an image on the drum 12 match each other. The fixing unit 34 is arranged in the transport port after the image transfer station. Furthermore, a shelf 26 is provided near the fixing unit 34 .

In the writing unit 22 , a light beam which has been controlled or modulated by an image data signal and which is emitted by a laser unit 38 is reflected by a first mirror 40 so that it hits a deflecting mirror 44 which is attached to the output shaft of a scanner motor 42 . As a result, the light beam repeatedly scans a predetermined angular range. The deflected light beam is corrected by an fR lens arrangement 46 so that the light beam is focused on a line in the writing position 24 of the drum 12 and the correction point is shifted at a constant speed. The light beam which emerges from the fR lens arrangement 46 is guided via a second mirror 48 and a cylindrical lens 50 so that it reaches the drum 12 . A main scan is performed by deflecting the light incident on the drum 12 , while a sub-scan is performed by rotating the drum 12 .

As a result, an image is written in connection with the image data signal on the drum 12 , whereby an electrostatic, latent image is generated.

The various elements of the writing unit 22 are attached directly to a bottom cover 52 which forms a part of the housing of the printer 10 . A synchronization sensor 54 is also provided.

The latent image on the drum 12 is developed into a toner image by the developing unit 16 and then transferred to the sheet of paper by the transfer loader 18 , which is fed from the alignment roller pair 32 . The sheet of paper carrying the toner image is then separated from the drum 12 , conveyed to the fixing unit 34 for fixing the toner image, and then discharged into the tray 36. Toner particles remaining on the drum 12 after the image transfer are made removed by means of the cleaning unit 20 , whereby the drum is then prepared for a further image generation cycle.

As stated above, the writing unit 22 is fixed under the drum 12 and the developing unit 16 , and the paper cassette 26 is arranged under the writing unit 22 . The transfer loader 18 and the alignment roller pair 32 are fixed over the drum 12 . Such an arrangement is advantageous because the space in which the above-mentioned units are to be accommodated, and therefore the overall size of the laser printer 10 is reduced.

A cover 56 which can be opened forms an upper housing part of the printer 10 and, as shown in FIG. 1, can be pivoted about a shaft 58 between a closed and an open position. The Transferla the 18 and the two rollers 32 a and 32 b of the alignment roller pair 32 are movable or pivotable together with the cover 56 . The drum 12 is held so that it remains in the housing of the printer 10 or is lifted together with the cover 56 when the cover 56 is opened.

Now a sheet of paper is said to have jammed ver in the transport path near the transfer loader 18 or the alignment roller pair 32 . As shown in Fig. 4, the Ab can then cover 56 which len the transfer charger 18 and the two Rol 32 a and 32 b of the regist rollers 32 carries, to be opened, is set completely free so that the transport path. Now the jammed sheet can be easily removed. If necessary, the cover 56 can also be constantly tensioned in the direction of the open position by a spring and is then usually held in the closed position by a hook part.

As shown in Fig. 5, only the upper roller be attached to the cover 56. 18 together with the Transferla 32 a of the regist rollers 32. This arrangement is just as effective in removing a jammed sheet as the arrangement previously described. If, as shown in FIGS. 6 and 7, an arrangement is selected in which the drum 12 and the two rollers 32 a and 32 b or only the upper roller 32 a of the alignment roller pair 32 with the cover 56 can be lifted up, the When a change is due, drum 12 can be easily removed from the remaining parts.

Of the various units or parts of the laser printer 10 , the toner cartridge 16 and the cleaning unit 20 have to be exchanged most frequently, because the toner cartridge 16 a accommodates fresh toner, which is consecutively consumed by the development unit, and because the cleaning unit 20 consists of the cartridge 20 b for unused toner for collecting excess toner and the cleaning part 20 a, which wears out as a result of repeated cleaning operations. The cartridge 20 b for unused toner is accommodated in the cleaning unit 20 , depending on the type of device, or is provided independently of the cleaning unit 20 .

As shown in Fig. 6, the toner cartridge 16 a and the cleaning unit 20 can be replaced by opening the cover 56 , to which the register roller pair 32 and the drum 12 are attached. However, since these parts are provided separately from each other, they must be replaced individually, and the new parts must then be attached again at the predetermined locations. In particular, if the toner cartridge 20 b is provided independently of the cleaning unit 20 , its replacement is extremely time-consuming and tedious compared to another cartridge.

Preferred embodiments with features according to the invention are described below. In these embodiments, the same or similar parts as those of the printer 10 shown in Figs. 1 to 7 are designated by the same reference numerals.

In Fig. 8, a printer with features according to the invention is Darge, which is also designed as a laser printer. The laser printer 60 has a cartridge 20 b for unused toner, which is arranged separately from the cleaning unit 20 and is exchangeably held on the housing of the printer 60 . A toner cartridge 16 a and the cleaning unit 20 , which has only one cleaning blade 20 a, are executed in a single exchange unit, which are held by a support frame 64 in a predetermined position relationship. With this configuration, the toner cartridge 16 a, the cleaning unit 20 and the cartridge 20 b for unused toner can be opened simply by opening the upper housing part of the printer 60 , ie a cover 56 , which is to be opened together with the register roller pair 32 and the drum 12 . to be replaced and then the exchange unit 62 can be pulled out in a direction indicated by an arrow 66 . As shown in Fig. 8, a guide plate 68 is provided, through which a position is determined in which the exchange unit 62 should be held. The guide plate 68 can be designed such that it can be moved automatically from a setting position, for example, into the position shown in FIG. 8 when the upper housing part in the form of the cover 56 is opened; this then makes the exchange of the exchange unit 62 even easier.

In FIGS. 9 to 11, a special construction is one Me mechanism shown to the guide plate 68 to move in a ver unlocked relation with the cover 56. As shown, the guide plate 68 is rotatably supported on a bolt 72 which protrudes from a frame 70 of the laser printer 60 . A stop member 74 is fixed to the guide plate 68 and has an arcuate slot 74 a. A bolt 76 protrudes from the frame 70 and is received in the slot 74 a of the stop member 74 , whereby a pivoting range of the guide plate 68 is defined within a certain angular section. A torsion spring 80 is wound around a bolt 78 which projects from the frame 70 . The spring 80 biases the guide plate 68 clockwise, as can be seen from the figures. Whether an external force that wants to push the guide plate 68 down is missing, the guide plate 68 is held in the position shown in FIG. 9, in which the lower end of the slot 74 a of the stop part bears against the bolt 76 .

As shown in FIG. 10, a protrusion in the form of a boss 82 projects downward on each of the opposite sides of the lower surface of the cover 56 . When the cover 56 is pivoted in the direction of its closed position around the shaft 58 , the lower ends of the extension parts 82 press protruding parts 68 a, which are provided on opposite sides of the guide plate 68 , downward against the force of the torsion spring 80 . As a result, the toner cartridge 16 a and the cleaning unit 20 of the exchange unit 62 , which is held on the guide plate 68 , brought into their predetermined setting position in the Druckerge housing. A hook part 84 is held on the end of the cover 56 which is distant from the shaft 58 and is hooked to a locking pin 86 , which protrudes from the printer housing.

In order to replace the exchange unit 62 , the hook part 84 on the cover 56 is released from the locking pin 86 , as shown in FIG. 11. If the locking pin 86 released cover 56 is raised around the shaft 58 as a fulcrum, the lower ends of the sets 82 are moved away from the guide plate 68 , with the result that the guide plate 68 is turned clockwise by the torsion spring 80 the shaft 72 is pivoted. This pivoting movement of the guide plate 68 is ended when the lower end of the slot 78 a of the stop member 74 abuts the bolt 76 . In this position, as shown in Fig. 11, the exchange unit 62 , which has been retained by the guide plate 68 , substantially takes an intermediate position between the opposite ends of an opening which is defined between the cover 56 and the printer housing; in this position, the exchange unit 62 can be conveniently inserted or removed.

FIG. 12 shows a further embodiment with features according to the invention, in which the cleaning unit 20 has a cartridge 20 b for unused toner. In this case, the cleaning unit 20 having the toner cartridge 16a and the cartridge 20b for unused toner gen only peo in a replaceable replacement unit 62 A available. In this embodiment, a guide plate 68 A for positioning the replacement unit 62 A can also be designed so that it can be pivoted into a locked position with respect to the cover 56 , so as to facilitate replacement.

FIG. 13 shows yet another embodiment with features according to the invention, in which the main loader 14 is likewise contained in an exchangeable exchange unit 62 B. The main charger 14 is a solid state discharge device having an electrode provided on the surface of a thin dielectric plate. In contrast to a conventional discharge device of the so-called hairline type, in which only one corona wire can be replaced, this type of discharge device is replaced as a whole. Therefore, in this embodiment, the accommodation of the main charger 14 in the exchange unit 62 B, as shown in Fig. 13, is desirable and advantageous.

In the illustrated embodiments, the writing unit 22 is arranged under the drum 12 , while the trans ferlader 18 is fixed over the drum 12 . However, the inven tion is similarly applicable to any other embodiment of an image recorder, such as in a laser printer 60 C, as shown in Fig. 14. The laser printer 60 C of FIG. 14 has an upper housing part 90 , in which the writing unit 22 is provided, and a lower housing part 92 , in which the drum 12 is provided. Although image data is optically written on the drum 12 from above, a toner image is transferred to a sheet of paper by the transfer charger 18 disposed under the drum 12 .

The photoconductive element can of course also be designed as a band instead of a drum. These parts of the laser printer, which can easily be contaminated, and for example are arranged close to the cleaning unit 20 , can preferably be accommodated in the exchangeable exchange unit 62 . Usually, the like parts are a dust glass 94 , which is assigned to the writing unit 22 , and a cylindrical lens 50 A, which also serves as a dust glass, as shown in FIGS . 8 and 12.

The invention thus creates a printer in which the interchangeability of different interchangeable ones Parts is relieved. Also with this printer the running costs are reduced as a photoconductive element and a development unit, which are expensive, not in a replaceable exchange unit are accommodated.

Claims (4)

1. Electrophotographic printer with

• an upper and a lower housing part, the upper housing part being hingedly attached to the lower housing part,
• a supporting frame pivotably attached to the lower housing part, which is moved into an elevated position when the upper housing part is opened and to which an exchange unit consisting of a toner cartridge and a cleaning unit is detachably fastened,
• - The support frame in its pivoting movement relative to the lower housing part leading and positioning guide devices and with
• - On the upper housing part protrusions through which the support frame with the exchange unit is pressed when closing the upper housing part in its target position in the lower housing part, wherein it is positio ned by the guide devices in its correct position in the lower housing part.

2. Printer according to claim 1, characterized in that a photoconductive recording element ( 12 ) on the upper housing is removably supported. 3. Printer according to claim 1 or 2, characterized in that the cleaning unit ( 20 ) of the exchange unit ( 62; 62 A, 62 B) has a cartridge ( 20 b) held on the support frame and removed from the photoconductive recording element ( 12 ) Takes up toner. 4. Printer according to claim 1 or 3, characterized in that a charging device ( 14 ) as a whole is removably mounted on the support frame ( 62 B).