Shadow comes both sides of the paper during printing

Dear
The thermal paper may old and expired this may test using a fresh paper, The thermal head of the printer may contaminated, clean with isopropyle alcohol,during power OFF. Also this may happen partial damage of thermal print head. It can solved on replacement of that.

Thanks.

Take the toner cartridge out of the printer. Shake it side to side. Reinstall it and print something.
See if that fixes the output.
Could also be the transfer roller.

I have had a similar problem since purchase 1 year ago. Mine has this issue on first 2-sided copy I print, problem is on the second side only. I disassembled the machine and could not discover the problem. However I did notice one paper transport roller (there are $) was askew. After reassembly all was well for about 40 copies then problem returned, I will remove that transport roller and retest machine

Had the same problem with LBP5000. Used the Cleaning Utility(Options/Cleaning) in the printer software, had to run it several times, the shadow did not go away the first time. Looks all right now.
Hope this helps.
Thor.

use plane paper of 60-80 gsm if your printed paper is offset/screen print it will repeat and shadow appears because of high temprature in fussing unit.

Your printer has a fail safe mechanism that pushs the paper that it's processing out to prevent any other jams during the printing process. Your rollers must have something jamming it's movement during printing. You will need to open the printer through the panels on the back, front, and side to ensure that you see the rollers and remove any paper or debrise blocking hitched on the rollers or in the printer. You may also want to ensure that the holders on the sides of the paper tray where the paper comes in are lined up correctly. Also, make sure not to pack the paper tray to capacity. Only use the tray half full.

The MP610 does support duplex printing.

Duplex Printing

The duplex printing function allows you to print data on both sides of a sheet of paper.
The procedure for performing duplex printing is as follows:
Performing automatic duplex printing
You can perform the duplex printing without having to turn over the paper.
1. Open the printer driver setup window, check the Duplex Printing check box, and confirm that Automatic is checked.

2. Select Normal-size Printing (or Fit-to-Page Printing, Scaled Printing or Page Layout Printing) from the Page Layout list.
3. When printing a document that has small margins, click Print Area Setup... and set the print area.
When you perform duplex printing, the print area of the document becomes slightly narrower than usual and the document may not fit on one page.

To print without reducing the page:
Select Use normal-size printing.
To reduce the page slightly during printing:
Select Use reduced printing.
4. Specify Staple Side.
The printer analyzes the Orientation and Page Layout settings, and automatically selects the best staple position. Check the Staple Side setting. If you want to change the setting, select another value from the list.
5. If necessary, click Specify Margin... and set the Margin width.
6. Click OK.
Duplex printing will be started.

Performing duplex printing manually
You can perform the duplex printing manually.
1. Check the Duplex Printing check box and uncheck the Automatic check box on the Page Setup tab.

2. Select Normal-size Printing (or Fit-to-Page Printing, Scaled Printing or Page Layout Printing) from the Page Layout list.
3. Specify Staple Side.
The printer analyzes the Orientation and Page Layout settings, and automatically selects the best staple position. Check the Staple Side setting. If you want to change the setting, select another value from the list.
4. If necessary, click Specify Margin... and set the Margin width.
5. Click OK.
If a media type other than Photo Paper Plus Double Sided is selected for Media Type on the Main tab:
When you execute print, the document will be printed on one side of a sheet of paper. When printing is complete, reload paper according to the displayed message and then click OK. The document will be printed on the opposite side.
If Photo Paper Plus Double Sided is selected for Media Type on the Main tab:
When you execute print, the document will be printed front and back alternately for one sheet at a time. Load the paper according to the displayed messages.
Note Duplex Printing is unavailable when:
- A media type other than Plain Paper, Photo Paper Plus Double Sided or Hagaki is selected from the Media Type list.
- Poster Printing is selected from the Page Layout list.
When Booklet Printing is selected from the Page Layout list, Duplex Printing and Staple Side appear grayed out and are unavailable.
After printing the front page, there is an ink drying wait time before starting to print the back page (Operation stops temporarily). Do not touch the paper during the time. You can change the Ink Drying Wait Time at Custom Settings on the Maintenance tab of the printer driver.
When you perform the automatic duplex printing for Hagaki, print an address first and then print your message.
Tip If you select Photo Paper Plus Double Sided for Media Type on the Main tab, the Duplex Printing check box on the Page Setup tab is not checked automatically. To perform duplex printing, check the Duplex Printing check box.
If the Media Type dialog box appears when performing borderless printing during duplex printing, select Plain Paper or Photo Paper Plus Double Sided.
When performing the automatic duplex printing, do not use any plain paper smaller than A5. Also, do not select any type of paper other than Plain Paper, Photo Paper Plus Double Sided or Hagaki at Media Type.
Photo Paper Plus Double Sided is highly recommended for printing photographs on both sides of a page.
If the back side of the paper becomes smudged during duplex printing, perform Bottom Plate Cleaning in the Maintenance tab.

One of 2 things, Replace the transfer cleaning blade. You may be able to clean it and get rid og the problem. The second thing to try is to replace the magenta drum, but thats less likely since you say it goes away in 3-4 pages.I suspect the transfer blade.

Heating unit (fuser) 's teflon roll is dirty causing ghosting. Either replace with new heating unit (it is on front top near paper output) or clean it.
It can be cleaned carefully with electonic cleaning spray (non grease) WITHOUT using any force (be patient) wiping with cloth and spraying again and again utill it is clean. Then spray silocone spray to cloth and wipe teflon with that.
Open unit: Remove mains and usb/network leads. Remove paper holder (printed papers) from top back. Under that you'll see small arrows on both sides. Push screwdriver to hole and release locks. After that you can raise dark lid from top. Under that on white lid there is 4 screws, open them. Open all back cover scews and take the cover out lifting from bottom edge. Open 1 screw from right cover (where network socket is. Lift white top cover a little bit and then you can open right side cover (from back to forward). Under cover there is flat cable coming from display unit. Open it and then you can remove top white lid. Push the rest of dark paper holder backwards (on top) and it opens and you'll see the power supply under that. When looking from back there is 1 screw at right holding black plastic roller plate. Open the screw and bend the plate to left (looking from back) Now you can see 50% of brown teflon roll that is around the heater lamp. Clean it with spray and cloth pushing CAREFULLY from bottom to top.
Do NOT push teflon horizontaly as there is nothing on back of teflon and it may broke. Underside there is a metal plate under teflon and you can use LITTLE force for wiping. You can rotate teflon pushing white gear at top (from top to bottom, it turns only this direction). When totally clean, wipe with cloth sprayed with silicone spray.
I do not know how long this helps (just did it by myself) but the printing result is perfect again with same color casettes than before.