WO2009124981A1

WO2009124981A1 - Method for adjusting the inking of charge patterns produced on a charge pattern carrier using toner in the developer station of an electrophotographic printing device

Info

Publication number: WO2009124981A1
Application number: PCT/EP2009/054258
Authority: WO
Inventors: Thomas Schwarz-Kock; Ralph Dorfner
Original assignee: OCé PRINTING SYSTEMS GMBH
Priority date: 2008-04-10
Filing date: 2009-04-08
Publication date: 2009-10-15
Also published as: DE102008018227B4; DE102008018227A1

Abstract

In order to control the supply of toner (TF) into the developer mixture stock for replacing the toner used during the inking of the charge patterns, the toner consumption (TVB) is determined according to the charge pattern to be inked, and a base adjustable variable (B_ST) is produced for the toner supply (TF) according to the determination of the toner consumption. The base adjustable variable (B_ST) is corrected according to a inking mark on the charge pattern carrier. For the fine correction of the inking of the charge patterns on the charge pattern carrier, the application tension (U_mv) on the inking roller is adjusted according to the inking mark.

Description

Method for adjusting the coloration of charge images formed on a charge image carrier with toner in the developer station of an electrophotographic printer

Electrographic printing or copying machines are known, see e.g. No. 6,246,856 B1. In such a printing or copying device, on a charge image carrier, e.g. a photoconductor belt, generated by a character generator charge images of the images to be printed. Subsequently, the charge image carrier is moved past developer stations, one per color. These transport toner to the charge image carrier. According to the charge images on the charge image carrier, the toner transfers to the charge image carrier and colors it. In the next step, the toner images are transferred to a substrate and fixed on it. The exact sequence of the printing process can be found in US Pat. No. 6,246,856 B1, the content of which is hereby included in the disclosure.

For developing the charge images, a developer station may be used, e.g. is constructed according to US 7,340,202 B2. From a developer mix store

The toner and carrier take out a inking developer ^mixture in which the toner is triboelectrically charged. Adjacent to the inking roller, there is provided a developer roller or applicator roller which takes in toner from the inking roller due to an electric field existing between the developer roller and the inking roller and transports it to the charge image carrier. There Toner walks into a ^¬ nem developer gap for coloring the charge images on the charge image carrier. The on the developer roller after development remaining toner is then abge cleans ^¬ by a cleaning roller of the developer roller. In developing the charge images on the charge image carrier of the state of the developer mixture plays a big role ^¬ SSE, since the printing process is thereby enced significantly affected. Therefore, the developer mix has to be kept in its optimal working environment. During the printing process, toner is taken from the developer mixture for developing or coloring the charge images on the charge image carrier in accordance with the print images to be printed. The amount of toner discharged from the developer mixture is replaced with new toner from a toner container. The toner is applied by treatment in the developer mixture electrical charges; the toner is activated triboelectrically. This activation is a prerequisite for the subsequent coloring of the latent charge images (development of the print image). The quality of the activation of the toner and the degree of wear of the developer mixture is significantly affected by the mixing concentrator ^¬ trationsverteilung of toner and carrier in Entwicklerge-. The developer mix should therefore be kept in its optimum working range, above all by regulating the toner concentration.

From US 5,581,335 and US 2006/0269303 it is known to determine the toner concentration by means of a sensor-based measurement of a toner mark on the printing material and to regulate this as a function of the measurement result. Since the sensor ^¬ based measurement is influenced by other variables, such as the electrical charging and aging of Entwicklerge- premix, it is known to replace this provision with a pixel-based control as a function of the pressure to be generated image.

A further control of the toner concentration can be taken from US 5,386,276. For this purpose, a inking mark is applied to the charge ^¬ image carrier, wherein the To ^¬ nermenge or thickness of the toner carpet by a sensor is measured and the To ^¬ nerkonzentration is set in the developer mixture as a function of the measured signal.

The problem to be solved by the invention is to provide a method with which the developer mixture can be kept in an optimal working range.

This problem is solved according to the features of claim 1.

The invention thus resides in a new networked control which combines the toner concentration control with the inking control.

The base load of the toner discharge and thereby the toner ^¬ consumption by the inking of the charge image on the charge image carrier can be detected with the aid of the current print image utilization and the toner production in the developer mix in the developer station according controlled by one of them dependent basic control value ^¬ the. The print image utilization can be detected on the basis of the pixels of the charge image and thus of the print image, which are controlled by the character generator. It is weighted with an-average by ^¬ toner consumption per pixel and according to the currently set Einfärbestufe.

This base load is corrected to maintain an optimum Ar ^¬ beitsbereich of the developer mixture, on the basis of the request voltage on the inking roller. For each one-time level of the charge images, a setpoint voltage or a permitted voltage range can be specified. Depending on the application voltage actually set, the toner delivery and thus the toner concentration in the developer mixture will be adjusted if the measurement of the inking mark has shown that the toner quantity on the inking mark deviates from the nominal value. Finally, a fine correction takes place in that the application voltage is set on the developer roller after measurement and as a function of the inking mark.

The coloring of the charge images is thus regulated in three layers:

- the current print image usage determines the base ^¬ manipulated variable, so the toner production in the Entwicklerge ^¬ mixed; the base manipulated variable is corrected as a function of the inking mark on the charge image carrier;

- For fine adjustment (fine correction) of the coloring, the application voltage of the inking roller is regulated as a function of the inking mark on the charge image carrier.

The invention has the particular advantage that the toner concentration in the developer station is controlled by the toner promotion in the developer station, a process that is relatively slow, but a rapid adjustment of the toner application to the charge images by means of the inking mark by changing the application ^¬ voltage the inking roller takes place.

Further developments of the invention will become apparent from the dependent claims.

The setting of the base control variable can be controlled by pixels (pixel = picture element). For this purpose, the number of pixels to be generated per charge image (print image) is counted and calculated from the count and the toner consumption per pixel ^¬ the toner consumption for the development of charge images to print images as a base control value. The toner consumption per pixel can be weighted by the set ink level, as this also has an influence on the toner consumption. In order to adapt the base manipulated variable even more precisely to the toner consumption, a correction factor can be formed with the aid of the application voltage on the inking roller and the measurement of a staining mark applied to the charge image carrier. The correction factor can be formed from the ratio of the amount of toner per inking mark to the application voltage in the production of the inking mark; This ratio is compared with a predetermined setpoint value and, if deviated, the toner delivery into the developer supply is corrected. The setpoint can be formed depending on the inking level.

Finally, a fine correction of the inking of the charge image by controlling the application voltage on the inking roller in dependence of the coloring of the Einfärbe ^¬ mark can be made on the charge image carrier. As a result, the toner supply to the charge image carrier can be changed quickly.

Compliance with the optimum operating range for the Ent ^¬ wicklergemisch done so on the one hand by evaluating the current toner discharge (control by pixel count) and on the other by a system based on the results of inking controlling. Dye control and toner concentration control are linked with it. The sensor-based measurement of the toner concentration in the developer mixture is thus superfluous. However, it could be used to check the plausibility of the regulatory processes.

Maintaining the optimum working range of the developer mixture according to this method has a number of advantages: a toner concentration sensor is superfluous; - there is an automatic compensation of Prozessto ^¬ leranzen; - Mixture damaging operating conditions (over / undertone) are detected and avoided;

it achieves a constant amount of toner discharge and thus less developer mix damage.

With reference to embodiments, which are illustrated in the figures, the invention will be further explained.

1 shows a known developer mixing station with representation of the flow of the developer mixture mixture. Fig. 2 is a schematic representation of the method for maintaining the working range of the developer mixture.

1 shows a developer station ES in principle according to US Pat. No. 7,340,202 B2, US Pat. No. 7,340,202 B2 is hereby included in the disclosure. From a developer station ES, a inking roller 1, a developer roller 2 and a cleaning roller 3 are illustrated to explain the invention. The remaining components of a developer station

ES, such as Toner reservoirs, developer mix bottoms or dredgers are known and may be used e.g. US 7,340,202 B2 are taken. A developer mixture GE of toner and magnetic carrier is taken from the developer mixture sump of the inking roller 1, at the

Passing transported ^¬ advantage developer roller 2, for example a jump roller, wherein the toner to the developer roller 2 passes. The remainder of the developer mixture GE may be passed between the developer roller 2 and the cleaning roller 3 in a known manner in order to assist the cleaning of a residual toner remaining after the development of charge images on the charge image carrier (not shown in FIG. 1) on the cleaning roller 3.

This course of the developer mixture GE is supported by elekt ^¬ P generic potentials, which are shown in FIG. 1. At the inking roller 1 is a potential Pl, at the developer mixing roller 2 a potential P2 and at the cleaning roller 3, a potential P3. Under the pre-reduction ^¬ that the toner is negatively charged, the potential Pl is more negative than the potential P2. The potential P3 at the cleaning roller 3 is more positive than potential P2 at the developing roller 2 to assist the transfer of the negatively charged toner to the cleaning roller 3.

The proper development of charge images with toner to print images requires that the developer mixture is always kept in the optimum working range, so that the charge images can be printed according to e.g. The coloring level set by the operator can be optimally colored. This object is achieved according to the invention according to the method shown in principle in Fig. 2. In Fig. 2, the interaction of three control operations has been combined, which build on each other and interlock: a) the toner promotion in the developer supply of the developer station ES is controlled pixel, so that is the

Basic offer of the amount of toner at the developer's store; is generated to a base control variable; b) the toner supply is corrected in dependence on a Einfärbe ^¬ mark on the charge image carrier; c) Finally, there is still a fine correction of the toner output by adjusting the application voltage to the inking roller. 1

a) Pixel-controlled toner delivery (TF (pix)) into the developer supply of the developer station ES

By a pixel-controlled toner delivery (TF (pix)), the amount of toner that is consumed by the development of Ladungsbil ^¬ to the printed image, as the base load of To ^¬ nerförderung TF nachgefördert in the developer station ES. If the consumption increases or decreases accordingly more or less toner per time in the developer mixture nachgefördert. This is shown in FIG. 2 as a basic offer "toner quantity". 2, the relationship between the pixel counter, which counts the number of pixels per print image, and toner delivery TF is shown in FIG. 2. The pixel counter is the control input and the toner delivery TF is the manipulated variable 2. Line Z2 plots the toner consumption TVB per pixel (TVB (pix)) over the time t in the upper region Z2.1 and the toner delivery TF per pixel (TF (pix)) in the lower region Z2.2 per pixel, for example, depending on the set Einfärbestufe, then the toner promotion TF and vice ^¬ versa increases accordingly. When the toner consumption TVB per pixel is known, from the count of the pixel counter, the basic control ^¬ size B_ST for the toner promotion TF rat in the Entwicklervor- be calculated.

b) Correction of Toner Carrying TF according to a)

From the lines Zl and line Z3, which surround the line Z2, it can in principle be deduced how a correction K_TM of the basic offer G_TM of toner quantity takes place. This is the

Toner quantity TM _{opc determined} for the set _{Einfärbestufe} ei ^¬ ne _{inking mark} on the charge _{image carrier} . The ^¬ se may differ from the set amount of toner, which is designated in line Zl as desired. The resulting "delta" between the setpoint and the measured value is used to correct the base control variable B_ST. For this purpose, a ratio V _{1 of} the toner quantity TM _opc to the application _voltage U _MV of the inking _roller 1 is formed. Depending on the selected coloring, there is a set value SV ₁ to be determined beforehand. If the ratio V ₁ at time i does not coincide with the setpoint value S_V, a correction of the toner delivery TF is made. This means that the toner delivery TF, which until now has only controlled the basic supply G_TM via the quantity of pixels, now experiences an adjustment to below or above. This can either be an adjustment due to other losses, eg caused by dusting, or due to changed mixture properties. Stems associated with a change in toner concentration.

In Fig. 2 there is shown how (shown in the diagram Dl) on the measured amount of toner TMQ _PCΛ line 1, and the dependence of the amount of toner TMQ _PC by the application voltage U _MV correction quantity dTF (Vi) to the basic service, the Ba ^¬ sisstellgröße B_ST , is produced.

Diagram D1 shows for V ₁ = TM (U _1nV ) the setpoint to be _controlled . Since the amount of toner TM _opc is present as a measured value, the application _voltage U _{mv is} known, it can be determined on the basis of the Dia ^¬ gram Dl, whether the toner delivery TF, so the base control variable B_ST should be corrected. Depending on this, a correction value of the toner delivery dTF (V ₁ ) (positive or negative) is added to or subtracted from TF (pix). The diagram D 1 can be implemented in the printer control by software.

c) Fine correction

Here, the toner output to the charge image carrier for coloring the charge images is influenced. Due to the toner quantity measurement TM _opc (line 1) via the inking mark, the toner application on the developer roller 2 and thus the toner supply to the charge image carrier is changed. This ge ^¬ schieht by adjusting the application voltage U _mv at the inlet coloring roller 1 (line Z4). This makes it possible to react quickly to amendments ^¬ stakes in Einfärbevermögen. From Fig. 2 it follows that the deviation of TM _0Pc from the target value is determined as dTM _opc and from the diagram D2 the change ^¬ tion of the application voltage dU _mv for the inking roller 1 is determined, which is used for fine correction.

In the diagram, the dependence of D2 dTM of dU _mv is Darge ^¬ represents. If the measured value TM _opc from the setpoint dTM _opc from ^¬ deviates, D2 can be seen that the application voltage U _mv of the inking roller 1 in order to change dU _mv, so that the To- nerangebot be achieved at the charge image carrier for the desired inking of the charge image can. The graph D2 can also be realized by software in the Dru ^¬ sugar control.

LIST OF REFERENCE NUMBERS

ES developer mix station

P electrical potential

E electric field GE developer mix

G_TM Basic supply of toner

K_TM Toner amount correction

F_TA Fine adjustment of toner output

TM amount of toner OPC charge image carrier

TVB toner consumption

TF Toner Cartridge

U _mv electrical voltage at the inking roller

D Diagram Z line

1 inking roller

2 developer roller

3 cleaning roller

Claims

claims

1. A method for adjusting the coloration of charge images formed on a charge image carrier with toner in the developer blending station of an electrophotographic printing device in which a developer mixture of toner and carrier is removed from a mixture supply and egg ^¬ ner developer mixing roller is fed through which the coloring of the charge images , a) in which (for controlling the toner promotion TF) in the developer mixture stock for replacement of the power consumed by the Einfär ^¬ bung of the charge image toner,

- the toner consumption (TVB) is determined in dependence of the charge images reproduced einzufär- thereof and depen ^¬ gig a base manipulated variable (B_ST) for the toner conveying ^¬ tion (TF) is generated,

- the base manipulated variable (B_ST) is corrected in depen ^¬ dependence of an inking on the charge image carrier, b) in which the fine correction of the coloring of the image charge ^¬ on the charge image carrier, a toner application clamping ^¬ voltage (U _mv) on the inking roller (1) in Dependence of the inking mark is set.

2. The method of claim 1, wherein the adjustment of the base manipulated variable (B_ST) is pixel-controlled.

3. The method of claim 2, wherein the number of pixels per charge image is counted and from the count result and the toner consumption (TVB) per pixel, the base control variable (B_ST) is determined.

4. The method according to claim 2 or 3, where toner consumption (TVB) per pixel is weighted by the set ink level.

5. Method according to one of the preceding claims, in which a correction factor (K_ST) is formed from the ratio (v) toner quantity (TM _opc ) per _{inking mark} to the application _voltage (U _mv ) at the _{inking roller} (1) in order to correct the base control variable (B_ST), this ratio is compared with egg ^¬ nem predetermined desired value and at the base devia- manipulated variable deviation (B_ST) for toner development (TF) is corrected.

6. The method of claim 5, wherein the setpoint is formed depending on the Einfärbestufe.

7. The method according to any one of the preceding claims, wherein the fine correction of the coloration by controlling the application voltage (U _mv ) of the inking roller (1) in dependence on the coloring of the inking mark on the charge ^¬ image carrier takes place.