EP0858619A1

EP0858619A1 - Toner feed means for a developer station of a printer or a photocopier

Info

Publication number: EP0858619A1
Application number: EP96920718A
Authority: EP
Inventors: Reinhold Schmidl; Christian Heil
Original assignee: Oce Printing Systems GmbH and Co KG
Current assignee: Canon Production Printing Germany GmbH and Co KG
Priority date: 1995-10-31
Filing date: 1996-06-27
Publication date: 1998-08-19
Anticipated expiration: 2016-06-27
Also published as: US6021294A; EP0858619B1; WO1997016769A1; DE59601629D1

Abstract

The invention relates to pneumatic toner feed means for a developer station of a printer or a copier. The said means contains toner storage containers (A, B) each allocated to the developer chambers of the developer station and acting as intermediate storage units which are linked to the developer chambers of the developer station by supply ducts (ZK). The toner is supplied from bottle-shaped transport containers (TA, TB) by a vacuum transport means to the toner storage containers (A, B) which have controllable solenoid valves (VA, VB). The toner level is detected by way of control means (C) with associated capacitive sensors (15/1, 15/2), and when it exceeds a predetermined level the valves are opened; there is therefore automatic toner refill. The control means (C) may contain a priority control system (PS) which preferably refills toner of the main printing colour.

Description

description

Toner supply device for a developer station of a printing or copying machine

Such a toner supply device is known in principle from EP-Bl 0 332 669. It is a device for the pneumatic filling of toner from a bottle-shaped transport container into a toner storage container, in which toner is completely sucked out of the transport container with the help of negative pressure and thus transported into the toner storage container. The toner reservoir is connected to a developer station with only a single developer chamber. It contains a mixing device made of a wire bracket and a foam metering roller arranged in the connection area to the developer station, via which toner is metered into the developer station in printing mode, depending on its fill level. The toner reservoir itself is subdivided into a suction space and a settling space by means of a filter, the settling space being connected to the toner bottle via a hose and the suction space being coupled to a vacuum blower.

Furthermore, from WO 94/27193 an electrographic printing device is known with which it is possible to print multicolor on a tape-shaped recording medium in simplex and duplex mode. For this purpose, the printing device contains a plurality of separate developer stations arranged one behind the other or next to one another, which separately color developer areas assigned to the developer stations on an electro-graphic intermediate carrier (photoconductor).

In multi-color simplex operation, the so-called spot color operation, a printed image with a first color is first printed onto the recording medium, then the printed image is fixed and then the recording medium is returned to the printing station and a printed image with a second one Color printed and then fixed in a second pass through the fuser. The transfer printing station is thus run through with a single recording medium in two recording medium webs arranged next to one another in parallel. Corresponding developer areas on the photoconductor are assigned to the recording medium webs. Since photoconductors, be they tapes or drums, cannot be of any width, it is necessary to arrange the developer areas next to one another on the photoconductor without a substantial distance. The associated developer stations must therefore also be arranged close to each other. For this purpose, it has already been proposed to use a single developer station with several separate developer chambers, in each of which differently colored toners, e.g. B. red toner and black toner is included.

If toner is supplied to the developer chambers from a conventional toner storage container with a predetermined capacity, large-volume containers are necessary to maintain printing operations. These take up a lot of space and therefore cannot be used in connection with a developer station with several developer chambers. If smaller containers are used, this shortens the printing operation.

It has been found that with multi-color printing with

High-speed printers of the type mentioned are predominantly only printed in a single color, for example black. Individual areas of the printed image are only occasionally highlighted by a different color or multi-colored graphics or images are inserted. This results in a different level of consumption of the different types of toners. The printing time is thus limited by the capacity of the container with the most used toner. If, on the other hand, if the containers are of different sizes according to the statistical consumption, there is a risk that the sudden change in multicolor operation will cause the differently colored toner components to be used at an early stage. need and therefore the printing operation must be interrupted.

The object of the invention is therefore to design a toner supply device of the type mentioned at the outset in such a way that continuous printing operation is ensured.

This object is achieved in accordance with the features of the first patent claim.

Advantageous embodiments are characterized in the subclaims.

In the case of the invention, the toner storage containers are designed as real intermediate stores, to which toner is supplied more or less continuously from storage bottles (transport containers) depending on their fill level. A peumatic conveyor with negative pressure is used. If the level falls below at the same time in the case of a plurality of toner supply containers, a priority circuit ensures that the toner component which is most used during printing is first conveyed out of the corresponding transport container and the printing operation can thus be continued.

The toner is conveyed from the toner bottles (transport container) into the toner boxes (toner storage container) by means of vacuum using the suction principle. In order to ensure sufficient suction power at low negative pressure, suction is alternately only extracted from one bottle when there is permanent negative pressure on the suction channel. For this purpose, the suction channel with suction cycle valves is designed so that a multi-way valve is created. It is thus possible to control the filling of the toner boxes solely by selectively operating the valves. The toner box is primarily filled with the main printing ink via the priority circuit. Embodiments of the invention are shown in the drawings and are described in more detail below with reference to the drawings. Show it

FIG. 1 shows a schematic sectional illustration of a developer station with toner storage containers arranged thereon,

FIG. 2 shows a schematic illustration of a toner box with two toner storage containers A and B,

FIG. 3 shows a schematic representation of the supply of toner to the toner supply container A,

FIG. 4 shows a schematic illustration of the toner supply to the toner supply container B,

FIG. 5 shows a schematic representation to explain the position of the representations used,

FIG. 6 shows a schematic illustration of view W of FIG. 5,

FIG. 7 shows a schematic illustration of view Y of FIG. 5,

FIG. 8 shows a schematic illustration of view X of FIG. 5,

FIG. 9 shows a schematic illustration of view Z of FIG. 5,

Figures 10 and 11 is a schematic diagram illustrating the function of the closures and

FIG. 12 shows a schematic illustration of the sealed bearings in the area of the partition between adjacent transport containers. An electrophotographic printing device for multi-color printing of tape-shaped recording media in simplex and duplex operation, as is known from WO 94/27193, contains a developer station with an associated toner box as a toner buffer, which is described in more detail below with reference to the figures. In principle, the developer station consists of two developer stations arranged in a single housing, separated by a thin partition and coupled to one another via the partition, each of which in principle has a functional structure known from WO 94/03842. The function of the rollers involved in the development process and their technical designation is described in WO 94/03842. In this respect, this document is part of the present disclosure.

The developer station shown in FIG. 1 with the associated toner box contains a housing G which can be pulled out via rails in the device and has two developer chambers E which are separated by an intermediate wall ZW. Arranged in each of the developer chambers E are two developer rollers WI and W2 made of a rotatable hollow roller with a magnetic stator arranged therein, and a metering roller DW made of plexiglass with an exposure device arranged therein. A transport roller TW stored in the developer sump below the developer rollers transports the developer mixture to the developer rollers WI and W2. Arranged outside the developer chambers E in the outlet region of the developer station is a single carrier-catching roller TFW spanning the developer chambers E, which is constructed analogously to the developer rollers. All of the rollers except the transport roller are grouped around a photoconductor drum FT in accordance with the course of the developer gap. They rotate in the direction of the arrows shown. They are driven together via a gear arranged laterally on the housing G of the developer station. Arranged above the developer chambers E is a toner box TBO, shown in FIGS. 1 and 2, with the toner reservoirs A and B respectively assigned to the developer chambers E, which are coupled to the developer chambers E via feed channels ZK. Each toner reservoir A and B is about one

Filter F is divided into a settling room AR and a suction room SR.

The settling chamber AR contains a mixing device M in the form of a wire bracket 11 mounted on a mixer shaft 10 and a conveyor device FE transporting toner to the developer chambers E in the form of a metering roller 12 made of foam. Mixer shaft 10 with wire bracket 11 mounted thereon and metering roller 12 are driven via a gear with chain drive 13 and electric motors 14 (FIGS. 6 and 7) arranged laterally on toner storage containers A and B. Each toner reservoir A and B has a separate drive.

In each settling area AR of each toner storage container A and B there is a capacitive sensor 15/1, 15/2 as a fill level sensor for detecting the fill level of the toner.

The toner storage container A receiving a first toner of a first color and the second toner of a second

Color-absorbing toner storage containers B are constructed in mirror image, together they form the TBO toner box. In the region of their side walls 16, the toner storage containers A, B are connected to one another in a form-fitting manner by means of screws. The drives 13, 14 for the mixing device M and the conveying device FE are located in the area of their other side walls 17. Mixing device M and the conveying device FE are each mounted in the side walls 16, 17.

The separating wall from the side walls 16 arranged in the border area between adjacent toner supply containers A, B contains the roller bearings 18 shown in FIG Mixing device M and the conveying device FE, the roller bearings 18 being sealed off from the settling spaces AR of the toner storage containers A, B by seals 19 (Simmerrings). Toner storage container TB and developer station E are connected to one another in an electrically conductive manner, but are insulated from the housing of the receiving device, since during printing operation the toner storage container TBO and developer station E are connected to a bias voltage with respect to the photoconductor drum FT. All electrical and mechanical components of the TBO toner box with connection to the device must therefore be constructed in an electrically insulated manner.

As can be seen in particular from FIG. 2 in connection with the principle representations of FIGS. 10 and 11, each settling area AR of the toner storage containers A and B is via a supply line 20/1 and 20/2 with a toner transport container TA, TB in the form of a Toner bottle connected. The toner container TA contains toner of a first color, e.g. black, the toner container TB, toner of a second color, e.g. red. Each suction chamber SR of the toner reservoir A or B can in turn be coupled to a suction channel 21 via a closure in the form of a suction cycle valve VA, VB, to which a vacuum-generating device in the form of a blower is flanged. The valves VA and VB are designed as solenoid valves with a valve piston 22, which in the energized state

Inlet opening 23 to suction channel 21 opens and, when deenergized, closes inlet opening 23 via a spring element. This ensures that all inlet openings 23 are closed in the event of a power failure. The valves VA and VB are assigned to the respective toner storage containers A and B. During the printing operation, negative pressure is constantly applied to the suction channel 21. The associated valve VA or VB is opened so that the corresponding toner from the toner bottles TA or TB can now be supplied to the corresponding settling spaces AR of the toner storage containers A or B. The other valve VB, VA remains closed. The toner from the storage bottles TA, TB thus arrives with the help of the negative pressure applied into the sedimentation areas AR and is intercepted there by filter F. This filter F prevents the toner from passing into the suction spaces SR. The alternative switching of the valves VA and VB is necessary so that there is always sufficient negative pressure available to transport the toner. It is thus possible to ensure that the toner is transported safely from the toner supply bottles TA, TB to the settling areas AR of the toner supply containers A and B even at a low negative pressure. In the actual printing operation, both valves VA and VB can be closed so that the negative pressure has no negative influence on the transport of toner to the developer chambers of the developer station.

To supply, for example, black toner from the transport container TA into the toner storage container A of the toner box TBO, the valve VA is energized in accordance with the illustration in FIG. 3, and the inlet opening 23 is thus opened. The valve VB is deenergized and thus the associated inlet opening 23 is closed. The toner air mixture thus arrives from the toner transport container TA via the feed line 20/1 into the settling chamber AR of the toner storage container A. The toner settles in the settling chamber AR and the transport air passes through an inlet channel 24 arranged in the side walls 16 and 17 through the inlet opening 23 on the valve VA in the suction channel 21 to the vacuum blower. For transporting, for example, red toner from the toner transport container TB into the toner supply container B, the valve VA is closed in accordance with the illustration in FIG. 4 and the valve VB is opened by energization. Thus, via the feed channel 20/2, a mixture of toner and air passes from the toner transport container TB through a through-channel 25 of the toner supply container A into the settling area AR of the toner supply container B. The red toner settles there in the settling area AR. The suction air passes through an opening 26 of the side wall 17 of the toner reservoir B into a channel 27 to the valve VB with its inlet opening 23 and from there via the through the toner reservoir A and B led central suction duct 21 to the blower of the vacuum generating device.

The supply of the toner from the toner flanges TA and TB into the corresponding toner storage containers A and B is controlled via a microprocessor-controlled control device C (FIG. 2), which is coupled on the one hand to the capacitive sensors 15/1 and 15/2 of the toner storage containers A and B and others ¬ side with valves VA and VB. The control C detects the fill level of the toner in the settling spaces AR of the toner supply containers A and B via the capacitive sensors 15/1 and 15/2. If the toner supply drops below an inputable level, the control C opens the corresponding valves VA or VB Toner storage container A or B, with which toner automatically reaches the associated settling areas AR. In order to ensure that if the toner levels in the two toner reservoirs A and B fall below simultaneously, the main printing ink, for example black, of the currently running printing operation is refilled as a matter of priority. For this purpose, the control device C is coupled to a priority control GS. This priority control is connected or is part of the device control, not shown here. It records the current operating state of the printing device, ie the print with the current main color, for example black, for example by recording and evaluating the data stream of the characters to be printed in the image memory. It transmits this operating state in the form of a signal to the control unit C, which then gives priority to the filling of the toner storage container A (black toner color) or the filling of the toner storage container B (red toner color) in the usual electronic manner by doing so depending on the priority associated valve VA or VB opens. The priority can also be entered in advance if, for example, black printing is to be ensured. The toner supply device according to the invention for a two-color developer station of a printing or copying machine has been described above with reference to a toner box TBO, which consists of two mirror-image arranged toner supply containers A and B, which are assigned to the developer station according to the developer chambers. If, for example, a full-color operation is to be supplied to a developer station which contains, for example, three or four developer chambers with differently colored toner components, a corresponding number of toner supply containers can be arranged in an analogous manner, which are controlled by corresponding valves. This means that each printing color can be used as the main color, meaning that full color printing is possible with all colors. The toner supply quantity is only determined by the size of the external toner supply bottles.

The described split toner box of FIG. 2 can also be easily mounted on the developer station E. For this purpose, as shown in FIGS. 1 and 9, the entire toner box is placed on the developer station and is mechanically centered by means of centering elements. The electrical components of the TBO toner box are automatically connected in the area of a plug connector 28 to a mating connector 28/1 of the developer station. A circumferential seal 29 seals the attachment area or the feed channels ZK to the developer station. In order to be able to clean or replace the filter F in the suction space SR, the toner supply containers A or B are releasably covered with a cover 30 fastened by screws.

Claims

claims

1. Toner supply device for a developer station of a printing or copying machine, which has several developer chambers (E) for separately coloring several developer areas arranged on an electrographic intermediate carrier (FT) with toner

- The toner chambers (A, B) assigned to the developer chambers (E) as intermediate storage, which are coupled to the developer chambers via feed channels (ZK);

- A vacuum transport device which sucks off toner from various types of toners and stores (AR) the toner supply containers (A, B) and supplies separate vacuum transport devices; - Controllable closures (VA, VB) and

- A control device (C), which is coupled to the closures (VA, VB) and to a sensor device (15/1, 15/2) which detects the toner fill level in the respective toner storage containers (A, B) a toner supply container (A, B) opens the associated closure (VA, VB) so that toner is transported from the transport container (TA, TB) into the toner supply container (A, B) via the vacuum transport device.

2. Toner supply device according to claim 1, wherein the vacuum transport device is constantly activated at least during the printing operation, and the supply of the different types of toners takes place solely by selectively opening the closures (VA, VB).

3. Toner supply device according to one of claims 1 or 2, wherein the control device (C) has a priority control (PS) which causes that when falling below a Toner¬ fill level in several toner storage containers (A, B) first in the toner storage container (A) with assigned highest Priority toner is refilled from a transport container (TA).

4. Toner supply device according to one of claims 1 to 3, wherein the toner storage container (A, B) each via a filter (F) in a via a supply line (20/1, 20/2) coupled to a toner transport container (A, B) (AR) and a suction space (SR) are subdivided, and the suction space (SR) can be connected via a closure (VA, VB) to a suction channel (21) which is coupled to a device generating a vacuum.

5. Toner supply device according to one of claims 1 to 4, with a designed as a solenoid valve controllable closure (VA, VB) which is open in the energized state and closed in the de-energized state.

6. Toner supply device according to one of claims 1 to 5, wherein the toner storage container (A, B) each contain at least one mixing device (M) and a toner to the developer chambers (E) transporting conveying device (FE).

7. Toner supply device according to claim 6, with at least one partition (16) arranged in the border area between adjacent toner supply containers (A, B) with bearings (18) for the mixing device (M) and the conveying device (FE), whereby Bearings (18) are sealed off from the toner supply containers (A, B) by seals (19).

8. Toner supply device according to one of claims 6 or 7, having a toner reservoir (A) receiving a first toner of a first color and a toner reservoir (B) receiving a second toner of a second color, which are constructed in mirror image, the toner reservoir (A , B) are positively and releasably connected to one another in the region of their one side wall (16), and in the region of their other side wall (17) each have drives (14) for the mixing device and the conveying device.

9. Toner supply device according to one of claims 1 to 8, wherein the toner storage container (A, B) and developer station (E) are electrically conductively connected to one another, but are insulated from the receiving device and are present at least during a printing operation against a bias voltage.

10. Toner supply device according to one of claims 1 to 9, with a capacitive sensor (15/1, 15/2) as Füllstandεεensor.